Definição de compatibilidade com Android 5.1

1. Introdução

Este documento enumera os requisitos que devem ser atendidos para que os dispositivos sejam compatíveis com o Android 5.1.

O uso de “DEVE”, “NÃO DEVE”, “NECESSÁRIO”, “DEVE”, “NÃO DEVE”, “DEVE”, “NÃO DEVE”, “RECOMENDADO”, “PODE” e “OPCIONAL” é de acordo com o IETF padrão definido na RFC2119 [ Recursos, 1 ].

Conforme usado neste documento, um “implementador de dispositivo” ou “implementador” é uma pessoa ou organização que desenvolve uma solução de hardware/software executando o Android 5.1. Uma “implementação de dispositivo” ou “implementação é a solução de hardware/software assim desenvolvida.

Para serem consideradas compatíveis com o Android 5.1, as implementações de dispositivos DEVEM atender aos requisitos apresentados nesta Definição de Compatibilidade, incluindo quaisquer documentos incorporados por referência.

Quando esta definição ou os testes de software descritos na seção 10 forem omissos, ambíguos ou incompletos, é responsabilidade do implementador do dispositivo garantir a compatibilidade com as implementações existentes.

Por esse motivo, o Android Open Source Project [ Resources, 2 ] é a implementação de referência e preferida do Android. Os implementadores de dispositivos são fortemente encorajados a basear suas implementações o máximo possível no código-fonte “upstream” disponível no Android Open Source Project. Embora alguns componentes possam hipoteticamente ser substituídos por implementações alternativas, essa prática é fortemente desencorajada, pois passar nos testes de software se tornará substancialmente mais difícil. É responsabilidade do implementador garantir total compatibilidade comportamental com a implementação padrão do Android, incluindo e além do Compatibility Test Suite. Finalmente, observe que certas substituições e modificações de componentes são explicitamente proibidas por este documento.

Muitos dos recursos listados na seção 14 são derivados direta ou indiretamente do Android SDK e serão funcionalmente idênticos às informações na documentação desse SDK. Para qualquer caso em que esta Definição de Compatibilidade ou o Conjunto de Testes de Compatibilidade discorde da documentação do SDK, a documentação do SDK é considerada oficial. Quaisquer detalhes técnicos fornecidos nas referências incluídas na seção 14 são considerados por inclusão como parte desta Definição de Compatibilidade.

2. Tipos de dispositivos

Embora o Android Open Source Project tenha sido usado na implementação de vários tipos de dispositivos e fatores de forma, muitos aspectos da arquitetura e dos requisitos de compatibilidade foram otimizados para dispositivos portáteis. A partir do Android 5.0, o Android Open Source Project visa abranger uma variedade maior de tipos de dispositivos, conforme descrito nesta seção.

Dispositivo portátil Android refere-se a uma implementação de dispositivo Android que normalmente é usada segurando-o na mão, como mp3 players, telefones e tablets. Implementações de dispositivos portáteis Android:

• DEVE ter uma tela sensível ao toque incorporada no dispositivo.
• DEVE ter uma fonte de alimentação que proporcione mobilidade, como uma bateria.

Dispositivo Android Television refere-se a uma implementação de dispositivo Android que é uma interface de entretenimento para consumir mídia digital, filmes, jogos, aplicativos e/ou TV ao vivo para usuários sentados a cerca de 3 metros de distância (uma interface de usuário “inclinada” ou “3 metros "). Dispositivos de televisão Android:

• DEVE ter uma tela incorporada OU incluir uma porta de saída de vídeo, como VGA, HDMI ou uma porta sem fio para exibição.
• DEVE declarar os recursos android.software.leanback e android.hardware.type.television [ Recursos, 3 ].

Dispositivo Android Watch refere-se a uma implementação de dispositivo Android destinada a ser usada no corpo, talvez no pulso, e:

• DEVE ter uma tela com o comprimento da diagonal física na faixa de 1,1 a 2,5 polegadas.
• DEVE declarar o recurso android.hardware.type.watch.
• DEVE suportar uiMode = UI_MODE_TYPE_WATCH [ Recursos, 4 ].

A implementação do Android Automotive refere-se a uma unidade principal de veículo executando o Android como um sistema operacional para parte ou todo o sistema e/ou funcionalidade de infoentretenimento. As implementações do Android Automotive DEVEM ser compatíveis com uiMode = UI_MODE_TYPE_CAR [ Recursos, 111 ].

