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Android 7.0, (N) Definición de compatibilidad

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Tabla de contenido

1. Introducción

Este documento enumera los requisitos que se deben cumplir para que los dispositivos sean compatibles con Android 7.1.

El uso de "DEBE", "NO DEBE", "REQUERIDO", "DEBE", "NO DEBE", "DEBE", "NO DEBE", "RECOMENDADO", "PUEDE" y "OPCIONAL" es según el IETF. estándar definido en RFC2119 .

Tal como se usa en este documento, un "implementador de dispositivos" o "implementador" es una persona u organización que desarrolla una solución de hardware/software que ejecuta Android 7.1. Una “implementación de dispositivo” o “implementación” es la solución de hardware/software así desarrollada.

Para ser consideradas compatibles con Android 7.1, las implementaciones de dispositivos DEBEN cumplir con los requisitos presentados en esta Definición de compatibilidad, incluidos los documentos incorporados a través de referencia.

Cuando esta definición o las pruebas de software descritas en la sección 10 sean silenciosas, ambiguas o incompletas, es responsabilidad del implementador del dispositivo garantizar la compatibilidad con las implementaciones existentes.

Por esta razón, el Proyecto de código abierto de Android es tanto la referencia como la implementación preferida de Android. Se RECOMIENDA ENCARECIDAMENTE a los implementadores de dispositivos que basen sus implementaciones en la mayor medida posible en el código fuente "upstream" disponible en el Proyecto de código abierto de Android. Si bien, hipotéticamente, algunos componentes pueden reemplazarse con implementaciones alternativas, se RECOMIENDA ENCARECIDAMENTE no seguir esta práctica, ya que pasar las pruebas de software será sustancialmente más difícil. Es responsabilidad del implementador garantizar la total compatibilidad de comportamiento con la implementación estándar de Android, incluida y más allá del conjunto de pruebas de compatibilidad. Finalmente, tenga en cuenta que ciertas sustituciones y modificaciones de componentes están explícitamente prohibidas por este documento.

Muchos de los recursos vinculados en este documento se derivan directa o indirectamente del SDK de Android y serán funcionalmente idénticos a la información en la documentación de ese SDK. En los casos en que esta Definición de compatibilidad o el Conjunto de pruebas de compatibilidad no estén de acuerdo con la documentación del SDK, la documentación del SDK se considera autorizada. Todos los detalles técnicos proporcionados en los recursos vinculados a lo largo de este documento se consideran por inclusión como parte de esta Definición de compatibilidad.

2. Tipos de dispositivos

Si bien el Proyecto de código abierto de Android se ha utilizado en la implementación de una variedad de tipos de dispositivos y factores de forma, muchos aspectos de la arquitectura y los requisitos de compatibilidad se optimizaron para dispositivos portátiles. A partir de Android 5.0, el Proyecto de código abierto de Android tiene como objetivo abarcar una variedad más amplia de tipos de dispositivos, como se describe en esta sección.

Dispositivo portátil Android se refiere a una implementación de dispositivo Android que normalmente se usa sosteniéndolo en la mano, como reproductores de mp3, teléfonos y tabletas. Implementaciones de dispositivos portátiles Android:

  • DEBE tener una pantalla táctil integrada en el dispositivo.
  • DEBE tener una fuente de energía que proporcione movilidad, como una batería.

Dispositivo de televisión Android se refiere a una implementación de dispositivo Android que es una interfaz de entretenimiento para consumir medios digitales, películas, juegos, aplicaciones y/o TV en vivo para usuarios sentados a unos diez pies de distancia (una "interfaz de usuario de 10 pies" o "reclinada"). ”). Dispositivos de televisión Android:

  • DEBE tener una pantalla integrada O incluir un puerto de salida de video, como VGA, HDMI o un puerto inalámbrico para visualización.
  • DEBE declarar las funciones android.software.leanback y android.hardware.type.television.

El dispositivo Android Watch se refiere a una implementación de dispositivo Android diseñada para usarse en el cuerpo, quizás en la muñeca, y:

  • DEBE tener una pantalla con una longitud diagonal física en el rango de 1,1 a 2,5 pulgadas.
  • DEBE declarar la característica android.hardware.type.watch.
  • DEBE admitir uiMode = UI_MODE_TYPE_WATCH .

La implementación de Android Automotive se refiere a una unidad principal del vehículo que ejecuta Android como sistema operativo para una parte o la totalidad del sistema y/o la funcionalidad de infoentretenimiento. Implementaciones de Android Automotive:

  • DEBE tener una pantalla con una longitud diagonal física igual o superior a 6 pulgadas.
  • DEBE declarar la característica android.hardware.type.automotive.
  • DEBE admitir uiMode = UI_MODE_TYPE_CAR .
  • Las implementaciones de Android Automotive DEBEN admitir todas las API públicas en el espacio de nombres android.car.* .

Todas las implementaciones de dispositivos Android que no encajan en ninguno de los tipos de dispositivos anteriores DEBEN cumplir con todos los requisitos de este documento para ser compatibles con Android 7.1, a menos que el requisito se describa explícitamente como aplicable solo a un tipo de dispositivo Android específico de arriba.

2.1 Configuraciones de dispositivos

Este es un resumen de las principales diferencias en la configuración del hardware por tipo de dispositivo. (Las celdas vacías indican "MAY"). No todas las configuraciones están cubiertas en esta tabla; consulte las secciones de hardware relevantes para obtener más detalles.

Categoría Rasgo Sección Mano Televisión Reloj Automotor Otro
Aporte D-pad 7.2.2. Navegación no táctil DEBER
Pantalla táctil 7.2.4. Entrada de pantalla táctil DEBER DEBER DEBERÍA
Micrófono 7.8.1. Micrófono DEBER DEBERÍA DEBER DEBER DEBERÍA
Sensores Acelerómetro 7.3.1 Acelerómetro DEBERÍA DEBERÍA DEBERÍA
GPS 7.3.3. GPS DEBERÍA DEBERÍA
Conectividad Wifi 7.4.2. IEEE 802.11 DEBERÍA DEBERÍA DEBERÍA DEBERÍA
Wi-Fi directo 7.4.2.1. Wi-Fi directo DEBERÍA DEBERÍA DEBERÍA
Bluetooth 7.4.3. Bluetooth DEBERÍA DEBER DEBER DEBER DEBERÍA
Bluetooth de baja energía 7.4.3. Bluetooth DEBERÍA DEBER DEBERÍA DEBERÍA DEBERÍA
radio celular 7.4.5. Capacidad mínima de red DEBERÍA
Modo host/periférico USB 7.7. USB DEBERÍA DEBERÍA DEBERÍA
Producción Puertos de salida de altavoz y/o audio 7.8.2. Salida de audio DEBER DEBER DEBER DEBER

3. Software

3.1. Compatibilidad de API administrada

El entorno de ejecución de bytecode administrado de Dalvik es el vehículo principal para las aplicaciones de Android. La interfaz de programación de aplicaciones (API) de Android es el conjunto de interfaces de la plataforma Android expuestas a las aplicaciones que se ejecutan en el entorno de tiempo de ejecución administrado. Las implementaciones de dispositivos DEBEN proporcionar implementaciones completas, incluidos todos los comportamientos documentados, de cualquier API documentada expuesta por el SDK de Android o cualquier API decorada con el marcador "@SystemApi" en el código fuente de Android ascendente.

Las implementaciones de dispositivos DEBEN admitir/preservar todas las clases, métodos y elementos asociados marcados por la anotación TestApi (@TestApi).

Las implementaciones de dispositivos NO DEBEN omitir ninguna API administrada, alterar interfaces o firmas de API, desviarse del comportamiento documentado o incluir no-ops, excepto donde lo permita específicamente esta Definición de compatibilidad.

Esta definición de compatibilidad permite que las implementaciones del dispositivo omitan algunos tipos de hardware para los que Android incluye API. En tales casos, las API DEBEN seguir presentes y comportarse de manera razonable. Consulte la sección 7 para conocer los requisitos específicos para este escenario.

3.1.1. Extensiones de Android

Android incluye la posibilidad de ampliar las API gestionadas manteniendo la misma versión de nivel de API. Las implementaciones de dispositivos Android DEBEN precargar la implementación AOSP de la biblioteca compartida ExtShared y los servicios ExtServices con versiones superiores o iguales a las versiones mínimas permitidas por cada nivel de API. Por ejemplo, las implementaciones de dispositivos con Android 7.0 que ejecutan el nivel de API 24 DEBEN incluir al menos la versión 1.

3.2. Compatibilidad con API suave

Además de las API administradas de la sección 3.1 , Android también incluye una importante API "suave" solo en tiempo de ejecución, en forma de cosas como intenciones, permisos y aspectos similares de las aplicaciones de Android que no se pueden aplicar en el momento de la compilación de la aplicación.

3.2.1. permisos

Los implementadores de dispositivos DEBEN admitir y hacer cumplir todas las constantes de permisos, tal como se documenta en la página de referencia de permisos . Tenga en cuenta que la sección 9 enumera los requisitos adicionales relacionados con el modelo de seguridad de Android.

3.2.2. Parámetros de construcción

Las API de Android incluyen una serie de constantes en la clase android.os.Build que pretenden describir el dispositivo actual. Para proporcionar valores coherentes y significativos en todas las implementaciones de dispositivos, la siguiente tabla incluye restricciones adicionales sobre los formatos de estos valores a los que DEBEN ajustarse las implementaciones de dispositivos.

Parámetro Detalles
VERSIÓN.LIBERACIÓN La versión del sistema Android actualmente en ejecución, en formato legible por humanos. Este campo DEBE tener uno de los valores de cadena definidos en 7.1 .
VERSIÓN.SDK La versión del sistema Android que se está ejecutando actualmente, en un formato accesible para el código de aplicación de terceros. Para Android 7.1, este campo DEBE tener el valor entero 7.1_INT.
VERSIÓN.SDK_INT La versión del sistema Android que se está ejecutando actualmente, en un formato accesible para el código de aplicación de terceros. Para Android 7.1, este campo DEBE tener el valor entero 7.1_INT.
VERSIÓN.INCREMENTAL Un valor elegido por el implementador del dispositivo que designa la compilación específica del sistema Android que se está ejecutando actualmente, en formato legible por humanos. Este valor NO DEBE reutilizarse para diferentes compilaciones disponibles para los usuarios finales. Un uso típico de este campo es indicar qué número de compilación o identificador de cambio de control de fuente se usó para generar la compilación. No hay requisitos sobre el formato específico de este campo, excepto que NO DEBE ser nulo o la cadena vacía ("").
JUNTA Un valor elegido por el implementador del dispositivo que identifica el hardware interno específico utilizado por el dispositivo, en formato legible por humanos. Un posible uso de este campo es indicar la revisión específica de la placa que alimenta el dispositivo. El valor de este campo DEBE codificarse como ASCII de 7 bits y coincidir con la expresión regular "^[a-zA-Z0-9_-]+$".
MARCA Un valor que refleja el nombre de marca asociado con el dispositivo como lo conocen los usuarios finales. DEBE estar en formato legible por humanos y DEBE representar al fabricante del dispositivo o la marca de la empresa bajo la cual se comercializa el dispositivo. El valor de este campo DEBE codificarse como ASCII de 7 bits y coincidir con la expresión regular "^[a-zA-Z0-9_-]+$".
SOPORTADO_ABIS El nombre del conjunto de instrucciones (tipo de CPU + convención ABI) del código nativo. Consulte la sección 3.3. Compatibilidad API nativa .
SUPPORTED_32_BIT_ABIS El nombre del conjunto de instrucciones (tipo de CPU + convención ABI) del código nativo. Consulte la sección 3.3. Compatibilidad API nativa .
SUPPORTED_64_BIT_ABIS El nombre del segundo conjunto de instrucciones (tipo de CPU + convención ABI) del código nativo. Consulte la sección 3.3. Compatibilidad API nativa .
CPU_ABI El nombre del conjunto de instrucciones (tipo de CPU + convención ABI) del código nativo. Consulte la sección 3.3. Compatibilidad API nativa .
CPU_ABI2 El nombre del segundo conjunto de instrucciones (tipo de CPU + convención ABI) del código nativo. Consulte la sección 3.3. Compatibilidad API nativa .
DISPOSITIVO Un valor elegido por el implementador del dispositivo que contiene el nombre de desarrollo o el nombre en clave que identifica la configuración de las características del hardware y el diseño industrial del dispositivo. El valor de este campo DEBE codificarse como ASCII de 7 bits y coincidir con la expresión regular "^[a-zA-Z0-9_-]+$". Este nombre de dispositivo NO DEBE cambiar durante la vida útil del producto.
HUELLA DACTILAR Una cadena que identifica de forma única esta compilación. DEBERÍA ser razonablemente legible por humanos. DEBE seguir esta plantilla:

$(MARCA)/$(PRODUCTO)/
$(DISPOSITIVO):$(VERSIÓN.LIBERACIÓN)/$(ID)/$(VERSIÓN.INCREMENTAL):$(TIPO)/$(ETIQUETAS)

Por ejemplo:

acme/miproducto/
mi dispositivo: 7.1 / LMYXX / 3359: depuración de usuario / claves de prueba

La huella digital NO DEBE incluir espacios en blanco. Si otros campos incluidos en la plantilla anterior tienen espacios en blanco, DEBEN reemplazarse en la huella digital de compilación con otro carácter, como el carácter de subrayado ("_"). El valor de este campo DEBE poder codificarse como ASCII de 7 bits.

HARDWARE El nombre del hardware (desde la línea de comando del kernel o /proc). DEBERÍA ser razonablemente legible por humanos. El valor de este campo DEBE codificarse como ASCII de 7 bits y coincidir con la expresión regular "^[a-zA-Z0-9_-]+$".
ANFITRIÓN Una cadena que identifica de forma única el host en el que se creó la compilación, en un formato legible por humanos. No hay requisitos sobre el formato específico de este campo, excepto que NO DEBE ser nulo o la cadena vacía ("").
IDENTIFICACIÓN Un identificador elegido por el implementador del dispositivo para referirse a una versión específica, en formato legible por humanos. Este campo puede ser el mismo que android.os.Build.VERSION.INCREMENTAL, pero DEBE ser un valor suficientemente significativo para que los usuarios finales distingan entre compilaciones de software. El valor de este campo DEBE codificarse como ASCII de 7 bits y coincidir con la expresión regular "^[a-zA-Z0-9._-]+$".
FABRICANTE El nombre comercial del fabricante de equipos originales (OEM) del producto. No hay requisitos sobre el formato específico de este campo, excepto que NO DEBE ser nulo o la cadena vacía ("").
MODELO Un valor elegido por el implementador del dispositivo que contiene el nombre del dispositivo conocido por el usuario final. Este DEBE ser el mismo nombre con el que se comercializa y vende el dispositivo a los usuarios finales. No hay requisitos sobre el formato específico de este campo, excepto que NO DEBE ser nulo o la cadena vacía ("").
PRODUCTO Un valor elegido por el implementador del dispositivo que contiene el nombre de desarrollo o el nombre en clave del producto específico (SKU) que DEBE ser único dentro de la misma marca. DEBE ser legible por humanos, pero no necesariamente para que lo vean los usuarios finales. El valor de este campo DEBE codificarse como ASCII de 7 bits y coincidir con la expresión regular "^[a-zA-Z0-9_-]+$". El nombre de este producto NO DEBE cambiar durante la vida útil del producto.
DE SERIE Un número de serie de hardware, que DEBE estar disponible y ser único en todos los dispositivos con el mismo MODELO y FABRICANTE. El valor de este campo DEBE codificarse como ASCII de 7 bits y coincidir con la expresión regular "^([a-zA-Z0-9]{6,20})$".
ETIQUETAS Una lista separada por comas de etiquetas elegidas por el implementador del dispositivo que distingue aún más la compilación. Este campo DEBE tener uno de los valores correspondientes a las tres configuraciones típicas de firma de la plataforma Android: release-keys, dev-keys, test-keys.
TIEMPO Un valor que representa la marca de tiempo de cuando se produjo la compilación.
ESCRIBE Un valor elegido por el implementador del dispositivo que especifica la configuración de tiempo de ejecución de la compilación. Este campo DEBE tener uno de los valores correspondientes a las tres configuraciones típicas de tiempo de ejecución de Android: usuario, depuración de usuario o eng.
USUARIO Un nombre o ID de usuario del usuario (o usuario automatizado) que generó la compilación. No hay requisitos sobre el formato específico de este campo, excepto que NO DEBE ser nulo o la cadena vacía ("").
PARCHE_SEGURIDAD Un valor que indica el nivel del parche de seguridad de una compilación. DEBE significar que la compilación no es vulnerable a ninguno de los problemas descritos en el Boletín de seguridad pública de Android designado. DEBE tener el formato [AAAA-MM-DD], que coincida con una cadena definida documentada en el Boletín de seguridad pública de Android o en el Aviso de seguridad de Android , por ejemplo, "2015-11-01".
BASE_OS Un valor que representa el parámetro FINGERPRINT de la compilación que, por lo demás, es idéntica a esta compilación, excepto por los parches proporcionados en el Boletín de seguridad pública de Android. DEBE informar el valor correcto y, si tal compilación no existe, informar una cadena vacía ("").

3.2.3. Compatibilidad de intención

3.2.3.1. Intenciones de aplicaciones principales

Las intenciones de Android permiten que los componentes de la aplicación soliciten funcionalidad de otros componentes de Android. El proyecto upstream de Android incluye una lista de aplicaciones consideradas aplicaciones básicas de Android, que implementa varios patrones de intención para realizar acciones comunes. Las aplicaciones principales de Android son:

  • Reloj de escritorio
  • Navegador
  • Calendario
  • Contactos
  • Galería
  • Búsqueda global
  • Lanzacohetes
  • Música
  • Ajustes

Las implementaciones de dispositivos DEBEN incluir las aplicaciones principales de Android, según corresponda, o un componente que implemente los mismos patrones de intención definidos por todos los componentes de Actividad o Servicio de estas aplicaciones principales de Android expuestas a otras aplicaciones, implícita o explícitamente, a través del atributo android:exported .

3.2.3.2. Resolución de intención

Dado que Android es una plataforma extensible, las implementaciones de dispositivos DEBEN permitir que cada patrón de intención al que se hace referencia en la sección 3.2.3.1 sea anulado por aplicaciones de terceros. La implementación de código abierto de Android upstream lo permite de forma predeterminada; los implementadores de dispositivos NO DEBEN otorgar privilegios especiales al uso de estos patrones de intenciones por parte de las aplicaciones del sistema, ni evitar que las aplicaciones de terceros se vinculen y asuman el control de estos patrones. Esta prohibición incluye específicamente, pero no se limita a, deshabilitar la interfaz de usuario "Selector" que permite al usuario seleccionar entre múltiples aplicaciones que manejan el mismo patrón de intención.

Las implementaciones de dispositivos DEBEN proporcionar una interfaz de usuario para que los usuarios modifiquen la actividad predeterminada para las intenciones.

Sin embargo, las implementaciones de dispositivos PUEDEN proporcionar actividades predeterminadas para patrones de URI específicos (p. ej., http://play.google.com) cuando la actividad predeterminada proporciona un atributo más específico para el URI de datos. Por ejemplo, un patrón de filtro de intención que especifica el URI de datos "http://www.android.com" es más específico que el patrón de intención central del navegador para "http://".

Android también incluye un mecanismo para que las aplicaciones de terceros declaren un comportamiento de vinculación de aplicaciones predeterminado autorizado para ciertos tipos de intentos de URI web. Cuando dichas declaraciones autorizadas se definen en los patrones de filtro de intenciones de una aplicación, las implementaciones de dispositivos:

  • DEBE intentar validar cualquier filtro de intención mediante la realización de los pasos de validación definidos en la especificación de Digital Asset Links tal como lo implementó el administrador de paquetes en el proyecto de código abierto de Android ascendente.
  • DEBE intentar la validación de los filtros de intenciones durante la instalación de la aplicación y establecer todos los filtros de intenciones de UIR validados correctamente como controladores de aplicaciones predeterminados para sus UIR.
  • PUEDE establecer filtros de intención de URI específicos como controladores de aplicaciones predeterminados para sus URI, si se verifican con éxito pero otros filtros de URI candidatos fallan en la verificación. Si la implementación de un dispositivo hace esto, DEBE proporcionar al usuario anulaciones de patrón por URI adecuadas en el menú de configuración.
  • DEBE proporcionar al usuario controles de enlaces de aplicaciones por aplicación en Configuración de la siguiente manera:
    • El usuario DEBE poder anular de manera integral el comportamiento predeterminado de los enlaces de la aplicación para que una aplicación sea: siempre abierta, siempre preguntar o nunca abierta, lo que debe aplicarse a todos los filtros de intención de URI candidatos por igual.
    • El usuario DEBE poder ver una lista de los filtros de intento de URI candidatos.
    • La implementación del dispositivo PUEDE brindarle al usuario la capacidad de anular filtros de intención de URI candidatos específicos que se verificaron con éxito, según el filtro de intención.
    • La implementación del dispositivo DEBE proporcionar a los usuarios la capacidad de ver y anular filtros de intención de URI candidatos específicos si la implementación del dispositivo permite que algunos filtros de intención de URI candidatos tengan éxito en la verificación, mientras que otros pueden fallar.

3.2.3.3. Espacios de nombres de intenciones

Las implementaciones de dispositivos NO DEBEN incluir ningún componente de Android que respete cualquier intención nueva o patrones de intención de transmisión utilizando una ACCIÓN, CATEGORÍA u otra cadena clave en el android. o com.android. espacio de nombres Los implementadores de dispositivos NO DEBEN incluir ningún componente de Android que respete cualquier intención nueva o patrones de intención de transmisión utilizando una ACCIÓN, CATEGORÍA u otra cadena clave en un espacio de paquete que pertenezca a otra organización. Los implementadores de dispositivos NO DEBEN alterar ni ampliar ninguno de los patrones de intención utilizados por las aplicaciones principales enumeradas en la sección 3.2.3.1 . Las implementaciones de dispositivos PUEDEN incluir patrones de intención utilizando espacios de nombres asociados clara y obviamente con su propia organización. Esta prohibición es análoga a la especificada para las clases del lenguaje Java en la sección 3.6 .

3.2.3.4. Intentos de difusión

Las aplicaciones de terceros dependen de la plataforma para transmitir ciertos intentos de notificarles los cambios en el entorno de hardware o software. Los dispositivos compatibles con Android DEBEN transmitir las intenciones de transmisión pública en respuesta a los eventos del sistema apropiados. Los intentos de transmisión se describen en la documentación del SDK.

3.2.3.5. Configuración predeterminada de la aplicación

Android incluye configuraciones que brindan a los usuarios una manera fácil de seleccionar sus aplicaciones predeterminadas, por ejemplo, para la pantalla de inicio o SMS. Cuando tenga sentido, las implementaciones de dispositivos DEBEN proporcionar un menú de configuración similar y ser compatibles con el patrón de filtro de intenciones y los métodos API descritos en la documentación del SDK, como se muestra a continuación.

Implementaciones de dispositivos:

  • DEBE respetar la intención de android.settings.HOME_SETTINGS de mostrar un menú de configuración de aplicación predeterminado para la pantalla de inicio, si la implementación del dispositivo informa android.software.home_screen.
  • DEBE proporcionar un menú de configuración que llamará a la intención android.provider.Telephony.ACTION_CHANGE_DEFAULT para mostrar un cuadro de diálogo para cambiar la aplicación de SMS predeterminada, si la implementación del dispositivo informa android.hardware.telephony.
  • DEBE respetar la intención de android.settings.NFC_PAYMENT_SETTINGS de mostrar un menú de configuración de aplicación predeterminado para Tocar y pagar, si la implementación del dispositivo informa android.hardware.nfc.hce.
  • DEBE respetar la intención de android.telecom.action.CHANGE_DEFAULT_DIALER de mostrar un cuadro de diálogo que permita al usuario cambiar la aplicación de teléfono predeterminada, si la implementación del dispositivo informa android.hardware.telephony .
  • DEBE respetar la intención android.settings.ACTION_VOICE_INPUT_SETTINGS cuando el dispositivo es compatible con VoiceInteractionService y mostrar un menú de configuración predeterminado de la aplicación para la entrada de voz y la asistencia.

3.3. Compatibilidad de API nativa

La compatibilidad del código nativo es un desafío. Por este motivo, se RECOMIENDA ENCARECIDAMENTE a los implementadores de dispositivos que utilicen las implementaciones de las bibliotecas que se enumeran a continuación del Proyecto de código abierto de Android anterior.

3.3.1. Interfaces binarias de aplicaciones

El código de bytes de Dalvik administrado puede llamar al código nativo proporcionado en el archivo .apk de la aplicación como un archivo ELF .so compilado para la arquitectura de hardware del dispositivo adecuado. Dado que el código nativo depende en gran medida de la tecnología del procesador subyacente, Android define una serie de interfaces binarias de aplicaciones (ABI) en el NDK de Android. Las implementaciones de dispositivos DEBEN ser compatibles con una o más ABI definidas y DEBEN implementar la compatibilidad con el NDK de Android, como se indica a continuación.

Si la implementación de un dispositivo incluye compatibilidad con una ABI de Android:

  • DEBE incluir soporte para el código que se ejecuta en el entorno administrado para llamar al código nativo, utilizando la semántica estándar de la interfaz nativa de Java (JNI).
  • DEBE ser compatible con la fuente (es decir, compatible con el encabezado) y compatible con el binario (para la ABI) con cada biblioteca requerida en la lista a continuación.
  • DEBE admitir el ABI de 32 bits equivalente si se admite cualquier ABI de 64 bits.
  • DEBE informar con precisión la interfaz binaria de aplicaciones (ABI) nativa compatible con el dispositivo, a través de los parámetros android.os.Build.SUPPORTED_ABIS, android.os.Build.SUPPORTED_32_BIT_ABIS y android.os.Build.SUPPORTED_64_BIT_ABIS, cada uno de ellos una lista separada por comas de ABI ordenados de mayor a menor preferencia.
  • DEBE informar, a través de los parámetros anteriores, solo aquellas ABI documentadas y descritas en la última versión de la documentación de administración de ABI de Android NDK , y DEBE incluir soporte para la extensión Advanced SIMD (también conocida como NEON).
  • DEBERÍA compilarse utilizando el código fuente y los archivos de encabezado disponibles en el proyecto de código abierto de Android ascendente.

Tenga en cuenta que las versiones futuras del NDK de Android pueden introducir soporte para ABI adicionales. Si la implementación de un dispositivo no es compatible con una ABI predefinida existente, NO DEBE informar que es compatible con ninguna ABI.

Las siguientes API de código nativo DEBEN estar disponibles para las aplicaciones que incluyen código nativo:

  • libandroid.so (soporte nativo de actividad de Android)
  • libc (biblioteca C)
  • libcamera2ndk.so
  • libdl (enlazador dinámico)
  • libEGL.so (administración de superficie nativa de OpenGL)
  • libGLESv1_CM.so (OpenGL ES 1.x)
  • libGLESv2.so (OpenGL ES 2.0)
  • libGLESv3.so (OpenGL ES 3.x)
  • libicui18n.so
  • libicuuc.so
  • libjnigraphics.so
  • liblog (registro de Android)
  • libmediandk.so (soporte de API de medios nativos)
  • libm (biblioteca de matemáticas)
  • libOpenMAXAL.so (compatible con OpenMAX AL 1.0.1)
  • libOpenSLES.so (soporte de audio OpenSL ES 1.0.1)
  • libRS.so
  • libstdc++ (Soporte mínimo para C++)
  • libvulkan.so (Vulkan)
  • libz (compresión Zlib)
  • interfaz JNI
  • Compatibilidad con OpenGL, como se describe a continuación

Para las bibliotecas nativas enumeradas anteriormente, la implementación del dispositivo NO DEBE agregar o eliminar las funciones públicas.

Las bibliotecas nativas no enumeradas anteriormente, pero implementadas y proporcionadas en AOSP, ya que las bibliotecas del sistema están reservadas y NO DEBEN estar expuestas a aplicaciones de terceros dirigidas al nivel de API 24 o superior.

Las implementaciones de dispositivos PUEDEN agregar bibliotecas que no sean AOSP y exponerlas directamente como una API a aplicaciones de terceros, pero las bibliotecas adicionales DEBERÍAN estar en /vendor/lib o /vendor/lib64 y DEBEN estar enumeradas en /vendor/etc/public.libraries.txt

Tenga en cuenta que las implementaciones de dispositivos DEBEN incluir libGLESv3.so y, a su vez, DEBEN exportar todos los símbolos de funciones de OpenGL ES 3.1 y Android Extension Pack , tal como se define en la versión NDK android-24. Aunque todos los símbolos deben estar presentes, solo las funciones correspondientes para las versiones y extensiones de OpenGL ES realmente compatibles con el dispositivo deben estar completamente implementadas.

3.3.1.1. Bibliotecas gráficas

Vulkan es una API multiplataforma de bajo costo para gráficos 3D de alto rendimiento. Las implementaciones de dispositivos, incluso si no incluyen compatibilidad con las API de Vulkan, DEBEN cumplir los siguientes requisitos:

  • Siempre DEBE proporcionar una biblioteca nativa llamada libvulkan.so que exporta símbolos de función para la API central de Vulkan 1.0, así como las VK_KHR_surface , VK_KHR_android_surface y VK_KHR_swapchain .

Implementaciones de dispositivos, si incluyen compatibilidad con las API de Vulkan:

  • DEBE informar, uno o más VkPhysicalDevices a través de la llamada vkEnumeratePhysicalDevices .
  • Cada VkPhysicalDevices enumerado DEBE implementar completamente la API de Vulkan 1.0.
  • DEBE informar los indicadores de función PackageManager#FEATURE_VULKAN_HARDWARE_LEVEL y PackageManager#FEATURE_VULKAN_HARDWARE_VERSION correctos.
  • DEBE enumerar capas, contenidas en bibliotecas nativas denominadas libVkLayer*.so en el directorio de bibliotecas nativas del paquete de la aplicación, a través de las funciones vkEnumerateInstanceLayerProperties y vkEnumerateDeviceLayerProperties en libvulkan.so
  • NO DEBE enumerar capas proporcionadas por bibliotecas fuera del paquete de la aplicación, ni proporcionar otras formas de rastrear o interceptar la API de Vulkan, a menos que la aplicación tenga el android:debuggable=”true” .

Implementaciones de dispositivos, si no incluyen compatibilidad con las API de Vulkan:

3.3.2. Compatibilidad con código nativo ARM de 32 bits

La arquitectura ARMv8 desaprueba varias operaciones de la CPU, incluidas algunas operaciones utilizadas en el código nativo existente. En los dispositivos ARM de 64 bits, las siguientes operaciones obsoletas DEBEN permanecer disponibles para el código ARM nativo de 32 bits, ya sea a través de la compatibilidad con CPU nativa o mediante la emulación de software:

  • Instrucciones SWP y SWPB
  • Instrucción FIJAR
  • Operaciones de barrera CP15ISB, CP15DSB y CP15DMB

Las versiones heredadas del NDK de Android usaban /proc/cpuinfo para descubrir funciones de CPU a partir de código nativo ARM de 32 bits. Para la compatibilidad con las aplicaciones creadas con este NDK, los dispositivos DEBEN incluir las siguientes líneas en /proc/cpuinfo cuando las aplicaciones ARM de 32 bits lo leen:

  • "Características: ", seguido de una lista de las funciones de CPU ARMv7 opcionales compatibles con el dispositivo.
  • "Arquitectura de CPU:", seguido de un número entero que describe la arquitectura ARM más compatible del dispositivo (p. ej., "8" para dispositivos ARMv8).

Estos requisitos solo se aplican cuando las aplicaciones ARM de 32 bits leen /proc/cpuinfo. Los dispositivos NO DEBEN alterar /proc/cpuinfo cuando lo leen aplicaciones ARM o no ARM de 64 bits.

3.4. Compatibilidad web

3.4.1. Compatibilidad con WebView

Los dispositivos Android Watch PUEDEN, pero todas las demás implementaciones de dispositivos DEBEN proporcionar una implementación completa de la API android.webkit.Webview.

La característica de la plataforma android.software.webview DEBE informarse en cualquier dispositivo que proporcione una implementación completa de la API android.webkit.WebView, y NO DEBE informarse en dispositivos sin una implementación completa de la API. La implementación de código abierto de Android usa código del Proyecto Chromium para implementar android.webkit.WebView . Debido a que no es factible desarrollar un conjunto de pruebas integral para un sistema de representación web, los implementadores de dispositivos DEBEN utilizar la compilación ascendente específica de Chromium en la implementación de WebView. Específicamente:

  • Las implementaciones del dispositivo android.webkit.WebView DEBEN basarse en la compilación Chromium del Proyecto de código abierto de Android ascendente para Android 7.1. Esta compilación incluye un conjunto específico de funciones y correcciones de seguridad para WebView.
  • La cadena de agente de usuario informada por WebView DEBE estar en este formato:

    Mozilla/5.0 (Linux; Android $(VERSION); $(MODEL) Build/$(BUILD); wv) AppleWebKit/537.36 (KHTML, como Gecko) Version/4.0 $(CHROMIUM_VER) Mobile Safari/537.36

    • El valor de la cadena $(VERSIÓN) DEBE ser el mismo que el valor de android.os.Build.VERSION.RELEASE.
    • El valor de la cadena $(MODEL) DEBE ser el mismo que el valor de android.os.Build.MODEL.
    • El valor de la cadena $(BUILD) DEBE ser el mismo que el valor de android.os.Build.ID.
    • El valor de la cadena $(CHROMIUM_VER) DEBE ser la versión de Chromium en el proyecto de código abierto de Android ascendente.
    • Las implementaciones de dispositivos PUEDEN omitir Mobile en la cadena de agente de usuario.

El componente WebView DEBERÍA incluir soporte para tantas funciones HTML5 como sea posible y, si es compatible, la función DEBERÍA cumplir con la especificación HTML5 .

3.4.2. Compatibilidad del navegador

Las implementaciones de Android Television, Watch y Android Automotive PUEDEN omitir una aplicación de navegador, pero DEBEN admitir los patrones de intención pública como se describe en la sección 3.2.3.1 . Todos los demás tipos de implementaciones de dispositivos DEBEN incluir una aplicación de navegador independiente para la navegación web general del usuario.

El Navegador independiente PUEDE estar basado en una tecnología de navegador que no sea WebKit. Sin embargo, incluso si se utiliza una aplicación de navegador alternativa, el componente android.webkit.WebView proporcionado a las aplicaciones de terceros DEBE estar basado en WebKit, como se describe en la sección 3.4.1 .

Las implementaciones PUEDEN enviar una cadena de agente de usuario personalizada en la aplicación de navegador independiente.

La aplicación de navegador independiente (ya sea que se base en la aplicación de navegador WebKit anterior o en un reemplazo de terceros) DEBERÍA incluir soporte para la mayor cantidad posible de HTML5 . Como mínimo, las implementaciones de dispositivos DEBEN admitir cada una de estas API asociadas con HTML5:

Además, las implementaciones de dispositivos DEBEN admitir la API de almacenamiento web HTML5/W3C y DEBERÍAN admitir la API IndexedDB de HTML5/W3C. Tenga en cuenta que a medida que los organismos de estándares de desarrollo web están en transición para favorecer a IndexedDB sobre el almacenamiento web, se espera que IndexedDB se convierta en un componente obligatorio en una versión futura de Android.

3.5. Compatibilidad de comportamiento de API

Los comportamientos de cada uno de los tipos de API (administrada, suave, nativa y web) deben ser coherentes con la implementación preferida del proyecto de código abierto de Android ascendente. Algunas áreas específicas de compatibilidad son:

  • Los dispositivos NO DEBEN cambiar el comportamiento o la semántica de una intención estándar.
  • Los dispositivos NO DEBEN alterar el ciclo de vida o la semántica del ciclo de vida de un tipo particular de componente del sistema (como Servicio, Actividad, Proveedor de contenido, etc.).
  • Los dispositivos NO DEBEN cambiar la semántica de un permiso estándar.

La lista anterior no es exhaustiva. Compatibility Test Suite (CTS) prueba partes significativas de la plataforma para compatibilidad de comportamiento, pero no todas. Es responsabilidad del implementador garantizar la compatibilidad de comportamiento con el proyecto de código abierto de Android. Por este motivo, los implementadores de dispositivos DEBERÍAN utilizar el código fuente disponible a través del Proyecto de código abierto de Android siempre que sea posible, en lugar de volver a implementar partes significativas del sistema.

3.6. Espacios de nombres de API

Android sigue las convenciones de espacio de nombres de paquetes y clases definidas por el lenguaje de programación Java. Para garantizar la compatibilidad con aplicaciones de terceros, los implementadores de dispositivos NO DEBEN realizar modificaciones prohibidas (consulte a continuación) en estos espacios de nombres de paquetes:

  • Java.*
  • javax.*
  • sol.*
  • androide.*
  • com.android.*

Las modificaciones prohibidas incluyen :

  • Las implementaciones de dispositivos NO DEBEN modificar las API expuestas públicamente en la plataforma Android cambiando ningún método o firma de clase, ni eliminando clases o campos de clase.
  • Los implementadores de dispositivos PUEDEN modificar la implementación subyacente de las API, pero tales modificaciones NO DEBEN afectar el comportamiento declarado y la firma en lenguaje Java de cualquier API expuesta públicamente.
  • Los implementadores de dispositivos NO DEBEN agregar ningún elemento expuesto públicamente (como clases o interfaces, o campos o métodos a clases o interfaces existentes) a las API anteriores.

Un "elemento expuesto públicamente" es cualquier construcción que no está decorada con el marcador "@hide" como se usa en el código fuente de Android ascendente. En otras palabras, los implementadores de dispositivos NO DEBEN exponer nuevas API ni alterar las API existentes en los espacios de nombres mencionados anteriormente. Los implementadores de dispositivos PUEDEN realizar modificaciones solo internas, pero esas modificaciones NO DEBEN publicitarse ni exponerse a los desarrolladores.

Los implementadores de dispositivos PUEDEN agregar API personalizadas, pero dichas API NO DEBEN estar en un espacio de nombres propiedad de otra organización o hacer referencia a ella. Por ejemplo, los implementadores de dispositivos NO DEBEN agregar API al espacio de nombres com.google.* o similar: solo Google puede hacerlo. Del mismo modo, Google NO DEBE agregar API a los espacios de nombres de otras empresas. Además, si la implementación de un dispositivo incluye API personalizadas fuera del espacio de nombres estándar de Android, esas API DEBEN empaquetarse en una biblioteca compartida de Android para que solo las aplicaciones que las usan explícitamente (a través del mecanismo <uses-library>) se vean afectadas por el mayor uso de memoria. de dichas API.

Si un implementador de dispositivos propone mejorar uno de los espacios de nombres de paquetes anteriores (como agregar una nueva funcionalidad útil a una API existente o agregar una nueva API), el implementador DEBERÍA visitar source.android.com y comenzar el proceso para aportar cambios y código, de acuerdo con la información en ese sitio.

Tenga en cuenta que las restricciones anteriores corresponden a convenciones estándar para nombrar API en el lenguaje de programación Java; esta sección simplemente tiene como objetivo reforzar esas convenciones y hacerlas vinculantes mediante su inclusión en esta Definición de compatibilidad.

3.7. Compatibilidad de tiempo de ejecución

Las implementaciones de dispositivos DEBEN admitir el formato Dalvik Executable (DEX) completo y la especificación y semántica del bytecode de Dalvik. Los implementadores de dispositivos DEBERÍAN utilizar ART, la implementación ascendente de referencia del formato ejecutable Dalvik y el sistema de gestión de paquetes de la implementación de referencia.

Las implementaciones de dispositivos DEBEN configurar los tiempos de ejecución de Dalvik para asignar memoria de acuerdo con la plataforma Android ascendente y como se especifica en la siguiente tabla. (Consulte la sección 7.1.1 para conocer las definiciones de tamaño y densidad de pantalla). Tenga en cuenta que los valores de memoria especificados a continuación se consideran valores mínimos y las implementaciones de dispositivos PUEDEN asignar más memoria por aplicación.

Diseño de pantalla Densidad de pantalla Memoria mínima de la aplicación
reloj androide 120 ppp (ldpi) 32MB
160 ppp (mdpi)
213 ppp (tvdpi)
240 ppp (hdpi) 36MB
280 ppp (280 ppp)
320 ppp (xhdpi) 48MB
360 ppp (360 ppp)
400 ppp (400 ppp) 56MB
420 ppp (420 ppp) 64MB
480 ppp (xxhdpi) 88MB
560 ppp (560 ppp) 112 MB
640 ppp (xxx hdpi) 154 MB
pequeño/normal 120 ppp (ldpi) 32MB
160 ppp (mdpi)
213 ppp (tvdpi) 48MB
240 ppp (hdpi)
280 ppp (280 ppp)
320 ppp (xhdpi) 80MB
360 ppp (360 ppp)
400 ppp (400 ppp) 96 MB
420 ppp (420 ppp) 112 MB
480 ppp (xxhdpi) 128 MB
560 ppp (560 ppp) 192 MB
640 ppp (xxx hdpi) 256 MB
largo 120 ppp (ldpi) 32MB
160 ppp (mdpi) 48MB
213 ppp (tvdpi) 80MB
240 ppp (hdpi)
280 ppp (280 ppp) 96 MB
320 ppp (xhdpi) 128 MB
360 ppp (360 ppp) 160 MB
400 ppp (400 ppp) 192 MB
420 ppp (420 ppp) 228 MB
480 ppp (xxhdpi) 256 MB
560 ppp (560 ppp) 384 MB
640 ppp (xxx hdpi) 512 MB
extra grande 120 ppp (ldpi) 48MB
160 ppp (mdpi) 80MB
213 ppp (tvdpi) 96 MB
240 ppp (hdpi)
280 ppp (280 ppp) 144 MB
320 ppp (xhdpi) 192 MB
360 ppp (360 ppp) 240 MB
400 ppp (400 ppp) 288 MB
420 ppp (420 ppp) 336 MB
480 ppp (xxhdpi) 384 MB
560 ppp (560 ppp) 576MB
640 ppp (xxx hdpi) 768 MB

3.8. Compatibilidad de la interfaz de usuario

3.8.1. Lanzador (pantalla de inicio)

Android incluye una aplicación de inicio (pantalla de inicio) y soporte para aplicaciones de terceros para reemplazar el inicio del dispositivo (pantalla de inicio). Las implementaciones de dispositivos que permiten que las aplicaciones de terceros reemplacen la pantalla de inicio del dispositivo DEBEN declarar la característica de la plataforma android.software.home_screen.

3.8.2. Widgets

Los widgets son opcionales para todas las implementaciones de dispositivos Android, pero DEBERÍAN ser compatibles con los dispositivos portátiles Android.

Android define un tipo de componente y la API y el ciclo de vida correspondientes que permiten que las aplicaciones expongan un "AppWidget" al usuario final, una función que se RECOMIENDA ENCARECIDAMENTE para que sea compatible con las implementaciones de dispositivos portátiles. Las implementaciones de dispositivos que admiten la incorporación de widgets en la pantalla de inicio DEBEN cumplir con los siguientes requisitos y declarar compatibilidad con la función de plataforma android.software.app_widgets.

  • Los lanzadores de dispositivos DEBEN incluir soporte incorporado para AppWidgets y exponer las posibilidades de la interfaz de usuario para agregar, configurar, ver y eliminar AppWidgets directamente dentro del Lanzador.
  • Las implementaciones de dispositivos DEBEN ser capaces de representar widgets de 4 x 4 en el tamaño de cuadrícula estándar. Consulte las Directrices de diseño de widgets de aplicaciones en la documentación del SDK de Android para obtener más detalles.
  • Las implementaciones de dispositivos que incluyen compatibilidad con la pantalla de bloqueo PUEDEN admitir widgets de aplicaciones en la pantalla de bloqueo.

3.8.3. Notificaciones

Android incluye API que permiten a los desarrolladores notificar a los usuarios sobre eventos notables utilizando las funciones de hardware y software del dispositivo.

Algunas API permiten que las aplicaciones realicen notificaciones o llamen la atención mediante hardware, específicamente sonido, vibración y luz. Las implementaciones de dispositivos DEBEN admitir notificaciones que usan funciones de hardware, como se describe en la documentación del SDK, y en la medida de lo posible con el hardware de implementación del dispositivo. Por ejemplo, si la implementación de un dispositivo incluye un vibrador, DEBE implementar correctamente las API de vibración. Si la implementación de un dispositivo carece de hardware, las API correspondientes DEBEN implementarse sin operaciones. Este comportamiento se detalla más en la sección 7 .

Además, la implementación DEBE representar correctamente todos los recursos (iconos, archivos de animación, etc.) previstos en las API o en la guía de estilo de iconos de la barra de estado/sistema, que en el caso de un dispositivo Android Television incluye la posibilidad de no mostrar el notificaciones Los implementadores de dispositivos PUEDEN proporcionar una experiencia de usuario alternativa para las notificaciones que la proporcionada por la implementación de código abierto de Android de referencia; sin embargo, dichos sistemas de notificación alternativos DEBEN admitir los recursos de notificación existentes, como se indicó anteriormente.

Las implementaciones de Android Automotive PUEDEN administrar la visibilidad y el tiempo de las notificaciones para mitigar la distracción del conductor, pero DEBEN mostrar notificaciones que usan CarExtender cuando las aplicaciones lo solicitan.

Android incluye soporte para varias notificaciones, como:

  • Notificaciones enriquecidas . Vistas interactivas para notificaciones en curso.
  • Notificaciones de alerta . Los usuarios de vistas interactivas pueden actuar o descartar sin salir de la aplicación actual.
  • Notificaciones de pantalla de bloqueo . Notificaciones que se muestran en una pantalla de bloqueo con control granular de visibilidad.

Las implementaciones de dispositivos Android, cuando tales notificaciones se hacen visibles, DEBEN ejecutar correctamente las notificaciones Rich y Heads-up e incluir el título/nombre, ícono, texto como se documenta en las API de Android .

Android incluye las API del servicio de escucha de notificaciones que permiten que las aplicaciones (una vez que el usuario las haya habilitado explícitamente) reciban una copia de todas las notificaciones a medida que se publican o actualizan. Las implementaciones de dispositivos DEBEN enviar notificaciones correcta y rápidamente en su totalidad a todos los servicios de escucha instalados y habilitados por el usuario, incluidos todos los metadatos adjuntos al objeto de notificación.

Las implementaciones de dispositivos portátiles DEBEN admitir los comportamientos de actualización, eliminación, respuesta y agrupación de notificaciones, tal como se describe en esta sección .

Además, las implementaciones de dispositivos portátiles DEBEN proporcionar:

  • La capacidad de controlar las notificaciones directamente en el tono de notificación.
  • La posibilidad visual de activar el panel de control en el tono de notificación.
  • La capacidad de BLOQUEAR, SILENCIAR y REINICIAR las preferencias de notificación de un paquete, tanto en el panel de control en línea como en la aplicación de configuración.

Las 6 subclases directas de la Notification.Style class DEBEN admitirse como se describe en los documentos del SDK .

Las implementaciones de dispositivos que admiten la función DND (No molestar) DEBEN cumplir los siguientes requisitos:

  • DEBE implementar una actividad que responda a la intención ACTION_NOTIFICATION_POLICY_ACCESS_SETTINGS , que para implementaciones con UI_MODE_TYPE_NORMAL DEBE ser una actividad en la que el usuario pueda otorgar o denegar el acceso de la aplicación a las configuraciones de la política DND.
  • DEBE, para cuando la implementación del dispositivo ha proporcionado un medio para que el usuario otorgue o deniegue aplicaciones de terceros para acceder a la configuración de la política DND, muestre las reglas DND automáticas creadas por las aplicaciones junto con las reglas predefinidas y creadas por el usuario.
  • DEBE respetar los valores de los efectos visuales suppressedVisualEffects que se pasan a través de NotificationManager.Policy y, si una aplicación ha configurado cualquiera de los indicadores SUPPRESSED_EFFECT_SCREEN_OFF o SUPPRESSED_EFFECT_SCREEN_ON, DEBE indicar al usuario que los efectos visuales se suprimen en el menú de configuración de DND.

Android incluye API que permiten a los desarrolladores incorporar la búsqueda en sus aplicaciones y exponer los datos de su aplicación en la búsqueda del sistema global. En términos generales, esta funcionalidad consta de una única interfaz de usuario para todo el sistema que permite a los usuarios ingresar consultas, muestra sugerencias a medida que los usuarios escriben y muestra los resultados. Las API de Android permiten a los desarrolladores reutilizar esta interfaz para proporcionar búsquedas dentro de sus propias aplicaciones y permitir que los desarrolladores proporcionen resultados a la interfaz de usuario de búsqueda global común.

Las implementaciones de dispositivos Android DEBERÍAN incluir búsqueda global, una única interfaz de usuario de búsqueda compartida en todo el sistema capaz de ofrecer sugerencias en tiempo real en respuesta a la entrada del usuario. Las implementaciones de dispositivos DEBERÍAN implementar las API que permiten a los desarrolladores reutilizar esta interfaz de usuario para proporcionar búsqueda dentro de sus propias aplicaciones. Las implementaciones de dispositivos que implementan la interfaz de búsqueda global DEBEN implementar las API que permiten que las aplicaciones de terceros agreguen sugerencias al cuadro de búsqueda cuando se ejecuta en modo de búsqueda global. Si no se instalan aplicaciones de terceros que hagan uso de esta funcionalidad, el comportamiento predeterminado DEBERÍA ser mostrar resultados y sugerencias del motor de búsqueda web.

Las implementaciones de dispositivos Android DEBERÍAN, y las implementaciones de Android Automotive DEBEN, implementar un asistente en el dispositivo para manejar la acción de Asistencia .

Android también incluye las API de asistencia para permitir que las aplicaciones elijan cuánta información del contexto actual se comparte con el asistente en el dispositivo. Las implementaciones de dispositivos que admiten la acción de asistencia DEBEN indicar claramente al usuario final cuándo se comparte el contexto mostrando una luz blanca alrededor de los bordes de la pantalla. Para garantizar una visibilidad clara para el usuario final, la indicación DEBE cumplir o superar la duración y el brillo de la implementación del Proyecto de código abierto de Android.

Esta indicación PUEDE estar deshabilitada de forma predeterminada para las aplicaciones preinstaladas que usan la API Assist y VoiceInteractionService, si se cumplen todos los requisitos siguientes:

  • La aplicación preinstalada DEBE solicitar que se comparta el contexto solo cuando el usuario invocó la aplicación por uno de los siguientes medios y la aplicación se está ejecutando en primer plano:

    • invocación de palabras clave
    • entrada de la tecla/botón/gesto de navegación ASSIST
  • La implementación del dispositivo DEBE proporcionar una posibilidad para habilitar la indicación, a menos de dos navegaciones de distancia (el menú de configuración de la aplicación asistente y la entrada de voz predeterminada) sección 3.2.3.5 .

3.8.5. tostadas

Las aplicaciones pueden usar la API "Toast" para mostrar cadenas cortas no modales al usuario final que desaparecen después de un breve período de tiempo. Las implementaciones de dispositivos DEBEN mostrar Toasts de las aplicaciones a los usuarios finales de alguna manera de alta visibilidad.

3.8.6. Temas

Android proporciona "temas" como un mecanismo para que las aplicaciones apliquen estilos en toda una actividad o aplicación.

Android incluye una familia de temas "Holo" como un conjunto de estilos definidos para que los desarrolladores de aplicaciones los usen si desean igualar la apariencia del tema Holo según lo define el SDK de Android. Las implementaciones de dispositivos NO DEBEN alterar ninguno de los atributos del tema Holo expuestos a las aplicaciones.

Android incluye una familia de temas "Material" como un conjunto de estilos definidos para que los desarrolladores de aplicaciones los usen si desean igualar la apariencia del tema de diseño en la amplia variedad de diferentes tipos de dispositivos Android. Las implementaciones de dispositivos DEBEN admitir la familia de temas "Material" y NO DEBEN alterar ninguno de los atributos del tema Material o sus activos expuestos a las aplicaciones.

Android también incluye una familia de temas "Predeterminada del dispositivo" como un conjunto de estilos definidos para que los desarrolladores de aplicaciones los usen si desean hacer coincidir la apariencia del tema del dispositivo según lo definido por el implementador del dispositivo. Las implementaciones de dispositivos PUEDEN modificar los atributos del tema predeterminado del dispositivo expuestos a las aplicaciones.

Android admite una variante de tema con barras de sistema translúcidas, lo que permite a los desarrolladores de aplicaciones llenar el área detrás de la barra de estado y navegación con el contenido de su aplicación. Para permitir una experiencia de desarrollador consistente en esta configuración, es importante que el estilo del icono de la barra de estado se mantenga en diferentes implementaciones de dispositivos. Por lo tanto, las implementaciones de dispositivos Android DEBEN usar blanco para los íconos de estado del sistema (como la intensidad de la señal y el nivel de la batería) y las notificaciones emitidas por el sistema, a menos que el ícono indique un estado problemático o que una aplicación solicite una barra de estado clara usando la bandera SYSTEM_UI_FLAG_LIGHT_STATUS_BAR. Cuando una aplicación solicita una barra de estado clara, las implementaciones de dispositivos Android DEBEN cambiar el color de los íconos de estado del sistema a negro (para obtener detalles, consulte R.style ).

3.8.7. Fondos de pantalla vivos

Android define un tipo de componente y la API y el ciclo de vida correspondientes que permiten que las aplicaciones expongan uno o más "Fondos de pantalla en vivo" al usuario final. Los fondos de pantalla en vivo son animaciones, patrones o imágenes similares con capacidades de entrada limitadas que se muestran como un fondo de pantalla, detrás de otras aplicaciones.

Se considera que el hardware es capaz de ejecutar fondos de pantalla en vivo de manera confiable si puede ejecutar todos los fondos de pantalla en vivo, sin limitaciones en la funcionalidad, a una velocidad de cuadros razonable y sin efectos adversos en otras aplicaciones. Si las limitaciones en el hardware hacen que los fondos de pantalla y/o las aplicaciones se bloqueen, funcionen mal, consuman demasiada CPU o energía de la batería, o se ejecuten a velocidades de cuadro inaceptablemente bajas, se considera que el hardware es incapaz de ejecutar fondos de pantalla en vivo. Como ejemplo, algunos fondos de pantalla en vivo pueden usar un contexto OpenGL 2.0 o 3.x para representar su contenido. El fondo de pantalla en vivo no se ejecutará de manera confiable en hardware que no admita múltiples contextos OpenGL porque el uso de un fondo de pantalla en vivo de un contexto OpenGL puede entrar en conflicto con otras aplicaciones que también usan un contexto OpenGL.

Las implementaciones de dispositivos capaces de ejecutar fondos de pantalla en vivo de manera confiable, como se describe anteriormente, DEBERÍAN implementar fondos de pantalla en vivo y, cuando se implementen, DEBEN informar el indicador de función de la plataforma android.software.live_wallpaper.

3.8.8. Cambio de actividad

Como la tecla de navegación de funciones recientes es OPCIONAL, el requisito para implementar la pantalla de descripción general es OPCIONAL para implementaciones de Android Watch y Android Automotive, y RECOMENDADO para dispositivos Android Television. Todavía DEBERÍA haber un método para cambiar entre actividades en las implementaciones de Android Automotive.

El código fuente de Android ascendente incluye la pantalla de descripción general , una interfaz de usuario a nivel del sistema para cambiar de tarea y mostrar actividades y tareas a las que se accedió recientemente mediante una imagen en miniatura del estado gráfico de la aplicación en el momento en que el usuario abandonó la aplicación por última vez. Las implementaciones de dispositivos, incluida la tecla de navegación de funciones recientes, como se detalla en la sección 7.2.3, PUEDEN alterar la interfaz, pero DEBEN cumplir con los siguientes requisitos:

  • DEBE admitir al menos hasta 20 actividades mostradas.
  • DEBERÍA mostrar al menos el título de 4 actividades a la vez.
  • DEBE implementar el comportamiento de fijación de pantalla y proporcionar al usuario un menú de configuración para alternar la función.
  • DEBERÍA mostrar el color de resaltado, el icono y el título de la pantalla en los últimos.
  • DEBERÍA mostrar una posibilidad de cierre ("x") pero PUEDE retrasar esto hasta que el usuario interactúe con las pantallas.
  • DEBERÍA implementar un atajo para cambiar fácilmente a la actividad anterior
  • PUEDE mostrar los afiliados recientes como un grupo que se mueve junto.
  • DEBERÍA desencadenar la acción de cambio rápido entre las dos aplicaciones utilizadas más recientemente, cuando la tecla de función reciente se toca dos veces.
  • DEBERÍA activar el modo multiventana de pantalla dividida, si es compatible, cuando se presiona prolongadamente la tecla de funciones recientes.

Se RECOMIENDA ENCARECIDAMENTE que las implementaciones de dispositivos utilicen la interfaz de usuario de Android anterior (o una interfaz similar basada en miniaturas) para la pantalla de descripción general.

3.8.9. Gestión de entrada

Android incluye compatibilidad con Input Management y compatibilidad con editores de métodos de entrada de terceros. Las implementaciones de dispositivos que permiten a los usuarios usar métodos de entrada de terceros en el dispositivo DEBEN declarar la característica de la plataforma android.software.input_methods y admitir las API de IME como se define en la documentación del SDK de Android.

Las implementaciones de dispositivos que declaran la función android.software.input_methods DEBEN proporcionar un mecanismo al que pueda acceder el usuario para agregar y configurar métodos de entrada de terceros. Las implementaciones de dispositivos DEBEN mostrar la interfaz de configuración en respuesta a la intención android.settings.INPUT_METHOD_SETTINGS.

3.8.10. Control multimedia de la pantalla de bloqueo

La API de cliente de control remoto está obsoleta en Android 5.0 en favor de la plantilla de notificación de medios que permite que las aplicaciones de medios se integren con los controles de reproducción que se muestran en la pantalla de bloqueo. Las implementaciones de dispositivos que admiten una pantalla de bloqueo, a menos que una implementación de Android Automotive o Watch, DEBEN mostrar las notificaciones de la pantalla de bloqueo, incluida la plantilla de notificación de medios.

3.8.11. Protectores de pantalla (anteriormente Dreams)

Android incluye compatibilidad con protectores de pantalla interactivos , anteriormente denominados Dreams. Los protectores de pantalla permiten a los usuarios interactuar con las aplicaciones cuando un dispositivo conectado a una fuente de alimentación está inactivo o acoplado a una base de escritorio. Los dispositivos Android Watch PUEDEN implementar protectores de pantalla, pero otros tipos de implementaciones de dispositivos DEBERÍAN incluir soporte para protectores de pantalla y proporcionar una opción de configuración para que los usuarios configuren protectores de pantalla en respuesta a la intención de android.settings.DREAM_SETTINGS .

3.8.12. Ubicación

Cuando un dispositivo tiene un sensor de hardware (por ejemplo, GPS) que es capaz de proporcionar las coordenadas de ubicación, los modos de ubicación DEBEN mostrarse en el menú Ubicación dentro de Configuración.

3.8.13. Unicode y fuente

Android incluye soporte para los caracteres emoji definidos en Unicode 9.0 . Todas las implementaciones de dispositivos DEBEN ser capaces de representar estos caracteres emoji en glifos de color y cuando las implementaciones de dispositivos Android incluyen un IME, DEBERÍA proporcionar un método de entrada al usuario para estos caracteres emoji.

Los dispositivos portátiles Android DEBERÍAN admitir el tono de piel y diversos emojis familiares como se especifica en el Informe técnico de Unicode n.° 51 .

Android incluye soporte para la fuente Roboto 2 con diferentes pesos: sans-serif-thin, sans-serif-light, sans-serif-medium, sans-serif-black, sans-serif-condensed, sans-serif-condensed-light, que DEBEN incluirse todos los idiomas disponibles en el dispositivo y la cobertura completa de Unicode 7.0 de latín, griego y cirílico, incluidos los rangos latinos extendidos A, B, C y D, y todos los glifos en el bloque de símbolos de moneda de Unicode 7.0.

3.8.14. Multiventanas

La implementación de un dispositivo PUEDE optar por no implementar ningún modo de múltiples ventanas, pero si tiene la capacidad de mostrar múltiples actividades al mismo tiempo, DEBE implementar dichos modos de múltiples ventanas de acuerdo con los comportamientos de la aplicación y las API descritas en el Documentación de compatibilidad con el modo multiventana de Android SDK y cumplir con los siguientes requisitos:

  • Las aplicaciones pueden indicar si son capaces de operar en modo multiventana en el archivo AndroidManifest.xml, ya sea explícitamente a través del atributo android:resizeableActivity o implícitamente al tener targetSdkVersion > 24. Las aplicaciones que configuran explícitamente este atributo como falso en su manifiesto DEBEN no se iniciará en el modo multiventana. Las aplicaciones que no establecen el atributo en su archivo de manifiesto (targetSdkVersion < 24) se pueden iniciar en el modo de ventanas múltiples, pero el sistema DEBE advertir que es posible que la aplicación no funcione como se esperaba en el modo de ventanas múltiples.
  • Las implementaciones de dispositivos NO DEBEN ofrecer modo de pantalla dividida o de forma libre si la altura y el ancho de la pantalla son inferiores a 440 dp.
  • Las implementaciones de dispositivos con tamaño de pantalla xlarge DEBERÍAN admitir el modo de forma libre.
  • Las implementaciones de dispositivos Android Television DEBEN admitir el modo de ventana múltiple de imagen en imagen (PIP) y colocar la ventana múltiple de PIP en la esquina superior derecha cuando PIP está activado.
  • Las implementaciones de dispositivos compatibles con múltiples ventanas en modo PIP DEBEN asignar al menos 240x135 dp para la ventana PIP.
  • Si se admite el modo de ventana múltiple PIP, DEBE utilizarse la tecla KeyEvent.KEYCODE_WINDOW para controlar la ventana PIP; de lo contrario, la clave DEBE estar disponible para la actividad en primer plano.

3.9. Administración de dispositivos

Android incluye funciones que permiten que las aplicaciones conscientes de la seguridad realicen funciones de administración de dispositivos a nivel del sistema, como hacer cumplir las políticas de contraseñas o realizar un borrado remoto, a través de la API de administración de dispositivos de Android . Las implementaciones de dispositivos DEBEN proporcionar una implementación de la clase DevicePolicyManager . Las implementaciones de dispositivos que admitan una pantalla de bloqueo segura DEBEN implementar la gama completa de políticas de administración de dispositivos definidas en la documentación del SDK de Android e informar la característica de la plataforma android.software.device_admin.

3.9.1 Aprovisionamiento de dispositivos

3.9.1.1 Aprovisionamiento del propietario del dispositivo

Si la implementación de un dispositivo declara la función android.software.device_admin , DEBE implementar el aprovisionamiento de la aplicación de propietario del dispositivo de una aplicación de cliente de política de dispositivos (DPC) como se indica a continuación:

Las implementaciones de dispositivos PUEDEN tener una aplicación preinstalada que realiza funciones de administración del dispositivo, pero esta aplicación NO DEBE configurarse como la aplicación del propietario del dispositivo sin el consentimiento explícito o la acción del usuario o el administrador del dispositivo.

3.9.1.2 Aprovisionamiento de perfiles gestionados

Si la implementación de un dispositivo declara android.software.managed_users, DEBE ser posible inscribir una aplicación de controlador de políticas de dispositivos (DPC) como propietaria de un nuevo perfil administrado .

La experiencia del usuario del proceso de aprovisionamiento de perfiles administrados (el flujo iniciado por android.app.action.PROVISION_MANAGED_PROFILE ) DEBE alinearse con la implementación de AOSP.

Las implementaciones de dispositivos DEBEN proporcionar las siguientes prestaciones de usuario dentro de la interfaz de usuario de Configuración para indicar al usuario cuándo una función particular del sistema ha sido deshabilitada por el controlador de políticas de dispositivos (DPC):

  • Un ícono consistente u otra posibilidad de usuario (por ejemplo, el ícono de información de AOSP ascendente) para representar cuándo un administrador de dispositivos restringe una configuración en particular.
  • Un breve mensaje de explicación, proporcionado por el administrador del dispositivo a través de setShortSupportMessage .
  • El icono de la aplicación DPC.

3.9.2 Compatibilidad con perfiles gestionados

Los dispositivos compatibles con perfiles administrados son aquellos dispositivos que:

Los dispositivos compatibles con perfiles administrados DEBEN:

  • Declare el indicador de características de la plataforma android.software.managed_users .
  • Admite perfiles administrados a través de las API de android.app.admin.DevicePolicyManager .
  • Permitir la creación de un único perfil gestionado .
  • Utilice una insignia de icono (similar a la insignia de trabajo ascendente de AOSP) para representar las aplicaciones y los widgets administrados y otros elementos de la interfaz de usuario con insignia, como Recientes y notificaciones.
  • Muestre un ícono de notificación (similar a la insignia de trabajo ascendente de AOSP) para indicar cuándo el usuario está dentro de una aplicación de perfil administrado.
  • Muestre un brindis que indique que el usuario está en el perfil administrado siempre y cuando el dispositivo se active (ACTION_USER_PRESENT) y la aplicación en primer plano esté dentro del perfil administrado.
  • Cuando exista un perfil administrado, muestre una posibilidad visual en el "Selector" de intenciones para permitir que el usuario reenvíe la intención del perfil administrado al usuario principal o viceversa, si está habilitado por Device Policy Controller.
  • Cuando exista un perfil administrado, exponga las siguientes prestaciones de usuario tanto para el usuario principal como para el perfil administrado:
    • Contabilidad separada para batería, ubicación, datos móviles y uso de almacenamiento para el usuario principal y el perfil administrado.
    • Gestión independiente de aplicaciones VPN instaladas dentro del usuario principal o perfil gestionado.
    • Gestión independiente de aplicaciones instaladas dentro del usuario principal o perfil gestionado.
    • Gestión independiente de cuentas dentro del usuario principal o perfil gestionado.
  • Asegúrese de que el marcador preinstalado, los contactos y las aplicaciones de mensajería puedan buscar y consultar la información de la persona que llama desde el perfil administrado (si existe) junto con la del perfil principal, si Device Policy Controller lo permite. Cuando los contactos del perfil administrado se muestran en el registro de llamadas preinstalado, la interfaz de usuario de llamadas entrantes, las notificaciones de llamadas perdidas y en curso, los contactos y las aplicaciones de mensajería, DEBEN tener la misma insignia que se usa para indicar las aplicaciones de perfil administrado.
  • DEBE asegurarse de que cumple con todos los requisitos de seguridad aplicables a un dispositivo con varios usuarios habilitados (consulte la sección 9.5 ), aunque el perfil administrado no se cuente como otro usuario además del usuario principal.
  • Admita la capacidad de especificar una pantalla de bloqueo separada que cumpla con los siguientes requisitos para otorgar acceso a las aplicaciones que se ejecutan en un perfil administrado.

3.10. Accesibilidad

Android proporciona una capa de accesibilidad que ayuda a los usuarios con discapacidades a navegar por sus dispositivos más fácilmente. Además, Android proporciona API de plataforma que permiten que las implementaciones de servicios de accesibilidad reciban devoluciones de llamada para eventos del sistema y del usuario y generen mecanismos de retroalimentación alternativos, como texto a voz, retroalimentación háptica y navegación con trackball/d-pad.

Las implementaciones de dispositivos incluyen los siguientes requisitos:

  • Las implementaciones de Android Automotive DEBERÍAN proporcionar una implementación del marco de accesibilidad de Android coherente con la implementación predeterminada de Android.
  • Las implementaciones de dispositivos (excepto Android Automotive) DEBEN proporcionar una implementación del marco de accesibilidad de Android coherente con la implementación predeterminada de Android.
  • Las implementaciones de dispositivos (excepto Android Automotive) DEBEN admitir implementaciones de servicios de accesibilidad de terceros a través de las API de android.accessibilityservice .
  • Las implementaciones de dispositivos (Android Automotive excluido) DEBEN generar AccessibilityEvents y entregar estos eventos a todas las implementaciones de AccessibilityService registradas de manera consistente con la implementación predeterminada de Android.
  • Las implementaciones de dispositivos (dispositivos Android Automotive y Android Watch sin salida de audio excluida) DEBEN proporcionar un mecanismo accesible para el usuario para habilitar y deshabilitar los servicios de accesibilidad, y DEBEN mostrar esta interfaz en respuesta a la intención android.provider.Settings.ACTION_ACCESSIBILITY_SETTINGS.

  • Se RECOMIENDAN ENCARECIDAMENTE las implementaciones de dispositivos Android con salida de audio para proporcionar implementaciones de servicios de accesibilidad en el dispositivo comparables o superiores a la funcionalidad de los servicios de accesibilidad TalkBack** y Switch Access (https://github.com/google/talkback).

  • Los dispositivos Android Watch con salida de audio DEBERÍAN proporcionar implementaciones de un servicio de accesibilidad en el dispositivo comparable o superior a la funcionalidad del servicio de accesibilidad TalkBack (https://github.com/google/talkback).
  • Las implementaciones de dispositivos DEBERÍAN proporcionar un mecanismo en el flujo de configuración listo para usar para que los usuarios habiliten los servicios de accesibilidad relevantes, así como opciones para ajustar el tamaño de fuente, el tamaño de visualización y los gestos de ampliación.

** Para idiomas admitidos por Text-to-speech.

Además, tenga en cuenta que si hay un servicio de accesibilidad precargado, DEBE ser una aplicación {directBootAware} con reconocimiento de arranque directo si el dispositivo tiene almacenamiento cifrado mediante el cifrado basado en archivos (FBE).

3.11. Texto a voz

Android incluye API que permiten que las aplicaciones utilicen servicios de texto a voz (TTS) y permite que los proveedores de servicios proporcionen implementaciones de servicios TTS. Las implementaciones de dispositivos que informan la función android.hardware.audio.output DEBEN cumplir con estos requisitos relacionados con el marco de Android TTS .

Implementaciones de Android Automotive:

  • DEBE ser compatible con las API del marco de Android TTS.
  • PUEDE admitir la instalación de motores TTS de terceros. Si es compatible, los socios DEBEN proporcionar una interfaz accesible para el usuario que le permita seleccionar un motor TTS para usar a nivel del sistema.

Todas las demás implementaciones de dispositivos:

  • DEBE ser compatible con las API del marco de trabajo de TTS de Android y DEBE incluir un motor de TTS compatible con los idiomas disponibles en el dispositivo. Tenga en cuenta que el software de código abierto de Android ascendente incluye una implementación de motor TTS con todas las funciones.
  • DEBE admitir la instalación de motores TTS de terceros.
  • DEBE proporcionar una interfaz accesible para el usuario que les permita seleccionar un motor TTS para usar a nivel del sistema.

3.12. Marco de entrada de TV

Android Television Input Framework (TIF) simplifica la entrega de contenido en vivo a los dispositivos Android Television. TIF proporciona una API estándar para crear módulos de entrada que controlan los dispositivos Android Television. Las implementaciones de dispositivos Android Television DEBEN ser compatibles con TV Input Framework.

Las implementaciones de dispositivos que admiten TIF DEBEN declarar la característica de la plataforma android.software.live_tv.

3.12.1. aplicación de televisión

Cualquier implementación de dispositivo que declare soporte para Live TV DEBE tener una aplicación de TV instalada (aplicación de TV). El proyecto de código abierto de Android proporciona una implementación de la aplicación de TV.

La aplicación de TV DEBE proporcionar facilidades para instalar y usar canales de TV y cumplir con los siguientes requisitos:

  • Las implementaciones de dispositivos DEBEN permitir la instalación y administración de entradas basadas en TIF de terceros (entradas de terceros).
  • Las implementaciones de dispositivos PUEDEN proporcionar una separación visual entre las entradas basadas en TIF preinstaladas (entradas instaladas) y las entradas de terceros.
  • Las implementaciones de dispositivos NO DEBEN mostrar las entradas de terceros más de una sola acción de navegación fuera de la aplicación de TV (es decir, expandir una lista de entradas de terceros desde la aplicación de TV).

3.12.1.1. Guía electrónica de programas

Las implementaciones de dispositivos Android Television DEBEN mostrar una superposición informativa e interactiva, que DEBE incluir una guía de programación electrónica (EPG) generada a partir de los valores en los campos TvContract.Programs . La EPG DEBE cumplir con los siguientes requisitos:

  • La EPG DEBE mostrar información de todas las entradas instaladas y entradas de terceros.
  • La EPG PUEDE proporcionar una separación visual entre las entradas instaladas y las entradas de terceros.
  • Se RECOMIENDA ENCARECIDAMENTE que la EPG muestre las entradas instaladas y las entradas de terceros con igual prominencia. La EPG NO DEBE mostrar las entradas de terceros a más de una sola acción de navegación de las entradas instaladas en la EPG.
  • En el cambio de canal, las implementaciones del dispositivo DEBEN mostrar datos EPG para el programa que se está reproduciendo actualmente.

3.12.1.2. Navegación

La aplicación de TV DEBE permitir la navegación para las siguientes funciones a través de las teclas D-pad, Atrás e Inicio en los dispositivos de entrada del dispositivo Android Television (es decir, control remoto, aplicación de control remoto o controlador de juegos):

  • Cambio de canales de televisión
  • Apertura de EPG
  • Configuración y ajuste de entradas basadas en TIF de terceros
  • Apertura del menú de configuración

La aplicación de TV DEBE pasar eventos clave a las entradas HDMI a través de CEC.

3.12.1.3. Enlace de aplicación de entrada de TV

Las implementaciones de dispositivos Android Television DEBEN admitir la vinculación de aplicaciones de entrada de TV , lo que permite que todas las entradas brinden vínculos de actividad de la actividad actual a otra actividad (es decir, un vínculo de la programación en vivo al contenido relacionado). La aplicación de TV DEBE mostrar la vinculación de la aplicación de entrada de TV cuando se proporciona.

3.12.1.4. Cambio de hora

Las implementaciones de dispositivos Android Television DEBEN admitir el cambio de hora, lo que permite al usuario pausar y reanudar el contenido en vivo. Las implementaciones del dispositivo DEBEN proporcionar al usuario una forma de pausar y reanudar el programa que se está reproduciendo actualmente, si el cambio de hora para ese programa está disponible .

3.12.1.5. grabación de televisión

Las implementaciones de dispositivos Android Television se RECOMIENDAN ENCARECIDAMENTE para admitir la grabación de TV. Si la entrada de TV admite la grabación, la EPG PUEDE proporcionar una forma de grabar un programa si la grabación de dicho programa no está prohibida . Las implementaciones de dispositivos DEBERÍAN proporcionar una interfaz de usuario para reproducir programas grabados.

3.13. Ajustes rápidos

Las implementaciones de dispositivos Android DEBERÍAN incluir un componente de interfaz de usuario de configuración rápida que permita un acceso rápido a las acciones que se utilizan con frecuencia o que se necesitan con urgencia.

Android incluye la API de quicksettings que permite que las aplicaciones de terceros implementen mosaicos que el usuario puede agregar junto con los mosaicos proporcionados por el sistema en el componente de IU de configuración rápida. Si la implementación de un dispositivo tiene un componente de interfaz de usuario de configuración rápida, este:

  • DEBE permitir que el usuario agregue o elimine mosaicos de una aplicación de terceros a la Configuración rápida.
  • NO DEBE agregar automáticamente un mosaico desde una aplicación de terceros directamente a la Configuración rápida.
  • DEBE mostrar todos los mosaicos agregados por el usuario desde aplicaciones de terceros junto con los mosaicos de configuración rápida proporcionados por el sistema.

3.14. API de interfaz de usuario del vehículo

3.14.1. Interfaz de usuario de medios del vehículo

Cualquier implementación de dispositivo que declare soporte automotriz DEBE incluir un marco de interfaz de usuario para admitir aplicaciones de terceros que consumen las API de MediaBrowser y MediaSession .

El marco de la interfaz de usuario que admite aplicaciones de terceros que dependen de MediaBrowser y MediaSession tiene los siguientes requisitos visuales:

  • DEBE mostrar los íconos de MediaItem y los íconos de notificación sin cambios.
  • DEBE mostrar esos elementos como los describe MediaSession, por ejemplo, metadatos, iconos, imágenes.
  • DEBE mostrar el título de la aplicación.
  • DEBE tener un cajón para presentar la jerarquía de MediaBrowser .

4. Compatibilidad de empaquetado de aplicaciones

Las implementaciones de dispositivos DEBEN instalar y ejecutar los archivos ".apk" de Android generados por la herramienta "aapt" incluida en el SDK oficial de Android . Por esta razón, las implementaciones de dispositivos DEBERÍAN utilizar el sistema de gestión de paquetes de la implementación de referencia.

El administrador de paquetes DEBE admitir la verificación de archivos ".apk" mediante el esquema de firma APK v2 y la firma JAR .

Las implementaciones de dispositivos NO DEBEN extender los formatos .apk , Android Manifest , Dalvik bytecode o RenderScript bytecode de tal manera que impida que esos archivos se instalen y ejecuten correctamente en otros dispositivos compatibles.

Las implementaciones de dispositivos NO DEBEN permitir que otras aplicaciones que no sean el "instalador de registro" actual para el paquete desinstalen silenciosamente la aplicación sin ningún aviso, como se documenta en el SDK para el permiso DELETE_PACKAGE . Las únicas excepciones son la aplicación del verificador de paquetes del sistema que maneja la intención PACKAGE_NEEDS_VERIFICATION y la aplicación del administrador de almacenamiento que maneja la intención ACTION_MANAGE_STORAGE .

5. Compatibilidad Multimedia

5.1. Códecs multimedia

Implementaciones de dispositivos:

  • DEBE ser compatible con los formatos de medios principales especificados en la documentación del SDK de Android, excepto donde se permita explícitamente en este documento.

  • DEBE admitir los formatos de medios, codificadores, decodificadores, tipos de archivo y formatos de contenedor definidos en las tablas a continuación y notificados a través de MediaCodecList .

  • También DEBE poder decodificar todos los perfiles informados en su CamcorderProfile

  • DEBE poder decodificar todos los formatos que puede codificar. Esto incluye todos los flujos de bits que generan sus codificadores.

Los códecs DEBERÍAN apuntar a una latencia mínima de códec, en otras palabras, los códecs—

  • NO DEBE consumir y almacenar búferes de entrada y devolver búferes de entrada solo una vez procesados
  • NO DEBE conservar los búferes decodificados durante más tiempo del especificado por el estándar (p. ej., SPS).
  • NO DEBERÍA almacenar búferes codificados por más tiempo del requerido por la estructura GOP.

Todos los códecs enumerados en la siguiente tabla se proporcionan como implementaciones de software en la implementación de Android preferida del Proyecto de código abierto de Android.

Tenga en cuenta que ni Google ni Open Handset Alliance garantizan que estos códecs estén libres de patentes de terceros. Se advierte a quienes tengan la intención de utilizar este código fuente en productos de hardware o software que las implementaciones de este código, incluso en software de código abierto o shareware, pueden requerir licencias de patentes de los titulares de patentes correspondientes.

5.1.1. Códecs de audio

Formato/Códec codificador Descifrador Detalles Tipos de archivo/formatos de contenedor admitidos
Perfil MPEG-4 AAC
(ACA LC)
REQUERIDO 1 REQUERIDO Compatibilidad con contenido mono/estéreo/5.0/5.1 2 con frecuencias de muestreo estándar de 8 a 48 kHz.
  • 3GPP (.3gp)
  • MPEG-4 (.mp4, .m4a)
  • ADTS raw AAC (.aac, decodificación en Android 3.1+, codificación en Android 4.0+, ADIF no compatible)
  • MPEG-TS (.ts, no buscable, Android 3.0+)
Perfil MPEG-4 HE AAC (AAC+) REQUERIDO 1
(Android 4.1+)
REQUERIDO Compatibilidad con contenido mono/estéreo/5.0/5.1 2 con frecuencias de muestreo estándar de 16 a 48 kHz.
MPEG-4 HE AACv2
Perfil (AAC+ mejorado)
REQUERIDO Compatibilidad con contenido mono/estéreo/5.0/5.1 2 con frecuencias de muestreo estándar de 16 a 48 kHz.
AAC ELD (AAC de bajo retardo mejorado) REQUERIDO 1
(Android 4.1+)
REQUERIDO
(Android 4.1+)
Compatibilidad con contenido mono/estéreo con frecuencias de muestreo estándar de 16 a 48 kHz.
AMR-NB REQUERIDO 3 REQUERIDO 3 4,75 a 12,2 kbps muestreados a 8 kHz 3GPP (.3gp)
AMR-BM REQUERIDO 3 REQUERIDO 3 9 tasas de 6,60 kbit/s a 23,85 kbit/s muestreadas a 16 kHz
FLAC REQUERIDO
(Android 3.1+)
Mono/Estéreo (no multicanal). Frecuencias de muestreo de hasta 48 kHz (pero se RECOMIENDA hasta 44,1 kHz en dispositivos con salida de 44,1 kHz, ya que el muestreador descendente de 48 a 44,1 kHz no incluye un filtro de paso bajo). RECOMENDADO 16 bits; no se aplica interpolación para 24 bits. FLAC (.flac) solo
MP3 REQUERIDO Mono/estéreo 8-320 Kbps constante (CBR) o tasa de bits variable (VBR) MP3 (.mp3)
midi REQUERIDO MIDI Tipo 0 y 1. DLS Versión 1 y 2. XMF y Mobile XMF. Compatibilidad con formatos de tono de llamada RTTTL/RTX, OTA e iMelody
  • Escriba 0 y 1 (.mid, .xmf, .mxmf)
  • RTTTL/RTX (.rtttl, .rtx)
  • OTA (.ota)
  • iMelodía (.imy)
Vorbis REQUERIDO
  • Ogg (.ogg)
  • Matroska (.mkv, Android 4.0+)
PCM/ONDA REQUERIDO 4
(Android 4.1+)
REQUERIDO PCM lineal de 16 bits (tasas hasta el límite del hardware). Los dispositivos DEBEN admitir frecuencias de muestreo para grabación PCM sin procesar a frecuencias de 8000, 11025, 16000 y 44100 Hz. ONDA (.wav)
Opus REQUERIDO
(Android 5.0+)
Matroska (.mkv), Ogg (.ogg)

1 Obligatorio para implementaciones de dispositivos que definen android.hardware.microphone pero opcional para implementaciones de dispositivos Android Watch.

2 La grabación o reproducción PUEDE realizarse en mono o estéreo, pero la decodificación de búferes de entrada AAC de transmisiones multicanal (es decir, más de dos canales) a PCM a través del decodificador de audio AAC predeterminado en la API android.media.MediaCodec, DEBE ser lo siguiente: soportado:

  • la decodificación se realiza sin mezcla (por ejemplo, un flujo 5.0 AAC debe decodificarse en cinco canales de PCM, un flujo 5.1 AAC debe decodificarse en seis canales de PCM),
  • metadatos de rango dinámico, como se define en "Control de rango dinámico (DRC)" en ISO/IEC 14496-3, y las claves android.media.MediaFormat DRC para configurar los comportamientos relacionados con el rango dinámico del decodificador de audio. Las claves AAC DRC se introdujeron en la API 21 y son: KEY_AAC_DRC_ATTENUATION_FACTOR, KEY_AAC_DRC_BOOST_FACTOR, KEY_AAC_DRC_HEAVY_COMPRESSION, KEY_AAC_DRC_TARGET_REFERENCE_LEVEL y KEY_AAC_ENCODED_TARGET_LEVEL

3 Requerido para implementaciones de dispositivos portátiles Android.

4 Obligatorio para las implementaciones de dispositivos que definen android.hardware.microphone, incluidas las implementaciones de dispositivos Android Watch.

5.1.2. Códecs de imagen

Formato/Códec codificador Descifrador Detalles Tipos de archivo/formatos de contenedor admitidos
jpeg REQUERIDO REQUERIDO Base+progresivo JPEG (.jpg)
GIF REQUERIDO GIF (.gif)
PNG REQUERIDO REQUERIDO PNG (.png)
BMP REQUERIDO BMP (.bmp)
WebP REQUERIDO REQUERIDO WebP (.webp)
Crudo REQUERIDO ARW (.arw), CR2 (.cr2), DNG (.dng), NEF (.nef), NRW (.nrw), ORF (.orf), PEF (.pef), RAF (.raf), RW2 ( .rw2), SRW (.srw)

5.1.3. Códecs de vídeo

  • Los códecs que anuncian la compatibilidad con el perfil HDR DEBEN admitir el análisis y la gestión de metadatos estáticos HDR.

  • Si un códec de medios anuncia soporte de actualización interna, DEBE admitir los períodos de actualización en el rango de 10 a 60 cuadros y operar con precisión dentro del 20% del período de actualización configurado.

  • Los códecs de video DEBEN admitir tamaños de bytebuffer de salida y entrada que acomoden el marco comprimido y sin comprimir más grande posible según lo dictado por el estándar y la configuración, pero sin sobreasignar.

  • Los codificadores y decodificadores de video DEBEN admitir el formato de color flexible YUV420 (COLOR_FormatYUV420Flexible).

Formato/Códec codificador Descifrador Detalles Tipos de archivos compatibles/
Formatos de contenedores
H.263 MAYO MAYO
  • 3GPP (.3gp)
  • MPEG-4 (.mp4)
H.264 AVC REQUERIDO 2 REQUERIDO 2 Consulte las secciones 5.2 y 5.3 para obtener más información.
  • 3GPP (.3gp)
  • MPEG-4 (.mp4)
  • MPEG-2 TS (.ts, solo audio AAC, no se puede buscar, Android 3.0+)
H.265 HEVC REQUERIDO 5 Consulte la sección 5.3 para obtener más información. MPEG-4 (.mp4)
MPEG-2 MUY RECOMENDADO 6 Perfil principal MPEG2-TS
MPEG-4SP REQUERIDO 2 3GPP (.3gp)
VP8 3 REQUERIDO 2
(Android 4.3+)
REQUERIDO 2
(Android 2.3.3+)
Consulte las secciones 5.2 y 5.3 para obtener más información.
VP9 REQUERIDO 2
(Android 4.4+)
Consulte la sección 5.3 para obtener más información.

1 Requerido para implementaciones de dispositivos que incluyen hardware de cámara y definen android.hardware.camera o android.hardware.camera.front.

2 Requerido para implementaciones de dispositivos, excepto dispositivos Android Watch.

3 Para una calidad aceptable de los servicios de transmisión de video web y videoconferencia, las implementaciones de dispositivos DEBERÍAN usar un códec de hardware VP8 que cumpla con los requisitos .

4 Las implementaciones de dispositivos DEBERÍAN admitir la escritura de archivos Matroska WebM.

5 MUY RECOMENDADO para Android Automotive, opcional para Android Watch y obligatorio para todos los demás tipos de dispositivos.

6 Solo se aplica a las implementaciones de dispositivos Android Television.

5.2. Codificación de vídeo

Los códecs de video son opcionales para las implementaciones de dispositivos Android Watch.

Codificadores de video H.264, VP8, VP9 y HEVC—

  • DEBE admitir tasas de bits configurables dinámicamente.
  • DEBERÍA admitir velocidades de cuadro variables, donde el codificador de video DEBERÍA determinar la duración instantánea del cuadro en función de las marcas de tiempo de los búferes de entrada y asignar su contenedor de bits en función de esa duración del cuadro.

El codificador de video H.263 y MPEG-4 DEBERÍA admitir tasas de bits configurables dinámicamente.

Todos los codificadores de video DEBERÍAN cumplir con los siguientes objetivos de tasa de bits en dos ventanas deslizantes:

  • No DEBE ser más del ~15 % por encima de la tasa de bits entre los intervalos intraframe (I-frame).
  • No DEBE ser más del ~100 % por encima de la tasa de bits en una ventana deslizante de 1 segundo.

5.2.1. H.263

Las implementaciones de dispositivos Android con codificadores H.263 DEBEN ser compatibles con el nivel de perfil de referencia 45.

5.2.2. H-264

Implementaciones de dispositivos Android compatibles con el códec H.264:

  • DEBE ser compatible con el perfil de referencia de nivel 3.
    Sin embargo, el soporte para ASO (Orden arbitrario de segmentos), FMO (Orden flexible de macrobloques) y RS (Rebanadas redundantes) es OPCIONAL. Además, para mantener la compatibilidad con otros dispositivos Android, se RECOMIENDA que los codificadores no utilicen ASO, FMO y RS para el perfil de referencia.
  • DEBE admitir los perfiles de codificación de video SD (definición estándar) en la siguiente tabla.
  • DEBE ser compatible con el perfil principal de nivel 4.
  • DEBERÍA admitir los perfiles de codificación de video HD (alta definición) como se indica en la siguiente tabla.
  • Además, se RECOMIENDA ENCARECIDAMENTE que los dispositivos Android Television codifiquen video HD 1080p a 30 fps.
SD (Baja calidad) SD (alta calidad) HD 720p 1 Alta definición 1080p 1
Resolución de video 320 x 240 píxeles 720 x 480 píxeles 1280 x 720 píxeles 1920 x 1080 píxeles
Velocidad de fotogramas de vídeo 20fps 30fps 30fps 30fps
Bitrate de vídeo 384 kbps 2Mbps 4Mbps 10Mbps

1 Cuando sea compatible con el hardware, pero MUY RECOMENDADO para dispositivos Android Television.

5.2.3. VP8

Las implementaciones de dispositivos Android compatibles con el códec VP8 DEBEN admitir los perfiles de codificación de video SD y DEBERÍAN admitir los siguientes perfiles de codificación de video HD (alta definición).

SD (Baja calidad) SD (alta calidad) HD 720p 1 Alta definición 1080p 1
Resolución de video 320 x 180 píxeles 640 x 360 píxeles 1280 x 720 píxeles 1920 x 1080 píxeles
Velocidad de fotogramas de vídeo 30fps 30fps 30fps 30fps
Bitrate de vídeo 800 kbps 2Mbps 4Mbps 10Mbps

1 Cuando es compatible con el hardware.

5.3. Decodificación de vídeo

Los códecs de video son opcionales para las implementaciones de dispositivos Android Watch.

Implementaciones de dispositivos—

  • DEBE ser compatible con la resolución de video dinámica y el cambio de velocidad de fotogramas a través de las API estándar de Android dentro de la misma transmisión para todos los códecs VP8, VP9, ​​H.264 y H.265 en tiempo real y hasta la resolución máxima admitida por cada códec en el dispositivo.

  • Implementaciones compatibles con el decodificador Dolby Vision:

  • DEBE proporcionar un extractor compatible con Dolby Vision.
  • DEBE mostrar correctamente el contenido de Dolby Vision en la pantalla del dispositivo o en un puerto de salida de video estándar (p. ej., HDMI).

  • Las implementaciones que proporcionan un extractor compatible con Dolby Vision DEBEN configurar el índice de pista de las capas base compatibles con versiones anteriores (si las hay) para que sea el mismo que el índice de pista de la capa Dolby Vision combinada.

5.3.1. MPEG-2

Las implementaciones de dispositivos Android con decodificadores MPEG-2 deben ser compatibles con el perfil principal de alto nivel.

5.3.2. H.263

Las implementaciones de dispositivos Android con decodificadores H.263 DEBEN ser compatibles con los niveles 30 y 45 del perfil básico.

5.3.3. MPEG-4

Las implementaciones de dispositivos Android con decodificadores MPEG-4 DEBEN ser compatibles con el perfil simple de nivel 3.

5.3.4. H.264

Implementaciones de dispositivos Android con decodificadores H.264:

  • DEBE ser compatible con el perfil principal de nivel 3.1 y el perfil básico.
    El soporte para ASO (Orden arbitraria de segmentos), FMO (Orden flexible de macrobloques) y RS (Rebanadas redundantes) es OPCIONAL.
  • DEBE ser capaz de decodificar videos con los perfiles SD (definición estándar) enumerados en la siguiente tabla y codificados con el perfil básico y el perfil principal de nivel 3.1 (incluido 720p30).
  • DEBE ser capaz de decodificar videos con los perfiles HD (alta definición) como se indica en la siguiente tabla.
  • Además, los dispositivos Android Television:
    • DEBE admitir High Profile Level 4.2 y el perfil de decodificación HD 1080p60.
    • DEBE ser capaz de decodificar videos con ambos perfiles HD como se indica en la siguiente tabla y codificados con el perfil básico, el perfil principal o el perfil alto Nivel 4.2
SD (Baja calidad) SD (alta calidad) HD 720p 1 Alta definición 1080p 1
Resolución de video 320 x 240 píxeles 720 x 480 píxeles 1280 x 720 píxeles 1920 x 1080 píxeles
Velocidad de fotogramas de vídeo 30fps 30fps 60 fps 30 fps (60 fps 2 )
Bitrate de vídeo 800 kbps 2Mbps 8Mbps 20Mbps

1 REQUERIDO para cuando la altura informada por el método Display.getSupportedModes() es igual o mayor que la resolución del video.

2 OBLIGATORIOS para implementaciones de dispositivos Android Television.

5.3.5. H.265 (HEVC)

Implementaciones de dispositivos Android, cuando se admite el códec H.265 como se describe en la sección 5.1.3 :

  • MUST support the Main Profile Level 3 Main tier and the SD video decoding profiles as indicated in the following table.
  • SHOULD support the HD decoding profiles as indicated in the following table.
  • MUST support the HD decoding profiles as indicated in the following table if there is a hardware decoder.
  • In addition, Android Television devices:
  • MUST support the HD 720p decoding profile.
  • STRONGLY RECOMMENDED to support the HD 1080p decoding profile. If the HD 1080p decoding profile is supported, it MUST support the Main Profile Level 4.1 Main tier.
  • SHOULD support the UHD decoding profile. If the UHD decoding profile is supported the codec MUST support Main10 Level 5 Main Tier profile.
SD (Low quality) SD (High quality) HD 720p HD 1080p UHD
Video resolution 352 x 288 px 720 x 480 px 1280 x 720 px 1920 x 1080 px 3840 x 2160 px
Video frame rate 30 fps 30 fps 30 fps 30 fps (60 fps 1 ) 60 fps
Video bitrate 600 Kbps 1.6 Mbps 4 Mbps 5 Mbps 20 Mbps

1 REQUIRED for Android Television device implementations with H.265 hardware decoding.

5.3.6. VP8

Android device implementations, when supporting VP8 codec as described in section 5.1.3 :

  • MUST support the SD decoding profiles in the following table.
  • SHOULD support the HD decoding profiles in the following table.
  • Android Television devices MUST support the HD 1080p60 decoding profile.
SD (Low quality) SD (High quality) HD 720p 1 HD 1080p 1
Video resolution 320 x 180 px 640 x 360 px 1280 x 720 px 1920 x 1080 px
Video frame rate 30 fps 30 fps 30 fps (60 fps 2 ) 30 (60 fps 2 )
Video bitrate 800 Kbps 2 Mbps 8 Mbps 20 Mbps

1 REQUIRED for when the height as reported by the Display.getSupportedModes() method is equal or greater than the video resolution.

2 REQUIRED for Android Television device implementations.

5.3.7. VP9

Android device implementations, when supporting VP9 codec as described in section 5.1.3 :

  • MUST support the SD video decoding profiles as indicated in the following table.
  • SHOULD support the HD decoding profiles as indicated in the following table.
  • MUST support the HD decoding profiles as indicated in the following table, if there is a hardware decoder.
  • In addition, Android Television devices:

    • MUST support the HD 720p decoding profile.
    • STRONGLY RECOMMENDED to support the HD 1080p decoding profile.
    • SHOULD support the UHD decoding profile. If the UHD video decoding profile is supported, it MUST support 8-bit color depth and SHOULD support VP9 Profile 2 (10-bit).
SD (Low quality) SD (High quality) HD 720p HD 1080p UHD
Video resolution 320 x 180 px 640 x 360 px 1280 x 720 px 1920 x 1080 px 3840 x 2160 px
Video frame rate 30 fps 30 fps 30 fps 30 fps (60 fps 1 ) 60 fps
Video bitrate 600 Kbps 1.6 Mbps 4 Mbps 5 Mbps 20 Mbps

1 REQUIRED for Android Television device implementations with VP9 hardware decoding.

5.4. Audio Recording

While some of the requirements outlined in this section are stated as SHOULD since Android 4.3, the Compatibility Definition for a future version is planned to change these to MUST. Existing and new Android devices are STRONGLY RECOMMENDED to meet these requirements that are stated as SHOULD, or they will not be able to attain Android compatibility when upgraded to the future version.

5.4.1. Raw Audio Capture

Device implementations that declare android.hardware.microphone MUST allow capture of raw audio content with the following characteristics:

  • Format : Linear PCM, 16-bit
  • Sampling rates : 8000, 11025, 16000, 44100
  • Channels : Mono

The capture for the above sample rates MUST be done without up-sampling, and any down-sampling MUST include an appropriate anti-aliasing filter.

Device implementations that declare android.hardware.microphone SHOULD allow capture of raw audio content with the following characteristics:

  • Format : Linear PCM, 16-bit
  • Sampling rates : 22050, 48000
  • Channels : Stereo

If capture for the above sample rates is supported, then the capture MUST be done without up-sampling at any ratio higher than 16000:22050 or 44100:48000. Any up-sampling or down-sampling MUST include an appropriate anti-aliasing filter.

5.4.2. Capture for Voice Recognition

The android.media.MediaRecorder.AudioSource.VOICE_RECOGNITION audio source MUST support capture at one of the sampling rates, 44100 and 48000.

In addition to the above recording specifications, when an application has started recording an audio stream using the android.media.MediaRecorder.AudioSource.VOICE_RECOGNITION audio source:

  • The device SHOULD exhibit approximately flat amplitude versus frequency characteristics: specifically, ±3 dB, from 100 Hz to 4000 Hz.
  • Audio input sensitivity SHOULD be set such that a 90 dB sound power level (SPL) source at 1000 Hz yields RMS of 2500 for 16-bit samples.
  • PCM amplitude levels SHOULD linearly track input SPL changes over at least a 30 dB range from -18 dB to +12 dB re 90 dB SPL at the microphone.
  • Total harmonic distortion SHOULD be less than 1% for 1 kHz at 90 dB SPL input level at the microphone.
  • Noise reduction processing, if present, MUST be disabled.
  • Automatic gain control, if present, MUST be disabled.

If the platform supports noise suppression technologies tuned for speech recognition, the effect MUST be controllable from the android.media.audiofx.NoiseSuppressor API. Moreover, the UUID field for the noise suppressor's effect descriptor MUST uniquely identify each implementation of the noise suppression technology.

5.4.3. Capture for Rerouting of Playback

The android.media.MediaRecorder.AudioSource class includes the REMOTE_SUBMIX audio source. Devices that declare android.hardware.audio.output MUST properly implement the REMOTE_SUBMIX audio source so that when an application uses the android.media.AudioRecord API to record from this audio source, it can capture a mix of all audio streams except for the following:

  • STREAM_RING
  • STREAM_ALARM
  • STREAM_NOTIFICATION

5.5. Audio Playback

Device implementations that declare android.hardware.audio.output MUST conform to the requirements in this section.

5.5.1. Raw Audio Playback

The device MUST allow playback of raw audio content with the following characteristics:

  • Format : Linear PCM, 16-bit
  • Sampling rates : 8000, 11025, 16000, 22050, 32000, 44100
  • Channels : Mono, Stereo

The device SHOULD allow playback of raw audio content with the following characteristics:

  • Sampling rates : 24000, 48000

5.5.2. Audio Effects

Android provides an API for audio effects for device implementations. Device implementations that declare the feature android.hardware.audio.output:

  • MUST support the EFFECT_TYPE_EQUALIZER and EFFECT_TYPE_LOUDNESS_ENHANCER implementations controllable through the AudioEffect subclasses Equalizer, LoudnessEnhancer.
  • MUST support the visualizer API implementation, controllable through the Visualizer class.
  • SHOULD support the EFFECT_TYPE_BASS_BOOST, EFFECT_TYPE_ENV_REVERB, EFFECT_TYPE_PRESET_REVERB, and EFFECT_TYPE_VIRTUALIZER implementations controllable through the AudioEffect sub-classes BassBoost, EnvironmentalReverb, PresetReverb, and Virtualizer.

5.5.3. Audio Output Volume

Android Television device implementations MUST include support for system Master Volume and digital audio output volume attenuation on supported outputs, except for compressed audio passthrough output (where no audio decoding is done on the device).

Android Automotive device implementations SHOULD allow adjusting audio volume separately per each audio stream using the content type or usage as defined by AudioAttributes and car audio usage as publicly defined in android.car.CarAudioManager .

5.6. Audio Latency

Audio latency is the time delay as an audio signal passes through a system. Many classes of applications rely on short latencies, to achieve real-time sound effects.

For the purposes of this section, use the following definitions:

  • output latency . The interval between when an application writes a frame of PCM-coded data and when the corresponding sound is presented to environment at an on-device transducer or signal leaves the device via a port and can be observed externally.
  • cold output latency . The output latency for the first frame, when the audio output system has been idle and powered down prior to the request.
  • continuous output latency . The output latency for subsequent frames, after the device is playing audio.
  • input latency . The interval between when a sound is presented by environment to device at an on-device transducer or signal enters the device via a port and when an application reads the corresponding frame of PCM-coded data.
  • lost input . The initial portion of an input signal that is unusable or unavailable.
  • cold input latency . The sum of lost input time and the input latency for the first frame, when the audio input system has been idle and powered down prior to the request.
  • continuous input latency . The input latency for subsequent frames, while the device is capturing audio.
  • cold output jitter . The variability among separate measurements of cold output latency values.
  • cold input jitter . The variability among separate measurements of cold input latency values.
  • continuous round-trip latency . The sum of continuous input latency plus continuous output latency plus one buffer period. The buffer period allows time for the app to process the signal and time for the app to mitigate phase difference between input and output streams.
  • OpenSL ES PCM buffer queue API . The set of PCM-related OpenSL ES APIs within Android NDK .

Device implementations that declare android.hardware.audio.output are STRONGLY RECOMMENDED to meet or exceed these audio output requirements:

  • cold output latency of 100 milliseconds or less
  • continuous output latency of 45 milliseconds or less
  • minimize the cold output jitter

If a device implementation meets the requirements of this section after any initial calibration when using the OpenSL ES PCM buffer queue API, for continuous output latency and cold output latency over at least one supported audio output device, it is STRONGLY RECOMMENDED to report support for low-latency audio, by reporting the feature android.hardware.audio.low_latency via the android.content.pm.PackageManager class. Conversely, if the device implementation does not meet these requirements it MUST NOT report support for low-latency audio.

Device implementations that include android.hardware.microphone are STRONGLY RECOMMENDED to meet these input audio requirements:

  • cold input latency of 100 milliseconds or less
  • continuous input latency of 30 milliseconds or less
  • continuous round-trip latency of 50 milliseconds or less
  • minimize the cold input jitter

5.7. Network Protocols

Devices MUST support the media network protocols for audio and video playback as specified in the Android SDK documentation. Specifically, devices MUST support the following media network protocols:

Segment formats Reference(s) Required codec support
MPEG-2 Transport Stream ISO 13818 Video codecs:
  • H264 AVC
  • MPEG-4 SP
  • MPEG-2
See section 5.1.3 for details on H264 AVC, MPEG2-4 SP,
and MPEG-2.

Audio codecs:

  • AAC
See section 5.1.1 for details on AAC and its variants.
AAC with ADTS framing and ID3 tags ISO 13818-7 See section 5.1.1 for details on AAC and its variants
WebVTT WebVTT
  • RTSP (RTP, SDP)

    The following RTP audio video profile and related codecs MUST be supported. For exceptions please see the table footnotes in section 5.1 .

Profile name Reference(s) Required codec support
H264 AVC RFC 6184 See section 5.1.3 for details on H264 AVC
MP4A-LATM RFC 6416 See section 5.1.1 for details on AAC and its variants
H263-1998 RFC 3551
RFC 4629
RFC 2190
See section 5.1.3 for details on H263
H263-2000 RFC 4629 See section 5.1.3 for details on H263
AMR RFC 4867 See section 5.1.1 for details on AMR-NB
AMR-WB RFC 4867 See section 5.1.1 for details on AMR-WB
MP4V-ES RFC 6416 See section 5.1.3 for details on MPEG-4 SP
mpeg4-generic RFC 3640 See section 5.1.1 for details on AAC and its variants
MP2T RFC 2250 See MPEG-2 Transport Stream underneath HTTP Live Streaming for details

5.8. Secure Media

Device implementations that support secure video output and are capable of supporting secure surfaces MUST declare support for Display.FLAG_SECURE. Device implementations that declare support for Display.FLAG_SECURE, if they support a wireless display protocol, MUST secure the link with a cryptographically strong mechanism such as HDCP 2.x or higher for Miracast wireless displays. Similarly if they support a wired external display, the device implementations MUST support HDCP 1.2 or higher. Android Television device implementations MUST support HDCP 2.2 for devices supporting 4K resolution and HDCP 1.4 or above for lower resolutions. The upstream Android open source implementation includes support for wireless (Miracast) and wired (HDMI) displays that satisfies this requirement.

5.9. Musical Instrument Digital Interface (MIDI)

If a device implementation supports the inter-app MIDI software transport (virtual MIDI devices), and it supports MIDI over all of the following MIDI-capable hardware transports for which it provides generic non-MIDI connectivity, it is STRONGLY RECOMMENDED to report support for feature android.software.midi via the android.content.pm.PackageManager class.

The MIDI-capable hardware transports are:

  • USB host mode (section 7.7 USB)
  • USB peripheral mode (section 7.7 USB)
  • MIDI over Bluetooth LE acting in central role (section 7.4.3 Bluetooth)

Conversely, if the device implementation provides generic non-MIDI connectivity over a particular MIDI-capable hardware transport listed above, but does not support MIDI over that hardware transport, it MUST NOT report support for feature android.software.midi.

5.10. Professional Audio

If a device implementation meets all of the following requirements, it is STRONGLY RECOMMENDED to report support for feature android.hardware.audio.pro via the android.content.pm.PackageManager class.

  • The device implementation MUST report support for feature android.hardware.audio.low_latency.
  • The continuous round-trip audio latency, as defined in section 5.6 Audio Latency, MUST be 20 milliseconds or less and SHOULD be 10 milliseconds or less over at least one supported path.
  • If the device includes a 4 conductor 3.5mm audio jack, the continuous round-trip audio latency MUST be 20 milliseconds or less over the audio jack path, and SHOULD be 10 milliseconds or less over at the audio jack path.
  • The device implementation MUST include a USB port(s) supporting USB host mode and USB peripheral mode.
  • The USB host mode MUST implement the USB audio class.
  • If the device includes an HDMI port, the device implementation MUST support output in stereo and eight channels at 20-bit or 24-bit depth and 192 kHz without bit-depth loss or resampling.
  • The device implementation MUST report support for feature android.software.midi.
  • If the device includes a 4 conductor 3.5mm audio jack, the device implementation is STRONGLY RECOMMENDED to comply with section Mobile device (jack) specifications of the Wired Audio Headset Specification (v1.1) .

Latencies and USB audio requirements MUST be met using the OpenSL ES PCM buffer queue API.

In addition, a device implementation that reports support for this feature SHOULD:

  • Provide a sustainable level of CPU performance while audio is active.
  • Minimize audio clock inaccuracy and drift relative to standard time.
  • Minimize audio clock drift relative to the CPU CLOCK_MONOTONIC when both are active.
  • Minimize audio latency over on-device transducers.
  • Minimize audio latency over USB digital audio.
  • Document audio latency measurements over all paths.
  • Minimize jitter in audio buffer completion callback entry times, as this affects usable percentage of full CPU bandwidth by the callback.
  • Provide zero audio underruns (output) or overruns (input) under normal use at reported latency.
  • Provide zero inter-channel latency difference.
  • Minimize MIDI mean latency over all transports.
  • Minimize MIDI latency variability under load (jitter) over all transports.
  • Provide accurate MIDI timestamps over all transports.
  • Minimize audio signal noise over on-device transducers, including the period immediately after cold start.
  • Provide zero audio clock difference between the input and output sides of corresponding end-points, when both are active. Examples of corresponding end-points include the on-device microphone and speaker, or the audio jack input and output.
  • Handle audio buffer completion callbacks for the input and output sides of corresponding end-points on the same thread when both are active, and enter the output callback immediately after the return from the input callback. Or if it is not feasible to handle the callbacks on the same thread, then enter the output callback shortly after entering the input callback to permit the application to have a consistent timing of the input and output sides.
  • Minimize the phase difference between HAL audio buffering for the input and output sides of corresponding end-points.
  • Minimize touch latency.
  • Minimize touch latency variability under load (jitter).

5.11. Capture for Unprocessed

Starting from Android 7.0, a new recording source has been added. It can be accessed using the android.media.MediaRecorder.AudioSource.UNPROCESSED audio source. In OpenSL ES, it can be accessed with the record preset SL_ANDROID_RECORDING_PRESET_UNPROCESSED .

A device MUST satisfy all of the following requirements to report support of the unprocessed audio source via the android.media.AudioManager property PROPERTY_SUPPORT_AUDIO_SOURCE_UNPROCESSED :

  • The device MUST exhibit approximately flat amplitude-versus-frequency characteristics in the mid-frequency range: specifically ±10dB from 100 Hz to 7000 Hz.

  • The device MUST exhibit amplitude levels in the low frequency range: specifically from ±20 dB from 5 Hz to 100 Hz compared to the mid-frequency range.

  • The device MUST exhibit amplitude levels in the high frequency range: specifically from ±30 dB from 7000 Hz to 22 KHz compared to the mid-frequency range.

  • Audio input sensitivity MUST be set such that a 1000 Hz sinusoidal tone source played at 94 dB Sound Pressure Level (SPL) yields a response with RMS of 520 for 16 bit-samples (or -36 dB Full Scale for floating point/double precision samples).

  • SNR > 60 dB (difference between 94 dB SPL and equivalent SPL of self noise, A-weighted).

  • Total harmonic distortion MUST be less than 1% for 1 kHZ at 90 dB SPL input level at the microphone.

  • The only signal processing allowed in the path is a level multiplier to bring the level to desired range. This level multiplier MUST NOT introduce delay or latency to the signal path.

  • No other signal processing is allowed in the path, such as Automatic Gain Control, High Pass Filter, or Echo Cancellation. If any signal processing is present in the architecture for any reason, it MUST be disabled and effectively introduce zero delay or extra latency to the signal path.

All SPL measurements are made directly next to the microphone under test.

For multiple microphone configurations, these requirements apply to each microphone.

It is STRONGLY RECOMMENDED that a device satisfy as many of the requirements for the signal path for the unprocessed recording source; however, a device must satisfy all of these requirements, listed above, if it claims to support the unprocessed audio source.

6. Developer Tools and Options Compatibility

6.1. Developer Tools

Device implementations MUST support the Android Developer Tools provided in the Android SDK. Android compatible devices MUST be compatible with:

  • Android Debug Bridge (adb)
    • Device implementations MUST support all adb functions as documented in the Android SDK including dumpsys .
    • The device-side adb daemon MUST be inactive by default and there MUST be a user-accessible mechanism to turn on the Android Debug Bridge. If a device implementation omits USB peripheral mode, it MUST implement the Android Debug Bridge via local-area network (such as Ethernet or 802.11).
    • Android includes support for secure adb. Secure adb enables adb on known authenticated hosts. Device implementations MUST support secure adb.
  • Dalvik Debug Monitor Service (ddms)
    • Device implementations MUST support all ddms features as documented in the Android SDK.
    • As ddms uses adb, support for ddms SHOULD be inactive by default, but MUST be supported whenever the user has activated the Android Debug Bridge, as above.
  • Monkey Device implementations MUST include the Monkey framework, and make it available for applications to use.
  • SysTrace
    • Device implementations MUST support systrace tool as documented in the Android SDK. Systrace must be inactive by default, and there MUST be a user-accessible mechanism to turn on Systrace.
    • Most Linux-based systems and Apple Macintosh systems recognize Android devices using the standard Android SDK tools, without additional support; however Microsoft Windows systems typically require a driver for new Android devices. (For instance, new vendor IDs and sometimes new device IDs require custom USB drivers for Windows systems.)
    • If a device implementation is unrecognized by the adb tool as provided in the standard Android SDK, device implementers MUST provide Windows drivers allowing developers to connect to the device using the adb protocol. These drivers MUST be provided for Windows XP, Windows Vista, Windows 7, Windows 8, and Windows 10 in both 32-bit and 64-bit versions.

6.2. Developer Options

Android includes support for developers to configure application development-related settings. Device implementations MUST honor the android.settings.APPLICATION_DEVELOPMENT_SETTINGS intent to show application development-related settings The upstream Android implementation hides the Developer Options menu by default and enables users to launch Developer Options after pressing seven (7) times on the Settings > About Device > Build Number menu item. Device implementations MUST provide a consistent experience for Developer Options. Specifically, device implementations MUST hide Developer Options by default and MUST provide a mechanism to enable Developer Options that is consistent with the upstream Android implementation.

Android Automotive implementations MAY limit access to the Developer Options menu by visually hiding or disabling the menu when the vehicle is in motion.

7. Hardware Compatibility

If a device includes a particular hardware component that has a corresponding API for third-party developers, the device implementation MUST implement that API as described in the Android SDK documentation. If an API in the SDK interacts with a hardware component that is stated to be optional and the device implementation does not possess that component:

  • Complete class definitions (as documented by the SDK) for the component APIs MUST still be presented.
  • The API's behaviors MUST be implemented as no-ops in some reasonable fashion.
  • API methods MUST return null values where permitted by the SDK documentation.
  • API methods MUST return no-op implementations of classes where null values are not permitted by the SDK documentation.
  • API methods MUST NOT throw exceptions not documented by the SDK documentation.

A typical example of a scenario where these requirements apply is the telephony API: Even on non-phone devices, these APIs must be implemented as reasonable no-ops.

Device implementations MUST consistently report accurate hardware configuration information via the getSystemAvailableFeatures() and hasSystemFeature(String) methods on the android.content.pm.PackageManager class for the same build fingerprint.

7.1. Display and Graphics

Android includes facilities that automatically adjust application assets and UI layouts appropriately for the device to ensure that third-party applications run well on a variety of hardware configurations . Devices MUST properly implement these APIs and behaviors, as detailed in this section.

The units referenced by the requirements in this section are defined as follows:

  • physical diagonal size . The distance in inches between two opposing corners of the illuminated portion of the display.
  • dots per inch (dpi) . The number of pixels encompassed by a linear horizontal or vertical span of 1”. Where dpi values are listed, both horizontal and vertical dpi must fall within the range.
  • aspect ratio . The ratio of the pixels of the longer dimension to the shorter dimension of the screen. For example, a display of 480x854 pixels would be 854/480 = 1.779, or roughly “16:9”.
  • density-independent pixel (dp) . The virtual pixel unit normalized to a 160 dpi screen, calculated as: pixels = dps * (density/160).

7.1.1. Screen Configuration

7.1.1.1. Screen Size

Android Watch devices (detailed in section 2 ) MAY have smaller screen sizes as described in this section.

The Android UI framework supports a variety of different screen sizes, and allows applications to query the device screen size (aka “screen layout") via android.content.res.Configuration.screenLayout with the SCREENLAYOUT_SIZE_MASK. Device implementations MUST report the correct screen size as defined in the Android SDK documentation and determined by the upstream Android platform. Specifically, device implementations MUST report the correct screen size according to the following logical density-independent pixel (dp) screen dimensions.

  • Devices MUST have screen sizes of at least 426 dp x 320 dp ('small'), unless it is an Android Watch device.
  • Devices that report screen size 'normal' MUST have screen sizes of at least 480 dp x 320 dp.
  • Devices that report screen size 'large' MUST have screen sizes of at least 640 dp x 480 dp.
  • Devices that report screen size 'xlarge' MUST have screen sizes of at least 960 dp x 720 dp.

In addition:

  • Android Watch devices MUST have a screen with the physical diagonal size in the range from 1.1 to 2.5 inches.
  • Android Automotive devices MUST have a screen with the physical diagonal size greater than or equal to 6 inches.
  • Android Automotive devices MUST have a screen size of at least 750 dp x 480 dp.
  • Other types of Android device implementations, with a physically integrated screen, MUST have a screen at least 2.5 inches in physical diagonal size.

Devices MUST NOT change their reported screen size at any time.

Applications optionally indicate which screen sizes they support via the <supports-screens> attribute in the AndroidManifest.xml file. Device implementations MUST correctly honor applications' stated support for small, normal, large, and xlarge screens, as described in the Android SDK documentation.

7.1.1.2. Screen Aspect Ratio

While there is no restriction to the screen aspect ratio value of the physical screen display, the screen aspect ratio of the surface that third-party apps are rendered on and which can be derived from the values reported via the DisplayMetrics MUST meet the following requirements:

  • If the uiMode is configured as UI_MODE_TYPE_WATCH, the aspect ratio value MAY be set as 1.0 (1:1).
  • If the third-party app indicates that it is resizeable via the android:resizeableActivity attribute, there are no restrictions to the aspect ratio value.
  • For all other cases, the aspect ratio MUST be a value between 1.3333 (4:3) and 1.86 (roughly 16:9) unless the app has indicated explicitly that it supports a higher screen aspect ratio through the maxAspectRatio metadata value.

7.1.1.3. Densidad de pantalla

The Android UI framework defines a set of standard logical densities to help application developers target application resources. By default, device implementations MUST report only one of the following logical Android framework densities through the DENSITY_DEVICE_STABLE API and this value MUST NOT change at any time; however, the device MAY report a different arbitrary density according to the display configuration changes made by the user (for example, display size) set after initial boot.

  • 120 ppp (ldpi)
  • 160 ppp (mdpi)
  • 213 ppp (tvdpi)
  • 240 ppp (hdpi)
  • 260 dpi (260dpi)
  • 280 ppp (280 ppp)
  • 300 dpi (300dpi)
  • 320 ppp (xhdpi)
  • 340 dpi (340dpi)
  • 360 ppp (360 ppp)
  • 400 ppp (400 ppp)
  • 420 ppp (420 ppp)
  • 480 ppp (xxhdpi)
  • 560 ppp (560 ppp)
  • 640 ppp (xxx hdpi)

Device implementations SHOULD define the standard Android framework density that is numerically closest to the physical density of the screen, unless that logical density pushes the reported screen size below the minimum supported. If the standard Android framework density that is numerically closest to the physical density results in a screen size that is smaller than the smallest supported compatible screen size (320 dp width), device implementations SHOULD report the next lowest standard Android framework density.

Device implementations are STRONGLY RECOMMENDED to provide users a setting to change the display size. If there is an implementation to change the display size of the device, it MUST align with the AOSP implementation as indicated below:

  • The display size MUST NOT be scaled any larger than 1.5 times the native density or produce an effective minimum screen dimension smaller than 320dp (equivalent to resource qualifier sw320dp), whichever comes first.
  • Display size MUST NOT be scaled any smaller than 0.85 times the native density.
  • To ensure good usability and consistent font sizes, it is RECOMMENDED that the following scaling of Native Display options be provided (while complying with the limits specified above)
  • Small: 0.85x
  • Default: 1x (Native display scale)
  • Large: 1.15x
  • Larger: 1.3x
  • Largest 1.45x

7.1.2. Display Metrics

Device implementations MUST report correct values for all display metrics defined in android.util.DisplayMetrics and MUST report the same values regardless of whether the embedded or external screen is used as the default display.

7.1.3. Screen Orientation

Devices MUST report which screen orientations they support (android.hardware.screen.portrait and/or android.hardware.screen.landscape) and MUST report at least one supported orientation. For example, a device with a fixed orientation landscape screen, such as a television or laptop, SHOULD only report android.hardware.screen.landscape.

Devices that report both screen orientations MUST support dynamic orientation by applications to either portrait or landscape screen orientation. That is, the device must respect the application's request for a specific screen orientation. Device implementations MAY select either portrait or landscape orientation as the default.

Devices MUST report the correct value for the device's current orientation, whenever queried via the android.content.res.Configuration.orientation, android.view.Display.getOrientation(), or other APIs.

Devices MUST NOT change the reported screen size or density when changing orientation.

7.1.4. 2D and 3D Graphics Acceleration

Device implementations MUST support both OpenGL ES 1.0 and 2.0, as embodied and detailed in the Android SDK documentations. Device implementations SHOULD support OpenGL ES 3.0, 3.1, or 3.2 on devices capable of supporting it. Device implementations MUST also support Android RenderScript , as detailed in the Android SDK documentation.

Device implementations MUST also correctly identify themselves as supporting OpenGL ES 1.0, OpenGL ES 2.0, OpenGL ES 3.0, OpenGL 3.1, or OpenGL 3.2. That is:

  • The managed APIs (such as via the GLES10.getString() method) MUST report support for OpenGL ES 1.0 and OpenGL ES 2.0.
  • The native C/C++ OpenGL APIs (APIs available to apps via libGLES_v1CM.so, libGLES_v2.so, or libEGL.so) MUST report support for OpenGL ES 1.0 and OpenGL ES 2.0.
  • Device implementations that declare support for OpenGL ES 3.0, 3.1, or 3.2 MUST support the corresponding managed APIs and include support for native C/C++ APIs. On device implementations that declare support for OpenGL ES 3.0, 3.1, or 3.2 libGLESv2.so MUST export the corresponding function symbols in addition to the OpenGL ES 2.0 function symbols.

Android provides an OpenGL ES extension pack with Java interfaces and native support for advanced graphics functionality such as tessellation and the ASTC texture compression format. Android device implementations MUST support the extension pack if the device supports OpenGL ES 3.2 and MAY support it otherwise. If the extension pack is supported in its entirety, the device MUST identify the support through the android.hardware.opengles.aep feature flag.

Also, device implementations MAY implement any desired OpenGL ES extensions. However, device implementations MUST report via the OpenGL ES managed and native APIs all extension strings that they do support, and conversely MUST NOT report extension strings that they do not support.

Note that Android includes support for applications to optionally specify that they require specific OpenGL texture compression formats. These formats are typically vendor-specific. Device implementations are not required by Android to implement any specific texture compression format. However, they SHOULD accurately report any texture compression formats that they do support, via the getString() method in the OpenGL API.

Android includes a mechanism for applications to declare that they want to enable hardware acceleration for 2D graphics at the Application, Activity, Window, or View level through the use of a manifest tag android:hardwareAccelerated or direct API calls.

Device implementations MUST enable hardware acceleration by default, and MUST disable hardware acceleration if the developer so requests by setting android:hardwareAccelerated="false” or disabling hardware acceleration directly through the Android View APIs.

In addition, device implementations MUST exhibit behavior consistent with the Android SDK documentation on hardware acceleration .

Android includes a TextureView object that lets developers directly integrate hardware-accelerated OpenGL ES textures as rendering targets in a UI hierarchy. Device implementations MUST support the TextureView API, and MUST exhibit consistent behavior with the upstream Android implementation.

Android includes support for EGL_ANDROID_RECORDABLE, an EGLConfig attribute that indicates whether the EGLConfig supports rendering to an ANativeWindow that records images to a video. Device implementations MUST support EGL_ANDROID_RECORDABLE extension.

7.1.5. Legacy Application Compatibility Mode

Android specifies a “compatibility mode” in which the framework operates in a 'normal' screen size equivalent (320dp width) mode for the benefit of legacy applications not developed for old versions of Android that pre-date screen-size independence.

  • Android Automotive does not support legacy compatibility mode.
  • All other device implementations MUST include support for legacy application compatibility mode as implemented by the upstream Android open source code. That is, device implementations MUST NOT alter the triggers or thresholds at which compatibility mode is activated, and MUST NOT alter the behavior of the compatibility mode itself.

7.1.6. Screen Technology

The Android platform includes APIs that allow applications to render rich graphics to the display. Devices MUST support all of these APIs as defined by the Android SDK unless specifically allowed in this document.

  • Devices MUST support displays capable of rendering 16-bit color graphics and SHOULD support displays capable of 24-bit color graphics.
  • Devices MUST support displays capable of rendering animations.
  • The display technology used MUST have a pixel aspect ratio (PAR) between 0.9 and 1.15. That is, the pixel aspect ratio MUST be near square (1.0) with a 10 ~ 15% tolerance.

7.1.7. Secondary Displays

Android includes support for secondary display to enable media sharing capabilities and developer APIs for accessing external displays. If a device supports an external display either via a wired, wireless, or an embedded additional display connection then the device implementation MUST implement the display manager API as described in the Android SDK documentation.

7.2. Input Devices

Devices MUST support a touchscreen or meet the requirements listed in 7.2.2 for non-touch navigation.

7.2.1. Keyboard

Android Watch and Android Automotive implementations MAY implement a soft keyboard. All other device implementations MUST implement a soft keyboard and:

Implementaciones de dispositivos:

  • MUST include support for the Input Management Framework (which allows third-party developers to create Input Method Editors—ie soft keyboard) as detailed at http://developer.android.com .
  • MUST provide at least one soft keyboard implementation (regardless of whether a hard keyboard is present) except for Android Watch devices where the screen size makes it less reasonable to have a soft keyboard.
  • MAY include additional soft keyboard implementations.
  • MAY include a hardware keyboard.
  • MUST NOT include a hardware keyboard that does not match one of the formats specified in android.content.res.Configuration.keyboard (QWERTY or 12-key).

7.2.2. Non-touch Navigation

Android Television devices MUST support D-pad.

Implementaciones de dispositivos:

  • MAY omit a non-touch navigation option (trackball, d-pad, or wheel) if the device implementation is not an Android Television device.
  • MUST report the correct value for android.content.res.Configuration.navigation .
  • MUST provide a reasonable alternative user interface mechanism for the selection and editing of text, compatible with Input Management Engines. The upstream Android open source implementation includes a selection mechanism suitable for use with devices that lack non-touch navigation inputs.

7.2.3. Navigation Keys

The availability and visibility requirement of the Home, Recents, and Back functions differ between device types as described in this section.

The Home, Recents, and Back functions (mapped to the key events KEYCODE_HOME, KEYCODE_APP_SWITCH, KEYCODE_BACK, respectively) are essential to the Android navigation paradigm and therefore:

  • Android Handheld device implementations MUST provide the Home, Recents, and Back functions.
  • Android Television device implementations MUST provide the Home and Back functions.
  • Android Watch device implementations MUST have the Home function available to the user, and the Back function except for when it is in UI_MODE_TYPE_WATCH .
  • Android Watch device implementations, and no other Android device types, MAY consume the long press event on the key event KEYCODE_BACK and omit it from being sent to the foreground application.
  • Android Automotive implementations MUST provide the Home function and MAY provide Back and Recent functions.
  • All other types of device implementations MUST provide the Home and Back functions.

These functions MAY be implemented via dedicated physical buttons (such as mechanical or capacitive touch buttons), or MAY be implemented using dedicated software keys on a distinct portion of the screen, gestures, touch panel, etc. Android supports both implementations. All of these functions MUST be accessible with a single action (eg tap, double-click or gesture) when visible.

Recents function, if provided, MUST have a visible button or icon unless hidden together with other navigation functions in full-screen mode. This does not apply to devices upgrading from earlier Android versions that have physical buttons for navigation and no recents key.

The Home and Back functions, if provided, MUST each have a visible button or icon unless hidden together with other navigation functions in full-screen mode or when the uiMode UI_MODE_TYPE_MASK is set to UI_MODE_TYPE_WATCH.

The Menu function is deprecated in favor of action bar since Android 4.0. Therefore the new device implementations shipping with Android 7.1 and later MUST NOT implement a dedicated physical button for the Menu function. Older device implementations SHOULD NOT implement a dedicated physical button for the Menu function, but if the physical Menu button is implemented and the device is running applications with targetSdkVersion > 10, the device implementation:

  • MUST display the action overflow button on the action bar when it is visible and the resulting action overflow menu popup is not empty. For a device implementation launched before Android 4.4 but upgrading to Android 7.1, this is RECOMMENDED.
  • MUST NOT modify the position of the action overflow popup displayed by selecting the overflow button in the action bar.
  • MAY render the action overflow popup at a modified position on the screen when it is displayed by selecting the physical menu button.

For backwards compatibility, device implementations MUST make the Menu function available to applications when targetSdkVersion is less than 10, either by a physical button, a software key, or gestures. This Menu function should be presented unless hidden together with other navigation functions.

Android device implementations supporting the Assist action and/or VoiceInteractionService MUST be able to launch an assist app with a single interaction (eg tap, double-click, or gesture) when other navigation keys are visible. It is STRONGLY RECOMMENDED to use long press on home as this interaction. The designated interaction MUST launch the user-selected assist app, in other words the app that implements a VoiceInteractionService, or an activity handling the ACTION_ASSIST intent.

Device implementations MAY use a distinct portion of the screen to display the navigation keys, but if so, MUST meet these requirements:

  • Device implementation navigation keys MUST use a distinct portion of the screen, not available to applications, and MUST NOT obscure or otherwise interfere with the portion of the screen available to applications.
  • Device implementations MUST make available a portion of the display to applications that meets the requirements defined in section 7.1.1 .
  • Device implementations MUST display the navigation keys when applications do not specify a system UI mode, or specify SYSTEM_UI_FLAG_VISIBLE.
  • Device implementations MUST present the navigation keys in an unobtrusive “low profile” (eg. dimmed) mode when applications specify SYSTEM_UI_FLAG_LOW_PROFILE.
  • Device implementations MUST hide the navigation keys when applications specify SYSTEM_UI_FLAG_HIDE_NAVIGATION.

7.2.4. Touchscreen Input

Android Handhelds and Watch Devices MUST support touchscreen input.

Device implementations SHOULD have a pointer input system of some kind (either mouse-like or touch). However, if a device implementation does not support a pointer input system, it MUST NOT report the android.hardware.touchscreen or android.hardware.faketouch feature constant. Device implementations that do include a pointer input system:

  • SHOULD support fully independently tracked pointers, if the device input system supports multiple pointers.
  • MUST report the value of android.content.res.Configuration.touchscreen corresponding to the type of the specific touchscreen on the device.

Android includes support for a variety of touchscreens, touch pads, and fake touch input devices. Touchscreen-based device implementations are associated with a display such that the user has the impression of directly manipulating items on screen. Since the user is directly touching the screen, the system does not require any additional affordances to indicate the objects being manipulated. In contrast, a fake touch interface provides a user input system that approximates a subset of touchscreen capabilities. For example, a mouse or remote control that drives an on-screen cursor approximates touch, but requires the user to first point or focus then click. Numerous input devices like the mouse, trackpad, gyro-based air mouse, gyro-pointer, joystick, and multi-touch trackpad can support fake touch interactions. Android includes the feature constant android.hardware.faketouch, which corresponds to a high-fidelity non-touch (pointer-based) input device such as a mouse or trackpad that can adequately emulate touch-based input (including basic gesture support), and indicates that the device supports an emulated subset of touchscreen functionality. Device implementations that declare the fake touch feature MUST meet the fake touch requirements in section 7.2.5 .

Device implementations MUST report the correct feature corresponding to the type of input used. Device implementations that include a touchscreen (single-touch or better) MUST report the platform feature constant android.hardware.touchscreen. Device implementations that report the platform feature constant android.hardware.touchscreen MUST also report the platform feature constant android.hardware.faketouch. Device implementations that do not include a touchscreen (and rely on a pointer device only) MUST NOT report any touchscreen feature, and MUST report only android.hardware.faketouch if they meet the fake touch requirements in section 7.2.5 .

7.2.5. Fake Touch Input

Device implementations that declare support for android.hardware.faketouch:

  • MUST report the absolute X and Y screen positions of the pointer location and display a visual pointer on the screen.
  • MUST report touch event with the action code that specifies the state change that occurs on the pointer going down or up on the screen .
  • MUST support pointer down and up on an object on the screen, which allows users to emulate tap on an object on the screen.
  • MUST support pointer down, pointer up, pointer down then pointer up in the same place on an object on the screen within a time threshold, which allows users to emulate double tap on an object on the screen.
  • MUST support pointer down on an arbitrary point on the screen, pointer move to any other arbitrary point on the screen, followed by a pointer up, which allows users to emulate a touch drag.
  • MUST support pointer down then allow users to quickly move the object to a different position on the screen and then pointer up on the screen, which allows users to fling an object on the screen.

Devices that declare support for android.hardware.faketouch.multitouch.distinct MUST meet the requirements for faketouch above, and MUST also support distinct tracking of two or more independent pointer inputs.

7.2.6. Game Controller Support

Android Television device implementations MUST support button mappings for game controllers as listed below. The upstream Android implementation includes implementation for game controllers that satisfies this requirement.

7.2.6.1. Button Mappings

Android Television device implementations MUST support the following key mappings:

Button HID Usage 2 Android Button
A 1 0x09 0x0001 KEYCODE_BUTTON_A (96)
B 1 0x09 0x0002 KEYCODE_BUTTON_B (97)
X 1 0x09 0x0004 KEYCODE_BUTTON_X (99)
Y 1 0x09 0x0005 KEYCODE_BUTTON_Y (100)
D-pad up 1
D-pad down 1
0x01 0x0039 3 AXIS_HAT_Y 4
D-pad left 1
D-pad right 1
0x01 0x0039 3 AXIS_HAT_X 4
Left shoulder button 1 0x09 0x0007 KEYCODE_BUTTON_L1 (102)
Right shoulder button 1 0x09 0x0008 KEYCODE_BUTTON_R1 (103)
Left stick click 1 0x09 0x000E KEYCODE_BUTTON_THUMBL (106)
Right stick click 1 0x09 0x000F KEYCODE_BUTTON_THUMBR (107)
Home 1 0x0c 0x0223 KEYCODE_HOME (3)
Back 1 0x0c 0x0224 KEYCODE_BACK (4)

1 KeyEvent

2 The above HID usages must be declared within a Game pad CA (0x01 0x0005).

3 This usage must have a Logical Minimum of 0, a Logical Maximum of 7, a Physical Minimum of 0, a Physical Maximum of 315, Units in Degrees, and a Report Size of 4. The logical value is defined to be the clockwise rotation away from the vertical axis; for example, a logical value of 0 represents no rotation and the up button being pressed, while a logical value of 1 represents a rotation of 45 degrees and both the up and left keys being pressed.

4 MotionEvent

Analog Controls 1 HID Usage Android Button
Left Trigger 0x02 0x00C5 AXIS_LTRIGGER
Right Trigger 0x02 0x00C4 AXIS_RTRIGGER
Left Joystick 0x01 0x0030
0x01 0x0031
AXIS_X
AXIS_Y
Right Joystick 0x01 0x0032
0x01 0x0035
AXIS_Z
AXIS_RZ

1 MotionEvent

7.2.7. Remote Control

Android Television device implementations SHOULD provide a remote control to allow users to access the TV interface. The remote control MAY be a physical remote or can be a software-based remote that is accessible from a mobile phone or tablet. The remote control MUST meet the requirements defined below.

  • Search affordance . Device implementations MUST fire KEYCODE_SEARCH (or KEYCODE_ASSIST if the device supports an assistant) when the user invokes voice search on either the physical or software-based remote.
  • Navigation . All Android Television remotes MUST include Back, Home, and Select buttons and support for D-pad events .

7.3. Sensores

Android includes APIs for accessing a variety of sensor types. Devices implementations generally MAY omit these sensors, as provided for in the following subsections. If a device includes a particular sensor type that has a corresponding API for third-party developers, the device implementation MUST implement that API as described in the Android SDK documentation and the Android Open Source documentation on sensors . For example, device implementations:

  • MUST accurately report the presence or absence of sensors per the android.content.pm.PackageManager class.
  • MUST return an accurate list of supported sensors via the SensorManager.getSensorList() and similar methods.
  • MUST behave reasonably for all other sensor APIs (for example, by returning true or false as appropriate when applications attempt to register listeners, not calling sensor listeners when the corresponding sensors are not present; etc.).
  • MUST report all sensor measurements using the relevant International System of Units (metric) values for each sensor type as defined in the Android SDK documentation.
  • SHOULD report the event time in nanoseconds as defined in the Android SDK documentation, representing the time the event happened and synchronized with the SystemClock.elapsedRealtimeNano() clock. Existing and new Android devices are STRONGLY RECOMMENDED to meet these requirements so they will be able to upgrade to the future platform releases where this might become a REQUIRED component. The synchronization error SHOULD be below 100 milliseconds.
  • MUST report sensor data with a maximum latency of 100 milliseconds + 2 * sample_time for the case of a sensor streamed with a minimum required latency of 5 ms + 2 * sample_time when the application processor is active. This delay does not include any filtering delays.
  • MUST report the first sensor sample within 400 milliseconds + 2 * sample_time of the sensor being activated. It is acceptable for this sample to have an accuracy of 0.

The list above is not comprehensive; the documented behavior of the Android SDK and the Android Open Source Documentations on sensors is to be considered authoritative.

Some sensor types are composite, meaning they can be derived from data provided by one or more other sensors. (Examples include the orientation sensor and the linear acceleration sensor.) Device implementations SHOULD implement these sensor types, when they include the prerequisite physical sensors as described in sensor types . If a device implementation includes a composite sensor it MUST implement the sensor as described in the Android Open Source documentation on composite sensors .

Some Android sensors support a “continuous” trigger mode , which returns data continuously. For any API indicated by the Android SDK documentation to be a continuous sensor, device implementations MUST continuously provide periodic data samples that SHOULD have a jitter below 3%, where jitter is defined as the standard deviation of the difference of the reported timestamp values between consecutive events.

Note that the device implementations MUST ensure that the sensor event stream MUST NOT prevent the device CPU from entering a suspend state or waking up from a suspend state.

Finally, when several sensors are activated, the power consumption SHOULD NOT exceed the sum of the individual sensor's reported power consumption.

7.3.1. Acelerómetro

Device implementations SHOULD include a 3-axis accelerometer. Android Handheld devices, Android Automotive implementations, and Android Watch devices are STRONGLY RECOMMENDED to include this sensor. If a device implementation does include a 3-axis accelerometer, it:

  • MUST implement and report TYPE_ACCELEROMETER sensor .
  • MUST be able to report events up to a frequency of at least 50 Hz for Android Watch devices as such devices have a stricter power constraint and 100 Hz for all other device types.
  • SHOULD report events up to at least 200 Hz.
  • MUST comply with the Android sensor coordinate system as detailed in the Android APIs. Android Automotive implementations MUST comply with the Android car sensor coordinate system .
  • MUST be capable of measuring from freefall up to four times the gravity (4g) or more on any axis.
  • MUST have a resolution of at least 12-bits and SHOULD have a resolution of at least 16-bits.
  • SHOULD be calibrated while in use if the characteristics changes over the life cycle and compensated, and preserve the compensation parameters between device reboots.
  • SHOULD be temperature compensated.
  • MUST have a standard deviation no greater than 0.05 m/s^, where the standard deviation should be calculated on a per axis basis on samples collected over a period of at least 3 seconds at the fastest sampling rate.
  • SHOULD implement the TYPE_SIGNIFICANT_MOTION, TYPE_TILT_DETECTOR, TYPE_STEP_DETECTOR, TYPE_STEP_COUNTER composite sensors as described in the Android SDK document. Existing and new Android devices are STRONGLY RECOMMENDED to implement the TYPE_SIGNIFICANT_MOTION composite sensor. If any of these sensors are implemented, the sum of their power consumption MUST always be less than 4 mW and SHOULD each be below 2 mW and 0.5 mW for when the device is in a dynamic or static condition.
  • If a gyroscope sensor is included, MUST implement the TYPE_GRAVITY and TYPE_LINEAR_ACCELERATION composite sensors and SHOULD implement the TYPE_GAME_ROTATION_VECTOR composite sensor. Existing and new Android devices are STRONGLY RECOMMENDED to implement the TYPE_GAME_ROTATION_VECTOR sensor.
  • MUST implement a TYPE_ROTATION_VECTOR composite sensor, if a gyroscope sensor and a magnetometer sensor is also included.

7.3.2. Magnetometer

Device implementations SHOULD include a 3-axis magnetometer (compass). If a device does include a 3-axis magnetometer, it:

  • MUST implement the TYPE_MAGNETIC_FIELD sensor and SHOULD also implement TYPE_MAGNETIC_FIELD_UNCALIBRATED sensor. Existing and new Android devices are STRONGLY RECOMMENDED to implement the TYPE_MAGNETIC_FIELD_UNCALIBRATED sensor.
  • MUST be able to report events up to a frequency of at least 10 Hz and SHOULD report events up to at least 50 Hz.
  • MUST comply with the Android sensor coordinate system as detailed in the Android APIs.
  • MUST be capable of measuring between -900 µT and +900 µT on each axis before saturating.
  • MUST have a hard iron offset value less than 700 µT and SHOULD have a value below 200 µT, by placing the magnetometer far from dynamic (current-induced) and static (magnet-induced) magnetic fields.
  • MUST have a resolution equal or denser than 0.6 µT and SHOULD have a resolution equal or denser than 0.2 µT.
  • SHOULD be temperature compensated.
  • MUST support online calibration and compensation of the hard iron bias, and preserve the compensation parameters between device reboots.
  • MUST have the soft iron compensation applied—the calibration can be done either while in use or during the production of the device.
  • SHOULD have a standard deviation, calculated on a per axis basis on samples collected over a period of at least 3 seconds at the fastest sampling rate, no greater than 0.5 µT.
  • MUST implement a TYPE_ROTATION_VECTOR composite sensor, if an accelerometer sensor and a gyroscope sensor is also included.
  • MAY implement the TYPE_GEOMAGNETIC_ROTATION_VECTOR sensor if an accelerometer sensor is also implemented. However if implemented, it MUST consume less than 10 mW and SHOULD consume less than 3 mW when the sensor is registered for batch mode at 10 Hz.

7.3.3. GPS

Device implementations SHOULD include a GPS/GNSS receiver. If a device implementation does include a GPS/GNSS receiver and reports the capability to applications through the android.hardware.location.gps feature flag:

  • It is STRONGLY RECOMMENDED that the device continue to deliver normal GPS/GNSS outputs to applications during an emergency phone call and that location output not be blocked during an emergency phone call.
  • It MUST support location outputs at a rate of at least 1 Hz when requested via LocationManager#requestLocationUpdate .
  • It MUST be able to determine the location in open-sky conditions (strong signals, negligible multipath, HDOP < 2) within 10 seconds (fast time to first fix), when connected to a 0.5 Mbps or faster data speed internet connection. This requirement is typically met by the use of some form of Assisted or Predicted GPS/GNSS technique to minimize GPS/GNSS lock-on time (Assistance data includes Reference Time, Reference Location and Satellite Ephemeris/Clock).
    • After making such a location calculation, it is STRONGLY RECOMMENDED for the device to be able to determine its location, in open sky, within 10 seconds, when location requests are restarted, up to an hour after the initial location calculation, even when the subsequent request is made without a data connection, and/or after a power cycle.
  • In open sky conditions after determining the location, while stationary or moving with less than 1 meter per second squared of acceleration:
    • It MUST be able to determine location within 20 meters, and speed within 0.5 meters per second, at least 95% of the time.
    • It MUST simultaneously track and report via GnssStatus.Callback at least 8 satellites from one constellation.
    • It SHOULD be able to simultaneously track at least 24 satellites, from multiple constellations (eg GPS + at least one of Glonass, Beidou, Galileo).
  • It MUST report the GNSS technology generation through the test API 'getGnssYearOfHardware'.
  • It is STRONGLY RECOMMENDED to meet and MUST meet all requirements below if the GNSS technology generation is reported as the year "2016" or newer.
    • It MUST report GPS measurements, as soon as they are found, even if a location calculated from GPS/GNSS is not yet reported.
    • It MUST report GPS pseudoranges and pseudorange rates, that, in open-sky conditions after determining the location, while stationary or moving with less than 0.2 meter per second squared of acceleration, are sufficient to calculate position within 20 meters, and speed within 0.2 meters per second, at least 95% of the time.

Note that while some of the GPS requirements above are stated as STRONGLY RECOMMENDED, the Compatibility Definition for the next major version is expected to change these to a MUST.

7.3.4. Gyroscope

Device implementations SHOULD include a gyroscope (angular change sensor). Devices SHOULD NOT include a gyroscope sensor unless a 3-axis accelerometer is also included. If a device implementation includes a gyroscope, it:

  • MUST implement the TYPE_GYROSCOPE sensor and SHOULD also implement TYPE_GYROSCOPE_UNCALIBRATED sensor. Existing and new Android devices are STRONGLY RECOMMENDED to implement the SENSOR_TYPE_GYROSCOPE_UNCALIBRATED sensor.
  • MUST be capable of measuring orientation changes up to 1,000 degrees per second.
  • MUST be able to report events up to a frequency of at least 50 Hz for Android Watch devices as such devices have a stricter power constraint and 100 Hz for all other device types.
  • SHOULD report events up to at least 200 Hz.
  • MUST have a resolution of 12-bits or more and SHOULD have a resolution of 16-bits or more.
  • MUST be temperature compensated.
  • MUST be calibrated and compensated while in use, and preserve the compensation parameters between device reboots.
  • MUST have a variance no greater than 1e-7 rad^2 / s^2 per Hz (variance per Hz, or rad^2 / s). The variance is allowed to vary with the sampling rate, but must be constrained by this value. In other words, if you measure the variance of the gyro at 1 Hz sampling rate it should be no greater than 1e-7 rad^2/s^2.
  • MUST implement a TYPE_ROTATION_VECTOR composite sensor, if an accelerometer sensor and a magnetometer sensor is also included.
  • If an accelerometer sensor is included, MUST implement the TYPE_GRAVITY and TYPE_LINEAR_ACCELERATION composite sensors and SHOULD implement the TYPE_GAME_ROTATION_VECTOR composite sensor. Existing and new Android devices are STRONGLY RECOMMENDED to implement the TYPE_GAME_ROTATION_VECTOR sensor.

7.3.5. Barometer

Device implementations SHOULD include a barometer (ambient air pressure sensor). If a device implementation includes a barometer, it:

  • MUST implement and report TYPE_PRESSURE sensor.
  • MUST be able to deliver events at 5 Hz or greater.
  • MUST have adequate precision to enable estimating altitude.
  • MUST be temperature compensated.

7.3.6. Thermometer

Device implementations MAY include an ambient thermometer (temperature sensor). If present, it MUST be defined as SENSOR_TYPE_AMBIENT_TEMPERATURE and it MUST measure the ambient (room) temperature in degrees Celsius.

Device implementations MAY but SHOULD NOT include a CPU temperature sensor. If present, it MUST be defined as SENSOR_TYPE_TEMPERATURE, it MUST measure the temperature of the device CPU, and it MUST NOT measure any other temperature. Note the SENSOR_TYPE_TEMPERATURE sensor type was deprecated in Android 4.0.

For Android Automotive implementations, SENSOR_TYPE_AMBIENT_TEMPERATURE MUST measure the temperature inside the vehicle cabin.

7.3.7. Photometer

Device implementations MAY include a photometer (ambient light sensor).

7.3.8. Proximity Sensor

Device implementations MAY include a proximity sensor. Devices that can make a voice call and indicate any value other than PHONE_TYPE_NONE in getPhoneType SHOULD include a proximity sensor. If a device implementation does include a proximity sensor, it:

  • MUST measure the proximity of an object in the same direction as the screen. That is, the proximity sensor MUST be oriented to detect objects close to the screen, as the primary intent of this sensor type is to detect a phone in use by the user. If a device implementation includes a proximity sensor with any other orientation, it MUST NOT be accessible through this API.
  • MUST have 1-bit of accuracy or more.

7.3.9. High Fidelity Sensors

Device implementations supporting a set of higher quality sensors that can meet all the requirements listed in this section MUST identify the support through the android.hardware.sensor.hifi_sensors feature flag.

A device declaring android.hardware.sensor.hifi_sensors MUST support all of the following sensor types meeting the quality requirements as below:

  • SENSOR_TYPE_ACCELEROMETER
    • MUST have a measurement range between at least -8g and +8g.
    • MUST have a measurement resolution of at least 1024 LSB/G.
    • MUST have a minimum measurement frequency of 12.5 Hz or lower.
    • MUST have a maximum measurement frequency of 400 Hz or higher.
    • MUST have a measurement noise not above 400 uG/√Hz.
    • MUST implement a non-wake-up form of this sensor with a buffering capability of at least 3000 sensor events.
    • MUST have a batching power consumption not worse than 3 mW.
    • SHOULD have a stationary noise bias stability of \<15 μg √Hz from 24hr static dataset.
    • SHOULD have a bias change vs. temperature of ≤ +/- 1mg / °C.
    • SHOULD have a best-fit line non-linearity of ≤ 0.5%, and sensitivity change vs. temperature of ≤ 0.03%/C°.
  • SENSOR_TYPE_GYROSCOPE

    • MUST have a measurement range between at least -1000 and +1000 dps.
    • MUST have a measurement resolution of at least 16 LSB/dps.
    • MUST have a minimum measurement frequency of 12.5 Hz or lower.
    • MUST have a maximum measurement frequency of 400 Hz or higher.
    • MUST have a measurement noise not above 0.014°/s/√Hz.
    • SHOULD have a stationary bias stability of < 0.0002 °/s √Hz from 24-hour static dataset.
    • SHOULD have a bias change vs. temperature of ≤ +/- 0.05 °/ s / °C.
    • SHOULD have a sensitivity change vs. temperature of ≤ 0.02% / °C.
    • SHOULD have a best-fit line non-linearity of ≤ 0.2%.
    • SHOULD have a noise density of ≤ 0.007 °/s/√Hz.
  • SENSOR_TYPE_GYROSCOPE_UNCALIBRATED with the same quality requirements as SENSOR_TYPE_GYROSCOPE.

  • SENSOR_TYPE_GEOMAGNETIC_FIELD
    • MUST have a measurement range between at least -900 and +900 uT.
    • MUST have a measurement resolution of at least 5 LSB/uT.
    • MUST have a minimum measurement frequency of 5 Hz or lower.
    • MUST have a maximum measurement frequency of 50 Hz or higher.
    • MUST have a measurement noise not above 0.5 uT.
  • SENSOR_TYPE_MAGNETIC_FIELD_UNCALIBRATED with the same quality requirements as SENSOR_TYPE_GEOMAGNETIC_FIELD and in addition:
    • MUST implement a non-wake-up form of this sensor with a buffering capability of at least 600 sensor events.
  • SENSOR_TYPE_PRESSURE
    • MUST have a measurement range between at least 300 and 1100 hPa.
    • MUST have a measurement resolution of at least 80 LSB/hPa.
    • MUST have a minimum measurement frequency of 1 Hz or lower.
    • MUST have a maximum measurement frequency of 10 Hz or higher.
    • MUST have a measurement noise not above 2 Pa/√Hz.
    • MUST implement a non-wake-up form of this sensor with a buffering capability of at least 300 sensor events.
    • MUST have a batching power consumption not worse than 2 mW.
  • SENSOR_TYPE_GAME_ROTATION_VECTOR
    • MUST implement a non-wake-up form of this sensor with a buffering capability of at least 300 sensor events.
    • MUST have a batching power consumption not worse than 4 mW.
  • SENSOR_TYPE_SIGNIFICANT_MOTION
    • MUST have a power consumption not worse than 0.5 mW when device is static and 1.5 mW when device is moving.
  • SENSOR_TYPE_STEP_DETECTOR
    • MUST implement a non-wake-up form of this sensor with a buffering capability of at least 100 sensor events.
    • MUST have a power consumption not worse than 0.5 mW when device is static and 1.5 mW when device is moving.
    • MUST have a batching power consumption not worse than 4 mW.
  • SENSOR_TYPE_STEP_COUNTER
    • MUST have a power consumption not worse than 0.5 mW when device is static and 1.5 mW when device is moving.
  • SENSOR_TILT_DETECTOR
    • MUST have a power consumption not worse than 0.5 mW when device is static and 1.5 mW when device is moving.

Also such a device MUST meet the following sensor subsystem requirements:

  • The event timestamp of the same physical event reported by the Accelerometer, Gyroscope sensor and Magnetometer MUST be within 2.5 milliseconds of each other.
  • The Gyroscope sensor event timestamps MUST be on the same time base as the camera subsystem and within 1 milliseconds of error.
  • High Fidelity sensors MUST deliver samples to applications within 5 milliseconds from the time when the data is available on the physical sensor to the application.
  • The power consumption MUST not be higher than 0.5 mW when device is static and 2.0 mW when device is moving when any combination of the following sensors are enabled:
    • SENSOR_TYPE_SIGNIFICANT_MOTION
    • SENSOR_TYPE_STEP_DETECTOR
    • SENSOR_TYPE_STEP_COUNTER
    • SENSOR_TILT_DETECTORS

Note that all power consumption requirements in this section do not include the power consumption of the Application Processor. It is inclusive of the power drawn by the entire sensor chain—the sensor, any supporting circuitry, any dedicated sensor processing system, etc.

The following sensor types MAY also be supported on a device implementation declaring android.hardware.sensor.hifi_sensors, but if these sensor types are present they MUST meet the following minimum buffering capability requirement:

  • SENSOR_TYPE_PROXIMITY: 100 sensor events

7.3.10. Fingerprint Sensor

Device implementations with a secure lock screen SHOULD include a fingerprint sensor. If a device implementation includes a fingerprint sensor and has a corresponding API for third-party developers, it:

  • MUST declare support for the android.hardware.fingerprint feature.
  • MUST fully implement the corresponding API as described in the Android SDK documentation.
  • MUST have a false acceptance rate not higher than 0.002%.
  • Is STRONGLY RECOMMENDED to have a false rejection rate of less than 10%, as measured on the device
  • Is STRONGLY RECOMMENDED to have a latency below 1 second, measured from when the fingerprint sensor is touched until the screen is unlocked, for one enrolled finger.
  • MUST rate limit attempts for at least 30 seconds after five false trials for fingerprint verification.
  • MUST have a hardware-backed keystore implementation, and perform the fingerprint matching in a Trusted Execution Environment (TEE) or on a chip with a secure channel to the TEE.
  • MUST have all identifiable fingerprint data encrypted and cryptographically authenticated such that they cannot be acquired, read or altered outside of the Trusted Execution Environment (TEE) as documented in the implementation guidelines on the Android Open Source Project site.
  • MUST prevent adding a fingerprint without first establishing a chain of trust by having the user confirm existing or add a new device credential (PIN/pattern/password) that's secured by TEE; the Android Open Source Project implementation provides the mechanism in the framework to do so.
  • MUST NOT enable 3rd-party applications to distinguish between individual fingerprints.
  • MUST honor the DevicePolicyManager.KEYGUARD_DISABLE_FINGERPRINT flag.
  • MUST, when upgraded from a version earlier than Android 6.0, have the fingerprint data securely migrated to meet the above requirements or removed.
  • SHOULD use the Android Fingerprint icon provided in the Android Open Source Project.

7.3.11. Android Automotive-only sensors

Automotive-specific sensors are defined in the android.car.CarSensorManager API .

7.3.11.1. Current Gear

Android Automotive implementations SHOULD provide current gear as SENSOR_TYPE_GEAR.

7.3.11.2. Day Night Mode

Android Automotive implementations MUST support day/night mode defined as SENSOR_TYPE_NIGHT. The value of this flag MUST be consistent with dashboard day/night mode and SHOULD be based on ambient light sensor input. The underlying ambient light sensor MAY be the same as Photometer .

7.3.11.3. Driving Status

Android Automotive implementations MUST support driving status defined as SENSOR_TYPE_DRIVING_STATUS, with a default value of DRIVE_STATUS_UNRESTRICTED when the vehicle is fully stopped and parked. It is the responsibility of device manufacturers to configure SENSOR_TYPE_DRIVING_STATUS in compliance with all laws and regulations that apply to markets where the product is shipping.

7.3.11.4. Wheel Speed

Android Automotive implementations MUST provide vehicle speed defined as SENSOR_TYPE_CAR_SPEED.

7.3.12. Pose Sensor

Device implementations MAY support pose sensor with 6 degrees of freedom. Android Handheld devices are RECOMMENDED to support this sensor. If a device implementation does support pose sensor with 6 degrees of freedom, it:

  • MUST implement and report TYPE_POSE_6DOF sensor.
  • MUST be more accurate than the rotation vector alone.

7.4. Data Connectivity

7.4.1. Telephony

“Telephony” as used by the Android APIs and this document refers specifically to hardware related to placing voice calls and sending SMS messages via a GSM or CDMA network. While these voice calls may or may not be packet-switched, they are for the purposes of Android considered independent of any data connectivity that may be implemented using the same network. In other words, the Android “telephony” functionality and APIs refer specifically to voice calls and SMS. For instance, device implementations that cannot place calls or send/receive SMS messages MUST NOT report the android.hardware.telephony feature or any subfeatures, regardless of whether they use a cellular network for data connectivity.

Android MAY be used on devices that do not include telephony hardware. That is, Android is compatible with devices that are not phones. However, if a device implementation does include GSM or CDMA telephony, it MUST implement full support for the API for that technology. Device implementations that do not include telephony hardware MUST implement the full APIs as no-ops.

7.4.1.1. Number Blocking Compatibility

Android Telephony device implementations MUST include number blocking support and:

  • MUST fully implement BlockedNumberContract and the corresponding API as described in the SDK documentation.
  • MUST block all calls and messages from a phone number in 'BlockedNumberProvider' without any interaction with apps. The only exception is when number blocking is temporarily lifted as described in the SDK documentation.
  • MUST NOT write to the platform call log provider for a blocked call.
  • MUST NOT write to the Telephony provider for a blocked message.
  • MUST implement a blocked numbers management UI, which is opened with the intent returned by TelecomManager.createManageBlockedNumbersIntent() method.
  • MUST NOT allow secondary users to view or edit the blocked numbers on the device as the Android platform assumes the primary user to have full control of the telephony services, a single instance, on the device. All blocking related UI MUST be hidden for secondary users and the blocked list MUST still be respected.
  • SHOULD migrate the blocked numbers into the provider when a device updates to Android 7.0.

7.4.2. IEEE 802.11 (Wi-Fi)

All Android device implementations SHOULD include support for one or more forms of 802.11. If a device implementation does include support for 802.11 and exposes the functionality to a third-party application, it MUST implement the corresponding Android API and:

  • MUST report the hardware feature flag android.hardware.wifi.
  • MUST implement the multicast API as described in the SDK documentation.
  • MUST support multicast DNS (mDNS) and MUST NOT filter mDNS packets (224.0.0.251) at any time of operation including:
    • Even when the screen is not in an active state.
    • For Android Television device implementations, even when in standby power states.

7.4.2.1. Wi-Fi directo

Device implementations SHOULD include support for Wi-Fi Direct (Wi-Fi peer-to-peer). If a device implementation does include support for Wi-Fi Direct, it MUST implement the corresponding Android API as described in the SDK documentation. If a device implementation includes support for Wi-Fi Direct, then it:

  • MUST report the hardware feature android.hardware.wifi.direct.
  • MUST support regular Wi-Fi operation.
  • SHOULD support concurrent Wi-Fi and Wi-Fi Direct operation.

Device implementations SHOULD include support for Wi-Fi Tunneled Direct Link Setup (TDLS) as described in the Android SDK Documentation. If a device implementation does include support for TDLS and TDLS is enabled by the WiFiManager API, the device:

  • SHOULD use TDLS only when it is possible AND beneficial.
  • SHOULD have some heuristic and NOT use TDLS when its performance might be worse than going through the Wi-Fi access point.

7.4.3. Bluetooth

Android Watch implementations MUST support Bluetooth. Android Television implementations MUST support Bluetooth and Bluetooth LE. Android Automotive implementations MUST support Bluetooth and SHOULD support Bluetooth LE.

Device implementations that support android.hardware.vr.high_performance feature MUST support Bluetooth 4.2 and Bluetooth LE Data Length Extension.

Android includes support for Bluetooth and Bluetooth Low Energy . Device implementations that include support for Bluetooth and Bluetooth Low Energy MUST declare the relevant platform features (android.hardware.bluetooth and android.hardware.bluetooth_le respectively) and implement the platform APIs. Device implementations SHOULD implement relevant Bluetooth profiles such as A2DP, AVCP, OBEX, etc. as appropriate for the device.

Android Automotive implementations SHOULD support Message Access Profile (MAP). Android Automotive implementations MUST support the following Bluetooth profiles:

  • Phone calling over Hands-Free Profile (HFP).
  • Media playback over Audio Distribution Profile (A2DP).
  • Media playback control over Remote Control Profile (AVRCP).
  • Contact sharing using the Phone Book Access Profile (PBAP).

Device implementations including support for Bluetooth Low Energy:

  • MUST declare the hardware feature android.hardware.bluetooth_le.
  • MUST enable the GATT (generic attribute profile) based Bluetooth APIs as described in the SDK documentation and android.bluetooth .
  • are STRONGLY RECOMMENDED to implement a Resolvable Private Address (RPA) timeout no longer than 15 minutes and rotate the address at timeout to protect user privacy.
  • SHOULD support offloading of the filtering logic to the bluetooth chipset when implementing the ScanFilter API , and MUST report the correct value of where the filtering logic is implemented whenever queried via the android.bluetooth.BluetoothAdapter.isOffloadedFilteringSupported() method.
  • SHOULD support offloading of the batched scanning to the bluetooth chipset, but if not supported, MUST report 'false' whenever queried via the android.bluetooth.BluetoothAdapter.isOffloadedScanBatchingSupported() method.
  • SHOULD support multi advertisement with at least 4 slots, but if not supported, MUST report 'false' whenever queried via the android.bluetooth.BluetoothAdapter.isMultipleAdvertisementSupported() method.

7.4.4. Near-Field Communications

Device implementations SHOULD include a transceiver and related hardware for Near-Field Communications (NFC). If a device implementation does include NFC hardware and plans to make it available to third-party apps, then it:

  • MUST report the android.hardware.nfc feature from the android.content.pm.PackageManager.hasSystemFeature() method .
  • MUST be capable of reading and writing NDEF messages via the following NFC standards:
    • MUST be capable of acting as an NFC Forum reader/writer (as defined by the NFC Forum technical specification NFCForum-TS-DigitalProtocol-1.0) via the following NFC standards:
      • NfcA (ISO14443-3A)
      • NfcB (ISO14443-3B)
      • NfcF (JIS X 6319-4)
      • IsoDep (ISO 14443-4)
      • NFC Forum Tag Types 1, 2, 3, 4 (defined by the NFC Forum)
    • STRONGLY RECOMMENDED to be capable of reading and writing NDEF messages as well as raw data via the following NFC standards. Note that while the NFC standards below are stated as STRONGLY RECOMMENDED, the Compatibility Definition for a future version is planned to change these to MUST. These standards are optional in this version but will be required in future versions. Existing and new devices that run this version of Android are very strongly encouraged to meet these requirements now so they will be able to upgrade to the future platform releases.
      • NfcV (ISO 15693)
    • SHOULD be capable of reading the barcode and URL (if encoded) of Thinfilm NFC Barcode products.
    • MUST be capable of transmitting and receiving data via the following peer-to-peer standards and protocols:
      • ISO 18092
      • LLCP 1.2 (defined by the NFC Forum)
      • SDP 1.0 (defined by the NFC Forum)
      • NDEF Push Protocol
      • SNEP 1.0 (defined by the NFC Forum)
    • MUST include support for Android Beam .
    • MUST implement the SNEP default server. Valid NDEF messages received by the default SNEP server MUST be dispatched to applications using the android.nfc.ACTION_NDEF_DISCOVERED intent. Disabling Android Beam in settings MUST NOT disable dispatch of incoming NDEF message.
    • MUST honor the android.settings.NFCSHARING_SETTINGS intent to show NFC sharing settings .
    • MUST implement the NPP server. Messages received by the NPP server MUST be processed the same way as the SNEP default server.
    • MUST implement a SNEP client and attempt to send outbound P2P NDEF to the default SNEP server when Android Beam is enabled. If no default SNEP server is found then the client MUST attempt to send to an NPP server.
    • MUST allow foreground activities to set the outbound P2P NDEF message using android.nfc.NfcAdapter.setNdefPushMessage, and android.nfc.NfcAdapter.setNdefPushMessageCallback, and android.nfc.NfcAdapter.enableForegroundNdefPush.
    • SHOULD use a gesture or on-screen confirmation, such as 'Touch to Beam', before sending outbound P2P NDEF messages.
    • SHOULD enable Android Beam by default and MUST be able to send and receive using Android Beam, even when another proprietary NFC P2p mode is turned on.
    • MUST support NFC Connection handover to Bluetooth when the device supports Bluetooth Object Push Profile. Device implementations MUST support connection handover to Bluetooth when using android.nfc.NfcAdapter.setBeamPushUris, by implementing the “ Connection Handover version 1.2 ” and “ Bluetooth Secure Simple Pairing Using NFC version 1.0 ” specs from the NFC Forum. Such an implementation MUST implement the handover LLCP service with service name “urn:nfc:sn:handover” for exchanging the handover request/select records over NFC, and it MUST use the Bluetooth Object Push Profile for the actual Bluetooth data transfer. For legacy reasons (to remain compatible with Android 4.1 devices), the implementation SHOULD still accept SNEP GET requests for exchanging the handover request/select records over NFC. However an implementation itself SHOULD NOT send SNEP GET requests for performing connection handover.
    • MUST poll for all supported technologies while in NFC discovery mode.
    • SHOULD be in NFC discovery mode while the device is awake with the screen active and the lock-screen unlocked.

(Note that publicly available links are not available for the JIS, ISO, and NFC Forum specifications cited above.)

Android includes support for NFC Host Card Emulation (HCE) mode. If a device implementation does include an NFC controller chipset capable of HCE (for NfcA and/or NfcB) and it supports Application ID (AID) routing, then it:

  • MUST report the android.hardware.nfc.hce feature constant.
  • MUST support NFC HCE APIs as defined in the Android SDK.

If a device implementation does include an NFC controller chipset capable of HCE for NfcF, and it implements the feature for third-party applications, then it:

  • MUST report the android.hardware.nfc.hcef feature constant.
  • MUST implement the [NfcF Card Emulation APIs] (https://developer.android.com/reference/android/nfc/cardemulation/NfcFCardEmulation.html) as defined in the Android SDK.

Additionally, device implementations MAY include reader/writer support for the following MIFARE technologies.

  • MIFARE Classic
  • MIFARE Ultralight
  • NDEF on MIFARE Classic

Note that Android includes APIs for these MIFARE types. If a device implementation supports MIFARE in the reader/writer role, it:

  • MUST implement the corresponding Android APIs as documented by the Android SDK.
  • MUST report the feature com.nxp.mifare from the android.content.pm.PackageManager.hasSystemFeature() method. Note that this is not a standard Android feature and as such does not appear as a constant in the android.content.pm.PackageManager class.
  • MUST NOT implement the corresponding Android APIs nor report the com.nxp.mifare feature unless it also implements general NFC support as described in this section.

If a device implementation does not include NFC hardware, it MUST NOT declare the android.hardware.nfc feature from the android.content.pm.PackageManager.hasSystemFeature() method, and MUST implement the Android NFC API as a no-op.

As the classes android.nfc.NdefMessage and android.nfc.NdefRecord represent a protocol-independent data representation format, device implementations MUST implement these APIs even if they do not include support for NFC or declare the android.hardware.nfc feature.

7.4.5. Minimum Network Capability

Device implementations MUST include support for one or more forms of data networking. Specifically, device implementations MUST include support for at least one data standard capable of 200Kbit/sec or greater. Examples of technologies that satisfy this requirement include EDGE, HSPA, EV-DO, 802.11g, Ethernet, Bluetooth PAN, etc.

Device implementations where a physical networking standard (such as Ethernet) is the primary data connection SHOULD also include support for at least one common wireless data standard, such as 802.11 (Wi-Fi).

Devices MAY implement more than one form of data connectivity.

Devices MUST include an IPv6 networking stack and support IPv6 communication using the managed APIs, such as java.net.Socket and java.net.URLConnection , as well as the native APIs, such as AF_INET6 sockets. The required level of IPv6 support depends on the network type, as follows:

  • Devices that support Wi-Fi networks MUST support dual-stack and IPv6-only operation on Wi-Fi.
  • Devices that support Ethernet networks MUST support dual-stack operation on Ethernet.
  • Devices that support cellular data SHOULD support IPv6 operation (IPv6-only and possibly dual-stack) on cellular data.
  • When a device is simultaneously connected to more than one network (eg, Wi-Fi and cellular data), it MUST simultaneously meet these requirements on each network to which it is connected.

IPv6 MUST be enabled by default.

In order to ensure that IPv6 communication is as reliable as IPv4, unicast IPv6 packets sent to the device MUST NOT be dropped, even when the screen is not in an active state. Redundant multicast IPv6 packets, such as repeated identical Router Advertisements, MAY be rate-limited in hardware or firmware if doing so is necessary to save power. In such cases, rate-limiting MUST NOT cause the device to lose IPv6 connectivity on any IPv6-compliant network that uses RA lifetimes of at least 180 seconds.

IPv6 connectivity MUST be maintained in doze mode.

7.4.6. Sync Settings

Device implementations MUST have the master auto-sync setting on by default so that the method getMasterSyncAutomatically() returns “true”.

7.4.7. Data Saver

Device implementations with a metered connection are STRONGLY RECOMMENDED to provide the data saver mode.

If a device implementation provides the data saver mode, it:

  • MUST support all the APIs in the ConnectivityManager class as described in the SDK documentation

  • MUST provide a user interface in the settings, allowing users to add applications to or remove applications from the whitelist.

Conversely if a device implementation does not provide the data saver mode, it:

  • MUST return the value RESTRICT_BACKGROUND_STATUS_DISABLED for ConnectivityManager.getRestrictBackgroundStatus()

  • MUST not broadcast ConnectivityManager.ACTION_RESTRICT_BACKGROUND_CHANGED

  • MUST have an activity that handles the Settings.ACTION_IGNORE_BACKGROUND_DATA_RESTRICTIONS_SETTINGS intent but MAY implement it as a no-op.

7.5. Cameras

Device implementations SHOULD include a rear-facing camera and MAY include a front-facing camera. A rear-facing camera is a camera located on the side of the device opposite the display; that is, it images scenes on the far side of the device, like a traditional camera. A front-facing camera is a camera located on the same side of the device as the display; that is, a camera typically used to image the user, such as for video conferencing and similar applications.

If a device implementation includes at least one camera, it MUST be possible for an application to simultaneously allocate 3 RGBA_8888 bitmaps equal to the size of the images produced by the largest-resolution camera sensor on the device, while camera is open for the purpose of basic preview and still capture.

7.5.1. Rear-Facing Camera

Device implementations SHOULD include a rear-facing camera. If a device implementation includes at least one rear-facing camera, it:

  • MUST report the feature flag android.hardware.camera and android.hardware.camera.any.
  • MUST have a resolution of at least 2 megapixels.
  • SHOULD have either hardware auto-focus or software auto-focus implemented in the camera driver (transparent to application software).
  • MAY have fixed-focus or EDOF (extended depth of field) hardware.
  • MAY include a flash. If the Camera includes a flash, the flash lamp MUST NOT be lit while an android.hardware.Camera.PreviewCallback instance has been registered on a Camera preview surface, unless the application has explicitly enabled the flash by enabling the FLASH_MODE_AUTO or FLASH_MODE_ON attributes of a Camera.Parameters object. Note that this constraint does not apply to the device's built-in system camera application, but only to third-party applications using Camera.PreviewCallback.

7.5.2. Front-Facing Camera

Device implementations MAY include a front-facing camera. If a device implementation includes at least one front-facing camera, it:

  • MUST report the feature flag android.hardware.camera.any and android.hardware.camera.front.
  • MUST have a resolution of at least VGA (640x480 pixels).
  • MUST NOT use a front-facing camera as the default for the Camera API. The camera API in Android has specific support for front-facing cameras and device implementations MUST NOT configure the API to to treat a front-facing camera as the default rear-facing camera, even if it is the only camera on the device.
  • MAY include features (such as auto-focus, flash, etc.) available to rear-facing cameras as described in section 7.5.1 .
  • MUST horizontally reflect (ie mirror) the stream displayed by an app in a CameraPreview, as follows:
    • If the device implementation is capable of being rotated by user (such as automatically via an accelerometer or manually via user input), the camera preview MUST be mirrored horizontally relative to the device's current orientation.
    • If the current application has explicitly requested that the Camera display be rotated via a call to the android.hardware.Camera.setDisplayOrientation() method, the camera preview MUST be mirrored horizontally relative to the orientation specified by the application.
    • Otherwise, the preview MUST be mirrored along the device's default horizontal axis.
  • MUST mirror the image displayed by the postview in the same manner as the camera preview image stream. If the device implementation does not support postview, this requirement obviously does not apply.
  • MUST NOT mirror the final captured still image or video streams returned to application callbacks or committed to media storage.

7.5.3. External Camera

Device implementations MAY include support for an external camera that is not necessarily always connected. If a device includes support for an external camera, it:

  • MUST declare the platform feature flag android.hardware.camera.external and android.hardware camera.any .
  • MAY support multiple cameras.
  • MUST support USB Video Class (UVC 1.0 or higher) if the external camera connects through the USB port.
  • SHOULD support video compressions such as MJPEG to enable transfer of high-quality unencoded streams (ie raw or independently compressed picture streams).
  • MAY support camera-based video encoding. If supported, a simultaneous unencoded / MJPEG stream (QVGA or greater resolution) MUST be accessible to the device implementation.

7.5.4. Camera API Behavior

Android includes two API packages to access the camera, the newer android.hardware.camera2 API expose lower-level camera control to the app, including efficient zero-copy burst/streaming flows and per-frame controls of exposure, gain, white balance gains, color conversion, denoising, sharpening, and more.

The older API package, android.hardware.Camera, is marked as deprecated in Android 5.0 but as it should still be available for apps to use Android device implementations MUST ensure the continued support of the API as described in this section and in the Android SDK.

Device implementations MUST implement the following behaviors for the camera-related APIs, for all available cameras:

  • If an application has never called android.hardware.Camera.Parameters.setPreviewFormat(int), then the device MUST use android.hardware.PixelFormat.YCbCr_420_SP for preview data provided to application callbacks.
  • If an application registers an android.hardware.Camera.PreviewCallback instance and the system calls the onPreviewFrame() method when the preview format is YCbCr_420_SP, the data in the byte[] passed into onPreviewFrame() must further be in the NV21 encoding format. That is, NV21 MUST be the default.
  • For android.hardware.Camera, device implementations MUST support the YV12 format (as denoted by the android.graphics.ImageFormat.YV12 constant) for camera previews for both front- and rear-facing cameras. (The hardware video encoder and camera may use any native pixel format, but the device implementation MUST support conversion to YV12.)
  • For android.hardware.camera2, device implementations must support the android.hardware.ImageFormat.YUV_420_888 and android.hardware.ImageFormat.JPEG formats as outputs through the android.media.ImageReader API.

Device implementations MUST still implement the full Camera API included in the Android SDK documentation, regardless of whether the device includes hardware autofocus or other capabilities. For instance, cameras that lack autofocus MUST still call any registered android.hardware.Camera.AutoFocusCallback instances (even though this has no relevance to a non-autofocus camera.) Note that this does apply to front-facing cameras; for instance, even though most front-facing cameras do not support autofocus, the API callbacks must still be “faked” as described.

Device implementations MUST recognize and honor each parameter name defined as a constant on the android.hardware.Camera.Parameters class, if the underlying hardware supports the feature. If the device hardware does not support a feature, the API must behave as documented. Conversely, device implementations MUST NOT honor or recognize string constants passed to the android.hardware.Camera.setParameters() method other than those documented as constants on the android.hardware.Camera.Parameters. That is, device implementations MUST support all standard Camera parameters if the hardware allows, and MUST NOT support custom Camera parameter types. For instance, device implementations that support image capture using high dynamic range (HDR) imaging techniques MUST support camera parameter Camera.SCENE_MODE_HDR.

Because not all device implementations can fully support all the features of the android.hardware.camera2 API, device implementations MUST report the proper level of support with the android.info.supportedHardwareLevel property as described in the Android SDK and report the appropriate framework feature flags .

Device implementations MUST also declare its Individual camera capabilities of android.hardware.camera2 via the android.request.availableCapabilities property and declare the appropriate feature flags ; a device must define the feature flag if any of its attached camera devices supports the feature.

Device implementations MUST broadcast the Camera.ACTION_NEW_PICTURE intent whenever a new picture is taken by the camera and the entry of the picture has been added to the media store.

Device implementations MUST broadcast the Camera.ACTION_NEW_VIDEO intent whenever a new video is recorded by the camera and the entry of the picture has been added to the media store.

7.5.5. Camera Orientation

Both front- and rear-facing cameras, if present, MUST be oriented so that the long dimension of the camera aligns with the screen's long dimension. That is, when the device is held in the landscape orientation, cameras MUST capture images in the landscape orientation. This applies regardless of the device's natural orientation; that is, it applies to landscape-primary devices as well as portrait-primary devices.

7.6. Memory and Storage

7.6.1. Minimum Memory and Storage

Android Television devices MUST have at least 4GB of non-volatile storage available for application private data.

The memory available to the kernel and userspace on device implementations MUST be at least equal or larger than the minimum values specified by the following table. (See section 7.1.1 for screen size and density definitions.)

Density and screen size 32-bit device 64-bit device
Android Watch devices (due to smaller screens) 416MB Not applicable
  • 280dpi or lower on small/normal screens
  • mdpi or lower on large screens
  • ldpi or lower on extra large screens
512 MB 816MB
  • xhdpi or higher on small/normal screens
  • hdpi or higher on large screens
  • mdpi or higher on extra large screens
608MB 944MB
  • 400dpi or higher on small/normal screens
  • xhdpi or higher on large screens
  • tvdpi or higher on extra large screens
896MB 1280MB
  • 560dpi or higher on small/normal screens
  • 400dpi or higher on large screens
  • xhdpi or higher on extra large screens
1344MB 1824MB

The minimum memory values MUST be in addition to any memory space already dedicated to hardware components such as radio, video, and so on that is not under the kernel's control.

Device implementations with less than 512MB of memory available to the kernel and userspace, unless an Android Watch, MUST return the value "true" for ActivityManager.isLowRamDevice().

Android Television devices MUST have at least 4GB and other device implementations MUST have at least 3GB of non-volatile storage available for application private data. That is, the /data partition MUST be at least 4GB for Android Television devices and at least 3GB for other device implementations. Device implementations that run Android are STRONGLY RECOMMENDED to have at least 4GB of non-volatile storage for application private data so they will be able to upgrade to the future platform releases.

The Android APIs include a Download Manager that applications MAY use to download data files. The device implementation of the Download Manager MUST be capable of downloading individual files of at least 100MB in size to the default “cache” location.

7.6.2. Application Shared Storage

Device implementations MUST offer shared storage for applications also often referred as “shared external storage”.

Device implementations MUST be configured with shared storage mounted by default, “out of the box”. If the shared storage is not mounted on the Linuxpath /sdcard, then the device MUST include a Linux symbolic link from /sdcard to the actual mount point.

Device implementations MAY have hardware for user-accessible removable storage, such as a Secure Digital (SD) card slot. If this slot is used to satisfy the shared storage requirement, the device implementation:

  • MUST implement a toast or pop-up user interface warning the user when there is no SD card.
  • MUST include a FAT-formatted SD card 1GB in size or larger OR show on the box and other material available at time of purchase that the SD card has to be separately purchased.
  • MUST mount the SD card by default.

Alternatively, device implementations MAY allocate internal (non-removable) storage as shared storage for apps as included in the upstream Android Open Source Project; device implementations SHOULD use this configuration and software implementation. If a device implementation uses internal (non-removable) storage to satisfy the shared storage requirement, while that storage MAY share space with the application private data, it MUST be at least 1GB in size and mounted on /sdcard (or /sdcard MUST be a symbolic link to the physical location if it is mounted elsewhere).

Device implementations MUST enforce as documented the android.permission.WRITE_EXTERNAL_STORAGE permission on this shared storage. Shared storage MUST otherwise be writable by any application that obtains that permission.

Device implementations that include multiple shared storage paths (such as both an SD card slot and shared internal storage) MUST allow only pre-installed & privileged Android applications with the WRITE_EXTERNAL_STORAGE permission to write to the secondary external storage, except when writing to their package-specific directories or within the URI returned by firing the ACTION_OPEN_DOCUMENT_TREE intent.

However, device implementations SHOULD expose content from both storage paths transparently through Android's media scanner service and android.provider.MediaStore.

Regardless of the form of shared storage used, if the device implementation has a USB port with USB peripheral mode support, it MUST provide some mechanism to access the contents of shared storage from a host computer. Device implementations MAY use USB mass storage, but SHOULD use Media Transfer Protocol to satisfy this requirement. If the device implementation supports Media Transfer Protocol, it:

  • SHOULD be compatible with the reference Android MTP host, Android File Transfer .
  • SHOULD report a USB device class of 0x00.
  • SHOULD report a USB interface name of 'MTP'.

7.6.3. Adoptable Storage

Device implementations are STRONGLY RECOMMENDED to implement adoptable storage if the removable storage device port is in a long-term stable location, such as within the battery compartment or other protective cover.

Device implementations such as a television, MAY enable adoption through USB ports as the device is expected to be static and not mobile. But for other device implementations that are mobile in nature, it is STRONGLY RECOMMENDED to implement the adoptable storage in a long-term stable location, since accidentally disconnecting them can cause data loss/corruption.

7.7. USB

Device implementations SHOULD support USB peripheral mode and SHOULD support USB host mode.

7.7.1. USB peripheral mode

If a device implementation includes a USB port supporting peripheral mode:

  • The port MUST be connectable to a USB host that has a standard type-A or type-C USB port.
  • The port SHOULD use micro-B, micro-AB or Type-C USB form factor. Existing and new Android devices are STRONGLY RECOMMENDED to meet these requirements so they will be able to upgrade to the future platform releases.
  • The port SHOULD be located on the bottom of the device (according to natural orientation) or enable software screen rotation for all apps (including home screen), so that the display draws correctly when the device is oriented with the port at bottom. Existing and new Android devices are STRONGLY RECOMMENDED to meet these requirements so they will be able to upgrade to future platform releases.
  • It MUST allow a USB host connected with the Android device to access the contents of the shared storage volume using either USB mass storage or Media Transfer Protocol.
  • It SHOULD implement the Android Open Accessory (AOA) API and specification as documented in the Android SDK documentation, and if it is an Android Handheld device it MUST implement the AOA API. Device implementations implementing the AOA specification:
    • MUST declare support for the hardware feature android.hardware.usb.accessory .
    • MUST implement the USB audio class as documented in the Android SDK documentation.
    • The USB mass storage class MUST include the string "android" at the end of the interface description iInterface string of the USB mass storage
  • It SHOULD implement support to draw 1.5 A current during HS chirp and traffic as specified in the USB Battery Charging specification, revision 1.2 . Existing and new Android devices are STRONGLY RECOMMENDED to meet these requirements so they will be able to upgrade to the future platform releases.
  • Type-C devices MUST detect 1.5A and 3.0A chargers per the Type-C resistor standard and it must detect changes in the advertisement.
  • Type-C devices also supporting USB host mode are STRONGLY RECOMMENDED to support Power Delivery for data and power role swapping.
  • Type-C devices SHOULD support Power Delivery for high-voltage charging and support for Alternate Modes such as display out.
  • The value of iSerialNumber in USB standard device descriptor MUST be equal to the value of android.os.Build.SERIAL.
  • Type-C devices are STRONGLY RECOMMENDED to not support proprietary charging methods that modify Vbus voltage beyond default levels, or alter sink/source roles as such may result in interoperability issues with the chargers or devices that support the standard USB Power Delivery methods. While this is called out as "STRONGLY RECOMMENDED", in future Android versions we might REQUIRE all type-C devices to support full interoperability with standard type-C chargers.

7.7.2. USB host mode

If a device implementation includes a USB port supporting host mode, it:

  • SHOULD use a type-C USB port, if the device implementation supports USB 3.1.
  • MAY use a non-standard port form factor, but if so MUST ship with a cable or cables adapting the port to a standard type-A or type-C USB port.
  • MAY use a micro-AB USB port, but if so SHOULD ship with a cable or cables adapting the port to a standard type-A or type-C USB port.
  • is STRONGLY RECOMMENDED to implement the USB audio class as documented in the Android SDK documentation.
  • MUST implement the Android USB host API as documented in the Android SDK, and MUST declare support for the hardware feature android.hardware.usb.host .
  • SHOULD support device charging while in host mode; advertising a source current of at least 1.5A as specified in the Termination Parameters section of the [USB Type-C Cable and Connector Specification Revision 1.2] (http://www.usb.org/developers/docs/usb_31_021517.zip) for USB Type-C connectors or using Charging Downstream Port(CDP) output current range as specified in the USB Battery Charging specifications, revision 1.2 for Micro-AB connectors.
  • USB Type-C devices are STRONGLY RECOMMENDED to support DisplayPort, SHOULD support USB SuperSpeed Data Rates, and are STRONGLY RECOMMENDED to support Power Delivery for data and power role swapping.
  • Devices with any type-A or type-AB ports MUST NOT ship with an adapter converting from this port to a type-C receptacle.
  • MUST recognize any remotely connected MTP (Media Transfer Protocol) devices and make their contents accessible through the ACTION_GET_CONTENT , ACTION_OPEN_DOCUMENT , and ACTION_CREATE_DOCUMENT intents, if the Storage Access Framework (SAF) is supported.
  • MUST, if using a Type-C USB port and including support for peripheral mode, implement Dual Role Port functionality as defined by the USB Type-C specification (section 4.5.1.3.3).
  • SHOULD, if the Dual Role Port functionality is supported, implement the Try.* model that is most appropriate for the device form factor. For example a handheld device SHOULD implement the Try.SNK model.

7.8. Audio

7.8.1. Micrófono

Android Handheld, Watch, and Automotive implementations MUST include a microphone.

Device implementations MAY omit a microphone. However, if a device implementation omits a microphone, it MUST NOT report the android.hardware.microphone feature constant, and MUST implement the audio recording API at least as no-ops, per section 7 . Conversely, device implementations that do possess a microphone:

  • MUST report the android.hardware.microphone feature constant.
  • MUST meet the audio recording requirements in section 5.4 .
  • MUST meet the audio latency requirements in section 5.6 .
  • STRONGLY RECOMMENDED to support near-ultrasound recording as described in section 7.8.3 .

7.8.2. Audio Output

Android Watch devices MAY include an audio output.

Device implementations including a speaker or with an audio/multimedia output port for an audio output peripheral as a headset or an external speaker:

  • MUST report the android.hardware.audio.output feature constant.
  • MUST meet the audio playback requirements in section 5.5 .
  • MUST meet the audio latency requirements in section 5.6 .
  • STRONGLY RECOMMENDED to support near-ultrasound playback as described in section 7.8.3 .

Conversely, if a device implementation does not include a speaker or audio output port, it MUST NOT report the android.hardware.audio output feature, and MUST implement the Audio Output related APIs as no-ops at least.

Android Watch device implementation MAY but SHOULD NOT have audio output, but other types of Android device implementations MUST have an audio output and declare android.hardware.audio.output.

7.8.2.1. Analog Audio Ports

In order to be compatible with the headsets and other audio accessories using the 3.5mm audio plug across the Android ecosystem, if a device implementation includes one or more analog audio ports, at least one of the audio port(s) SHOULD be a 4 conductor 3.5mm audio jack. If a device implementation has a 4 conductor 3.5mm audio jack, it:

  • MUST support audio playback to stereo headphones and stereo headsets with a microphone, and SHOULD support audio recording from stereo headsets with a microphone.
  • MUST support TRRS audio plugs with the CTIA pin-out order, and SHOULD support audio plugs with the OMTP pin-out order.
  • MUST support the detection of microphone on the plugged in audio accessory, if the device implementation supports a microphone, and broadcast the android.intent.action.HEADSET_PLUG with the extra value microphone set as 1.
  • MUST support the detection and mapping to the keycodes for the following 3 ranges of equivalent impedance between the microphone and ground conductors on the audio plug:
    • 70 ohm or less : KEYCODE_HEADSETHOOK
    • 210-290 Ohm : KEYCODE_VOLUME_UP
    • 360-680 Ohm : KEYCODE_VOLUME_DOWN
  • STRONGLY RECOMMENDED to detect and map to the keycode for the following range of equivalent impedance between the microphone and ground conductors on the audio plug:
    • 110-180 Ohm: KEYCODE_VOICE_ASSIST
  • MUST trigger ACTION_HEADSET_PLUG upon a plug insert, but only after all contacts on plug are touching their relevant segments on the jack.
  • MUST be capable of driving at least 150mV ± 10% of output voltage on a 32 Ohm speaker impedance.
  • MUST have a microphone bias voltage between 1.8V ~ 2.9V.

7.8.3. Near-Ultrasound

Near-Ultrasound audio is the 18.5 kHz to 20 kHz band. Device implementations MUST correctly report the support of near-ultrasound audio capability via the AudioManager.getProperty API as follows:

  • If PROPERTY_SUPPORT_MIC_NEAR_ULTRASOUND is "true", then the following requirements must be met by the VOICE_RECOGNITION and UNPROCESSED audio sources:
    • The microphone's mean power response in the 18.5 kHz to 20 kHz band MUST be no more than 15 dB below the response at 2 kHz.
    • The microphone's unweighted signal to noise ratio over 18.5 kHz to 20 kHz for a 19 kHz tone at -26 dBFS MUST be no lower than 50 dB.
  • If PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND is "true", then the speaker's mean response in 18.5 kHz - 20 kHz MUST be no lower than 40 dB below the response at 2 kHz.

7.9. Virtual Reality

Android includes APIs and facilities to build "Virtual Reality" (VR) applications including high quality mobile VR experiences. Device implementations MUST properly implement these APIs and behaviors, as detailed in this section.

7.9.1. Virtual Reality Mode

Android handheld device implementations that support a mode for VR applications that handles stereoscopic rendering of notifications and disable monocular system UI components while a VR application has user focus MUST declare android.software.vr.mode feature. Devices declaring this feature MUST include an application implementing android.service.vr.VrListenerService that can be enabled by VR applications via android.app.Activity#setVrModeEnabled .

7.9.2. Virtual Reality High Performance

Android handheld device implementations MUST identify the support of high performance virtual reality for longer user periods through the android.hardware.vr.high_performance feature flag and meet the following requirements.

  • Device implementations MUST have at least 2 physical cores.
  • Device implementations MUST declare android.software.vr.mode feature.
  • Device implementations MAY provide an exclusive core to the foreground application and MAY support the Process.getExclusiveCores API to return the numbers of the cpu cores that are exclusive to the top foreground application. If exclusive core is supported then the core MUST not allow any other userspace processes to run on it (except device drivers used by the application), but MAY allow some kernel processes to run as necessary.
  • Device implementations MUST support sustained performance mode.
  • Device implementations MUST support OpenGL ES 3.2.
  • Device implementations MUST support Vulkan Hardware Level 0 and SHOULD support Vulkan Hardware Level 1.
  • Device implementations MUST implement EGL_KHR_mutable_render_buffer and EGL_ANDROID_front_buffer_auto_refresh, EGL_ANDROID_create_native_client_buffer, EGL_KHR_fence_sync and EGL_KHR_wait_sync so that they may be used for Shared Buffer Mode, and expose the extensions in the list of available EGL extensions.
  • The GPU and display MUST be able to synchronize access to the shared front buffer such that alternating-eye rendering of VR content at 60fps with two render contexts will be displayed with no visible tearing artifacts.
  • Device implementations MUST implement EGL_IMG_context_priority, and expose the extension in the list of available EGL extensions.
  • Device implementations MUST implement GL_EXT_multisampled_render_to_texture, GL_OVR_multiview, GL_OVR_multiview2 and GL_OVR_multiview_multisampled_render_to_texture, and expose the extensions in the list of available GL extensions.
  • Device implementations MUST implement EGL_EXT_protected_content and GL_EXT_protected_textures so that it may be used for Secure Texture Video Playback, and expose the extensions in the list of available EGL and GL extensions.
  • Device implementations MUST support H.264 decoding at least 3840x2160@30fps-40Mbps (equivalent to 4 instances of 1920x1080@30fps-10Mbps or 2 instances of 1920x1080@60fps-20Mbps).
  • Device implementations MUST support HEVC and VP9, MUST be capable to decode at least 1920x1080@30fps-10Mbps and SHOULD be capable to decode 3840x2160@30fps-20Mbps (equivalent to 4 instances of 1920x1080@30fps-5Mbps).
  • The device implementations are STRONGLY RECOMMENDED to support android.hardware.sensor.hifi_sensors feature and MUST meet the gyroscope, accelerometer, and magnetometer related requirements for android.hardware.hifi_sensors.
  • Device implementations MUST support HardwarePropertiesManager.getDeviceTemperatures API and return accurate values for skin temperature.
  • The device implementation MUST have an embedded screen, and its resolution MUST be at least be FullHD(1080p) and STRONGLY RECOMMENDED TO BE be QuadHD (1440p) or higher.
  • The display MUST measure between 4.7" and 6" diagonal.
  • The display MUST update at least 60 Hz while in VR Mode.
  • The display latency on Gray-to-Gray, White-to-Black, and Black-to-White switching time MUST be ≤ 3 ms.
  • The display MUST support a low-persistence mode with ≤5 ms persistence,persistence being defined as the amount of time for which a pixel is emitting light.
  • Device implementations MUST support Bluetooth 4.2 and Bluetooth LE Data Length Extension section 7.4.3 .

8. Performance and Power

Some minimum performance and power criteria are critical to the user experience and impact the baseline assumptions developers would have when developing an app. Android Watch devices SHOULD and other type of device implementations MUST meet the following criteria.

8.1. User Experience Consistency

Device implementations MUST provide a smooth user interface by ensuring a consistent frame rate and response times for applications and games. Device implementations MUST meet the following requirements:

  • Consistent frame latency . Inconsistent frame latency or a delay to render frames MUST NOT happen more often than 5 frames in a second, and SHOULD be below 1 frames in a second.
  • User interface latency . Device implementations MUST ensure low latency user experience by scrolling a list of 10K list entries as defined by the Android Compatibility Test Suite (CTS) in less than 36 secs.
  • Task switching . When multiple applications have been launched, re-launching an already-running application after it has been launched MUST take less than 1 second.

8.2. File I/O Access Performance

Device implementations MUST ensure internal storage file access performance consistency for read and write operations.

  • Sequential write . Device implementations MUST ensure a sequential write performance of at least 5MB/s for a 256MB file using 10MB write buffer.
  • Random write . Device implementations MUST ensure a random write performance of at least 0.5MB/s for a 256MB file using 4KB write buffer.
  • Sequential read . Device implementations MUST ensure a sequential read performance of at least 15MB/s for a 256MB file using 10MB write buffer.
  • Random read . Device implementations MUST ensure a random read performance of at least 3.5MB/s for a 256MB file using 4KB write buffer.

8.3. Power-Saving Modes

Android 6.0 introduced App Standby and Doze power-saving modes to optimize battery usage. All Apps exempted from these modes MUST be made visible to the end user. Further, the triggering, maintenance, wakeup algorithms and the use of global system settings of these power-saving modes MUST not deviate from the Android Open Source Project.

In addition to the power-saving modes, Android device implementations MAY implement any or all of the 4 sleeping power states as defined by the Advanced Configuration and Power Interface (ACPI), but if it implements S3 and S4 power states, it can only enter these states when closing a lid that is physically part of the device.

8.4. Power Consumption Accounting

A more accurate accounting and reporting of the power consumption provides the app developer both the incentives and the tools to optimize the power usage pattern of the application. Therefore, device implementations:

  • MUST be able to track hardware component power usage and attribute that power usage to specific applications. Specifically, implementations:
    • MUST provide a per-component power profile that defines the current consumption value for each hardware component and the approximate battery drain caused by the components over time as documented in the Android Open Source Project site.
    • MUST report all power consumption values in milliampere hours (mAh).
    • SHOULD be attributed to the hardware component itself if unable to attribute hardware component power usage to an application.
    • MUST report CPU power consumption per each process's UID. The Android Open Source Project meets the requirement through the uid_cputime kernel module implementation.
  • MUST make this power usage available via the adb shell dumpsys batterystats shell command to the app developer.
  • MUST honor the android.intent.action.POWER_USAGE_SUMMARY intent and display a settings menu that shows this power usage.

8.5. Consistent Performance

Performance can fluctuate dramatically for high-performance long-running apps, either because of the other apps running in the background or the CPU throttling due to temperature limits. Android includes programmatic interfaces so that when the device is capable, the top foreground application can request that the system optimize the allocation of the resources to address such fluctuations.

Device implementations SHOULD support Sustained Performance Mode which can provide the top foreground application a consistent level of performance for a prolonged amount of time when requested through the Window.setSustainedPerformanceMode() API method. A Device implementation MUST report the support of Sustained Performance Mode accurately through the PowerManager.isSustainedPerformanceModeSupported() API method.

Device implementations with two or more CPU cores SHOULD provide at least one exclusive core that can be reserved by the top foreground application. If provided, implementations MUST meet the following requirements:

  • Implementations MUST report through the Process.getExclusiveCores() API method the id numbers of the exclusive cores that can be reserved by the top foreground application.
  • Device implementations MUST not allow any user space processes except the device drivers used by the application to run on the exclusive cores, but MAY allow some kernel processes to run as necessary.

If a device implementation does not support an exclusive core, it MUST return an empty list through the Process.getExclusiveCores() API method.

9. Security Model Compatibility

Device implementations MUST implement a security model consistent with the Android platform security model as defined in Security and Permissions reference document in the APIs in the Android developer documentation. Device implementations MUST support installation of self-signed applications without requiring any additional permissions/certificates from any third parties/authorities. Specifically, compatible devices MUST support the security mechanisms described in the follow subsections.

9.1. permisos

Device implementations MUST support the Android permissions model as defined in the Android developer documentation. Specifically, implementations MUST enforce each permission defined as described in the SDK documentation; no permissions may be omitted, altered, or ignored. Implementations MAY add additional permissions, provided the new permission ID strings are not in the android.* namespace.

Permissions with a protectionLevel of 'PROTECTION_FLAG_PRIVILEGED' MUST only be granted to apps preloaded in the whitelisted privileged path(s) of the system image, such as the system/priv-app path in the AOSP implementation.

Permissions with a protection level of dangerous are runtime permissions. Applications with targetSdkVersion > 22 request them at runtime. Implementaciones de dispositivos:

  • MUST show a dedicated interface for the user to decide whether to grant the requested runtime permissions and also provide an interface for the user to manage runtime permissions.
  • MUST have one and only one implementation of both user interfaces.
  • MUST NOT grant any runtime permissions to preinstalled apps unless:
    • the user's consent can be obtained before the application uses it
    • the runtime permissions are associated with an intent pattern for which the preinstalled application is set as the default handler

9.2. UID and Process Isolation

Device implementations MUST support the Android application sandbox model, in which each application runs as a unique Unixstyle UID and in a separate process. Device implementations MUST support running multiple applications as the same Linux user ID, provided that the applications are properly signed and constructed, as defined in the Security and Permissions reference .

9.3. Filesystem Permissions

Device implementations MUST support the Android file access permissions model as defined in the Security and Permissions reference .

9.4. Alternate Execution Environments

Device implementations MAY include runtime environments that execute applications using some other software or technology than the Dalvik Executable Format or native code. However, such alternate execution environments MUST NOT compromise the Android security model or the security of installed Android applications, as described in this section.

Alternate runtimes MUST themselves be Android applications, and abide by the standard Android security model, as described elsewhere in section 9 .

Alternate runtimes MUST NOT be granted access to resources protected by permissions not requested in the runtime's AndroidManifest.xml file via the <uses-permission> mechanism.

Alternate runtimes MUST NOT permit applications to make use of features protected by Android permissions restricted to system applications.

Alternate runtimes MUST abide by the Android sandbox model. Specifically, alternate runtimes:

  • SHOULD install apps via the PackageManager into separate Android sandboxes (Linux user IDs, etc.).
  • MAY provide a single Android sandbox shared by all applications using the alternate runtime.
  • Installed applications using an alternate runtime MUST NOT reuse the sandbox of any other app installed on the device, except through the standard Android mechanisms of shared user ID and signing certificate.
  • MUST NOT launch with, grant, or be granted access to the sandboxes corresponding to other Android applications.
  • MUST NOT be launched with, be granted, or grant to other applications any privileges of the superuser (root), or of any other user ID.

The .apk files of alternate runtimes MAY be included in the system image of a device implementation, but MUST be signed with a key distinct from the key used to sign other applications included with the device implementation.

When installing applications, alternate runtimes MUST obtain user consent for the Android permissions used by the application. If an application needs to make use of a device resource for which there is a corresponding Android permission (such as Camera, GPS, etc.), the alternate runtime MUST inform the user that the application will be able to access that resource. If the runtime environment does not record application capabilities in this manner, the runtime environment MUST list all permissions held by the runtime itself when installing any application using that runtime.

9.5. Multi-User Support

This feature is optional for all device types.

Android includes support for multiple users and provides support for full user isolation. Device implementations MAY enable multiple users, but when enabled MUST meet the following requirements related to multi-user support :

  • Android Automotive device implementations with multi-user support enabled MUST include a guest account that allows all functions provided by the vehicle system without requiring a user to log in.
  • Device implementations that do not declare the android.hardware.telephony feature flag MUST support restricted profiles, a feature that allows device owners to manage additional users and their capabilities on the device. With restricted profiles, device owners can quickly set up separate environments for additional users to work in, with the ability to manage finer-grained restrictions in the apps that are available in those environments.
  • Conversely device implementations that declare the android.hardware.telephony feature flag MUST NOT support restricted profiles but MUST align with the AOSP implementation of controls to enable /disable other users from accessing the voice calls and SMS.
  • Device implementations MUST, for each user, implement a security model consistent with the Android platform security model as defined in Security and Permissions reference document in the APIs.
  • Each user instance on an Android device MUST have separate and isolated external storage directories. Device implementations MAY store multiple users' data on the same volume or filesystem. However, the device implementation MUST ensure that applications owned by and running on behalf a given user cannot list, read, or write to data owned by any other user. Note that removable media, such as SD card slots, can allow one user to access another's data by means of a host PC. For this reason, device implementations that use removable media for the external storage APIs MUST encrypt the contents of the SD card if multiuser is enabled using a key stored only on non-removable media accessible only to the system. As this will make the media unreadable by a host PC, device implementations will be required to switch to MTP or a similar system to provide host PCs with access to the current user's data. Accordingly, device implementations MAY but SHOULD NOT enable multi-user if they use removable media for primary external storage.

9.6. Premium SMS Warning

Android includes support for warning users of any outgoing premium SMS message . Premium SMS messages are text messages sent to a service registered with a carrier that may incur a charge to the user. Device implementations that declare support for android.hardware.telephony MUST warn users before sending a SMS message to numbers identified by regular expressions defined in /data/misc/sms/codes.xml file in the device. The upstream Android Open Source Project provides an implementation that satisfies this requirement.

9.7. Kernel Security Features

The Android Sandbox includes features that use the Security-Enhanced Linux (SELinux) mandatory access control (MAC) system, seccomp sandboxing, and other security features in the Linux kernel. SELinux or any other security features implemented below the Android framework:

  • MUST maintain compatibility with existing applications.
  • MUST NOT have a visible user interface when a security violation is detected and successfully blocked, but MAY have a visible user interface when an unblocked security violation occurs resulting in a successful exploit.
  • SHOULD NOT be user or developer configurable.

If any API for configuration of policy is exposed to an application that can affect another application (such as a Device Administration API), the API MUST NOT allow configurations that break compatibility.

Devices MUST implement SELinux or, if using a kernel other than Linux, an equivalent mandatory access control system. Devices MUST also meet the following requirements, which are satisfied by the reference implementation in the upstream Android Open Source Project.

Implementaciones de dispositivos:

  • MUST set SELinux to global enforcing mode.
  • MUST configure all domains in enforcing mode. No permissive mode domains are allowed, including domains specific to a device/vendor.
  • MUST NOT modify, omit, or replace the neverallow rules present within the system/sepolicy folder provided in the upstream Android Open Source Project (AOSP) and the policy MUST compile with all neverallow rules present, for both AOSP SELinux domains as well as device/vendor specific domains.
  • MUST split the media framework into multiple processes so that it is possible to more narrowly grant access for each process as described in the Android Open Source Project site.

Device implementations SHOULD retain the default SELinux policy provided in the system/sepolicy folder of the upstream Android Open Source Project and only further add to this policy for their own device-specific configuration. Device implementations MUST be compatible with the upstream Android Open Source Project.

Devices MUST implement a kernel application sandboxing mechanism which allows filtering of system calls using a configurable policy from multithreaded programs. The upstream Android Open Source Project meets this requirement through enabling the seccomp-BPF with threadgroup synchronization (TSYNC) as described in the Kernel Configuration section of source.android.com .

9.8. Privacy

If the device implements functionality in the system that captures the contents displayed on the screen and/or records the audio stream played on the device, it MUST continuously notify the user whenever this functionality is enabled and actively capturing/recording.

If a device implementation has a mechanism that routes network data traffic through a proxy server or VPN gateway by default (for example, preloading a VPN service with android.permission.CONTROL_VPN granted), the device implementation MUST ask for the user's consent before enabling that mechanism, unless that VPN is enabled by the Device Policy Controller via the DevicePolicyManager.setAlwaysOnVpnPackage() , in which case the user does not need to provide a separate consent, but MUST only be notified.

Device implementations MUST ship with an empty user-added Certificate Authority (CA) store, and MUST preinstall the same root certificates for the system-trusted CA store as provided in the upstream Android Open Source Project.

When devices are routed through a VPN, or a user root CA is installed, the implementation MUST display a warning indicating the network traffic may be monitored to the user.

If a device implementation has a USB port with USB peripheral mode support, it MUST present a user interface asking for the user's consent before allowing access to the contents of the shared storage over the USB port.

9.9. Data Storage Encryption

Optional for Android device implementations without a secure lock screen.

If the device implementation supports a secure lock screen as described in section 9.11.1, then the device MUST support data storage encryption of the application private data (/data partition), as well as the application shared storage partition (/sdcard partition) if it is a permanent, non-removable part of the device.

For device implementations supporting data storage encryption and with Advanced Encryption Standard (AES) crypto performance above 50MiB/sec, the data storage encryption MUST be enabled by default at the time the user has completed the out-of-box setup experience. If a device implementation is already launched on an earlier Android version with encryption disabled by default, such a device cannot meet the requirement through a system software update and thus MAY be exempted.

Device implementations SHOULD meet the above data storage encryption requirement via implementing File Based Encryption (FBE).

9.9.1. Direct Boot

All devices MUST implement the Direct Boot mode APIs even if they do not support Storage Encryption. In particular, the LOCKED_BOOT_COMPLETED and ACTION_USER_UNLOCKED Intents must still be broadcast to signal Direct Boot aware applications that Device Encrypted (DE) and Credential Encrypted (CE) storage locations are available for user.

9.9.2. File Based Encryption

Device implementations supporting FBE:

  • MUST boot up without challenging the user for credentials and allow Direct Boot aware apps to access to the Device Encrypted (DE) storage after the LOCKED_BOOT_COMPLETED message is broadcasted.
  • MUST only allow access to Credential Encrypted (CE) storage after the user has unlocked the device by supplying their credentials (eg. passcode, pin, pattern or fingerprint) and the ACTION_USER_UNLOCKED message is broadcasted. Device implementations MUST NOT offer any method to unlock the CE protected storage without the user supplied credentials.
  • MUST support Verified Boot and ensure that DE keys are cryptographically bound to the device's hardware root of trust.
  • MUST support encrypting file contents using AES with a key length of 256-bits in XTS mode.
  • MUST support encrypting file name using AES with a key length of 256-bits in CBC-CTS mode.
  • MAY support alternative ciphers, key lengths and modes for file content and file name encryption, but MUST use the mandatorily supported ciphers, key lengths and modes by default.
  • SHOULD make preloaded essential apps (eg Alarm, Phone, Messenger) Direct Boot aware.

The keys protecting CE and DE storage areas:

  • MUST be cryptographically bound to a hardware-backed Keystore. CE keys must be bound to a user's lock screen credentials. If the user has specified no lock screen credentials then the CE keys MUST be bound to a default passcode.
  • MUST be unique and distinct, in other words no user's CE or DE key may match any other user's CE or DE keys.

The upstream Android Open Source project provides a preferred implementation of this feature based on the Linux kernel ext4 encryption feature.

9.9.3. Full Disk Encryption

Device implementations supporting full disk encryption (FDE). MUST use AES with a key of 128-bits (or greater) and a mode designed for storage (for example, AES-XTS, AES-CBC-ESSIV). The encryption key MUST NOT be written to storage at any time without being encrypted. The user MUST be provided with the possibility to AES encrypt the encryption key, except when it is in active use, with the lock screen credentials stretched using a slow stretching algorithm (eg PBKDF2 or scrypt). If the user has not specified a lock screen credentials or has disabled use of the passcode for encryption, the system SHOULD use a default passcode to wrap the encryption key. If the device provides a hardware-backed keystore, the password stretching algorithm MUST be cryptographically bound to that keystore. The encryption key MUST NOT be sent off the device (even when wrapped with the user passcode and/or hardware bound key). The upstream Android Open Source project provides a preferred implementation of this feature based on the Linux kernel feature dm-crypt.

9.10. Device Integrity

The following requirements ensures there is transparancy to the status of the device integrity.

Device implementations MUST correctly report through the System API method PersistentDataBlockManager.getFlashLockState() whether their bootloader state permits flashing of the system image. The FLASH_LOCK_UNKNOWN state is reserved for device implementations upgrading from an earlier version of Android where this new system API method did not exist.

Verified boot is a feature that guarantees the integrity of the device software. If a device implementation supports the feature, it MUST:

  • Declare the platform feature flag android.software.verified_boot.
  • Perform verification on every boot sequence.
  • Start verification from an immutable hardware key that is the root of trust and go all the way up to the system partition.
  • Implement each stage of verification to check the integrity and authenticity of all the bytes in the next stage before executing the code in the next stage.
  • Use verification algorithms as strong as current recommendations from NIST for hashing algorithms (SHA-256) and public key sizes (RSA-2048).
  • MUST NOT allow boot to complete when system verification fails, unless the user consents to attempt booting anyway, in which case the data from any non-verified storage blocks MUST not be used.
  • MUST NOT allow verified partitions on the device to be modified unless the user has explicitly unlocked the boot loader.

The upstream Android Open Source Project provides a preferred implementation of this feature based on the Linux kernel feature dm-verity.

Starting from Android 6.0, device implementations with Advanced Encryption Standard (AES) crypto performance above 50 MiB/seconds MUST support verified boot for device integrity.

If a device implementation is already launched without supporting verified boot on an earlier version of Android, such a device can not add support for this feature with a system software update and thus are exempted from the requirement.

9.11. Keys and Credentials

The Android Keystore System allows app developers to store cryptographic keys in a container and use them in cryptographic operations through the KeyChain API or the Keystore API .

All Android device implementations MUST meet the following requirements:

  • SHOULD not limit the number of keys that can be generated, and MUST at least allow more than 8,192 keys to be imported.
  • The lock screen authentication MUST rate limit attempts and MUST have an exponential backoff algorithm. Beyond 150 failed attempts, the delay MUST be at least 24 hours per attempt.
  • When the device implementation supports a secure lock screen it MUST back up the keystore implementation with secure hardware and meet following requirements:
    • MUST have implementations of RSA, AES, ECDSA and HMAC cryptographic algorithms and MD5, SHA1, and SHA-2 family hash functions to properly support the Android Keystore system's supported algorithms in an area that is securely isolated from the code running on the kernel and above. Secure isolation MUST block all potential mechanisms by which kernel or userspace code might access the internal state of the isolated environment, including DMA. The upstream Android Open Source Project (AOSP) meets this requirement by using the Trusty implementation, but another ARM TrustZone-based solution or a third-party reviewed secure implementation of a proper hypervisor-based isolation are alternative options.
    • MUST perform the lock screen authentication in the isolated execution environment and only when successful, allow the authentication-bound keys to be used. The upstream Android Open Source Project provides the Gatekeeper Hardware Abstraction Layer (HAL) and Trusty, which can be used to satisfy this requirement.

Note that if a device implementation is already launched on an earlier Android version, such a device is exempted from the requirement to have a hardware-backed keystore, unless it declares the android.hardware.fingerprint feature which requires a hardware-backed keystore.

9.11.1. Secure Lock Screen

Device implementations MAY add or modify the authentication methods to unlock the lock screen, but MUST still meet the following requirements:

  • The authentication method, if based on a known secret, MUST NOT be treated as a secure lock screen unless it meets all following requirements:
    • The entropy of the shortest allowed length of inputs MUST be greater than 10 bits.
    • The maximum entropy of all possible inputs MUST be greater than 18 bits.
    • MUST not replace any of the existing authentication methods (PIN, pattern, password) implemented and provided in AOSP.
    • MUST be disabled when the Device Policy Controller (DPC) application has set the password quality policy via the DevicePolicyManager.setPasswordQuality() method with a more restrictive quality constant than PASSWORD_QUALITY_SOMETHING .
  • The authenticaion method, if based on a physical token or the location, MUST NOT be treated as a secure lock screen unless it meets all following requirements:
  • The authentication method, if based on biometrics, MUST NOT be treated as a secure lock screen unless it meets all following requirements:
    • It MUST have a fall-back mechanism to use one of the primary authentication methods which is based on a known secret and meets the requirements to be treated as a secure lock screen.
    • It MUST be disabled and only allow the primary authentication to unlock the screen when the Device Policy Controller (DPC) application has set the keguard feature policy by calling the method DevicePolicyManager.setKeyguardDisabledFeatures(KEYGUARD_DISABLE_FINGERPRINT) .
    • It MUST have a false acceptance rate that is equal or stronger than what is required for a fingerprint sensor as described in section 7.3.10, or otherwise MUST be disabled and only allow the primary authentication to unlock the screen when the Device Policy Controller (DPC) application has set the password quality policy via the DevicePolicyManager.setPasswordQuality() method with a more restrictive quality constant than PASSWORD_QUALITY_BIOMETRIC_WEAK .
  • If the authentication method can not be treated as a secure lock screen, it:
  • If the authentication method is based on a physical token, the location, or biometrics that has higher false acceptance rate than what is required for fingerprint sensors as described in section 7.3.10, then it:

9.12. Data Deletion

Devices MUST provide users with a mechanism to perform a "Factory Data Reset" that allows logical and physical deletion of all data except for the following:

  • The system image
  • Any operating system files required by the system image

All user-generated data MUST be deleted. This MUST satisfy relevant industry standards for data deletion such as NIST SP800-88. This MUST be used for the implementation of the wipeData() API (part of the Android Device Administration API) described in section 3.9 Device Administration .

Devices MAY provide a fast data wipe that conducts a logical data erase.

9.13. Safe Boot Mode

Android provides a mode enabling users to boot up into a mode where only preinstalled system apps are allowed to run and all third-party apps are disabled. This mode, known as "Safe Boot Mode", provides the user the capability to uninstall potentially harmful third-party apps.

Android device implementations are STRONGLY RECOMENDED to implement Safe Boot Mode and meet following requirements:

  • Device implementations SHOULD provide the user an option to enter Safe Boot Mode from the boot menu which is reachable through a workflow that is different from that of normal boot.

  • Device implementations MUST provide the user an option to enter Safe Boot Mode in such a way that is uninterruptible from third-party apps installed on the device, except for when the third party app is a Device Policy Controller and has set the UserManager.DISALLOW_SAFE_BOOT flag as true.

  • Device implementations MUST provide the user the capability to uninstall any third-party apps within Safe Mode.

9.14. Automotive Vehicle System Isolation

Android Automotive devices are expected to exchange data with critical vehicle subsystems, eg, by using the vehicle HAL to send and receive messages over vehicle networks such as CAN bus. Android Automotive device implementations MUST implement security features below the Android framework layers to prevent malicious or unintentional interaction between the Android framework or third-party apps and vehicle subsystems. These security features are as follows:

  • Gatekeeping messages from Android framework vehicle subsystems, eg, whitelisting permitted message types and message sources.
  • Watchdog against denial of service attacks from the Android framework or third-party apps. This guards against malicious software flooding the vehicle network with traffic, which may lead to malfunctioning vehicle subsystems.

10. Software Compatibility Testing

Device implementations MUST pass all tests described in this section.

However, note that no software test package is fully comprehensive. For this reason, device implementers are STRONGLY RECOMMENDED to make the minimum number of changes as possible to the reference and preferred implementation of Android available from the Android Open Source Project. This will minimize the risk of introducing bugs that create incompatibilities requiring rework and potential device updates.

10.1. Compatibility Test Suite

Device implementations MUST pass the Android Compatibility Test Suite (CTS) available from the Android Open Source Project, using the final shipping software on the device. Additionally, device implementers SHOULD use the reference implementation in the Android Open Source tree as much as possible, and MUST ensure compatibility in cases of ambiguity in CTS and for any reimplementations of parts of the reference source code.

The CTS is designed to be run on an actual device. Like any software, the CTS may itself contain bugs. The CTS will be versioned independently of this Compatibility Definition, and multiple revisions of the CTS may be released for Android 7.1. Device implementations MUST pass the latest CTS version available at the time the device software is completed.

10.2. CTS Verifier

Device implementations MUST correctly execute all applicable cases in the CTS Verifier. The CTS Verifier is included with the Compatibility Test Suite, and is intended to be run by a human operator to test functionality that cannot be tested by an automated system, such as correct functioning of a camera and sensors.

The CTS Verifier has tests for many kinds of hardware, including some hardware that is optional. Device implementations MUST pass all tests for hardware that they possess; for instance, if a device possesses an accelerometer, it MUST correctly execute the Accelerometer test case in the CTS Verifier. Test cases for features noted as optional by this Compatibility Definition Document MAY be skipped or omitted.

Every device and every build MUST correctly run the CTS Verifier, as noted above. However, since many builds are very similar, device implementers are not expected to explicitly run the CTS Verifier on builds that differ only in trivial ways. Specifically, device implementations that differ from an implementation that has passed the CTS Verifier only by the set of included locales, branding, etc. MAY omit the CTS Verifier test.

11. Updatable Software

Device implementations MUST include a mechanism to replace the entirety of the system software. The mechanism need not perform “live” upgrades—that is, a device restart MAY be required.

Any method can be used, provided that it can replace the entirety of the software preinstalled on the device. For instance, any of the following approaches will satisfy this requirement:

  • “Over-the-air (OTA)” downloads with offline update via reboot.
  • “Tethered” updates over USB from a host PC.
  • “Offline” updates via a reboot and update from a file on removable storage.

However, if the device implementation includes support for an unmetered data connection such as 802.11 or Bluetooth PAN (Personal Area Network) profile, it MUST support OTA downloads with offline update via reboot.

The update mechanism used MUST support updates without wiping user data. That is, the update mechanism MUST preserve application private data and application shared data. Note that the upstream Android software includes an update mechanism that satisfies this requirement.

For device implementations that are launching with Android 6.0 and later, the update mechanism SHOULD support verifying that the system image is binary identical to expected result following an OTA. The block-based OTA implementation in the upstream Android Open Source Project, added since Android 5.1, satisfies this requirement.

Also, device implementations SHOULD support A/B system updates . The AOSP implements this feature using the boot control HAL.

If an error is found in a device implementation after it has been released but within its reasonable product lifetime that is determined in consultation with the Android Compatibility Team to affect the compatibility of third-party applications, the device implementer MUST correct the error via a software update available that can be applied per the mechanism just described.

Android includes features that allow the Device Owner app (if present) to control the installation of system updates. To facilitate this, the system update subsystem for devices that report android.software.device_admin MUST implement the behavior described in the SystemUpdatePolicy class.

12. Document Changelog

For a summary of changes to the Compatibility Definition in this release:

For a summary of changes to individuals sections:

  1. Introduction
  2. Device Types
  3. Software
  4. Application Packaging
  5. Multimedia
  6. Developer Tools and Options
  7. Hardware Compatibility
  8. Performance and Power
  9. Security Model
  10. Software Compatibility Testing
  11. Updatable Software
  12. Document Changelog
  13. Contact Us

12.1. Changelog Viewing Tips

Changes are marked as follows:

  • CDD
    Substantive changes to the compatibility requirements.

  • Docs
    Cosmetic or build related changes.

For best viewing, append the pretty=full and no-merges URL parameters to your changelog URLs.

13. Contact Us

You can join the android-compatibility forum and ask for clarifications or bring up any issues that you think the document does not cover.