Todas as implementações de dispositivos Android que não se encaixam em nenhum dos tipos de dispositivos acima ainda DEVEM atender a todos os requisitos deste documento para serem compatíveis com o Android 5.1, a menos que o requisito seja descrito explicitamente como aplicável apenas a um tipo de dispositivo Android específico acima.

2.1 Configurações do Dispositivo

Este é um resumo das principais diferenças na configuração de hardware por tipo de dispositivo. (As células vazias indicam um “MAY”). Nem todas as configurações são abordadas nesta tabela; consulte as seções de hardware relevantes para obter mais detalhes.

3. Software

3.1. Compatibilidade de API gerenciada

O ambiente de execução de bytecode gerenciado Dalvik é o principal veículo para aplicativos Android. A interface de programação de aplicativos (API) Android é o conjunto de interfaces da plataforma Android expostas a aplicativos executados no ambiente de tempo de execução gerenciado. As implementações de dispositivos DEVEM fornecer implementações completas, incluindo todos os comportamentos documentados, de qualquer API documentada exposta pelo Android SDK [ Recursos, 5 ] ou qualquer API decorada com o marcador “@SystemApi” no código-fonte do Android upstream.

As implementações de dispositivos NÃO DEVEM omitir nenhuma API gerenciada, alterar interfaces ou assinaturas de API, desviar-se do comportamento documentado ou incluir no-ops, exceto quando especificamente permitido por esta Definição de Compatibilidade.

Essa definição de compatibilidade permite que alguns tipos de hardware para os quais o Android inclui APIs sejam omitidos por implementações de dispositivos. Nesses casos, as APIs ainda DEVEM estar presentes e se comportar de maneira razoável. Consulte a seção 7 para obter os requisitos específicos para este cenário.

3.2. Compatibilidade de API suave

Além das APIs gerenciadas da seção 3.1 , o Android também inclui uma API “soft” somente de tempo de execução significativa, na forma de intenções, permissões e aspectos semelhantes de aplicativos Android que não podem ser aplicados no tempo de compilação do aplicativo.

3.2.1. Permissões

Os implementadores de dispositivos DEVEM dar suporte e aplicar todas as constantes de permissão conforme documentado pela página de referência de permissão [ Recursos, 6] . Observe que a seção 9 lista os requisitos adicionais relacionados ao modelo de segurança do Android.

3.2.2. Parâmetros de compilação

As APIs do Android incluem várias constantes na classe android.os.Build [ Resources, 7 ] que se destinam a descrever o dispositivo atual. Para fornecer valores consistentes e significativos em implementações de dispositivos, a tabela abaixo inclui restrições adicionais sobre os formatos desses valores aos quais as implementações de dispositivos DEVEM estar em conformidade.

3.2.3. Compatibilidade de intenção

As implementações de dispositivos DEVEM respeitar o sistema de intenção de acoplamento flexível do Android, conforme descrito nas seções abaixo. Por "honrado" entende-se que o implementador do dispositivo DEVE fornecer uma atividade ou serviço Android que especifique um filtro de intenção correspondente que se vincule e implemente o comportamento correto para cada padrão de intenção especificado.

3.2.3.1. Principais intenções do aplicativo

As intenções do Android permitem que os componentes do aplicativo solicitem a funcionalidade de outros componentes do Android. O projeto Android upstream inclui uma lista de aplicativos considerados aplicativos Android centrais, que implementam vários padrões de intenção para realizar ações comuns. Os principais aplicativos Android são:

• Relógio de mesa
• Navegador
• Calendário
• Contatos
• Galeria
• Pesquisa global
• Iniciador
• Música
• Definições

As implementações de dispositivos DEVEM incluir os aplicativos principais do Android conforme apropriado, mas DEVEM incluir um componente que implemente os mesmos padrões de intenção definidos por todos os componentes "públicos" de atividade ou serviço desses aplicativos principais do Android. Observe que os componentes Activity ou Service são considerados “públicos” quando o atributo android:exported está ausente ou tem o valor true.

3.2.3.2. Substituições de intenção

Como o Android é uma plataforma extensível, as implementações de dispositivos DEVEM permitir que cada padrão de intenção referenciado na seção 3.2.3.1 seja substituído por aplicativos de terceiros. A implementação de código aberto do Android upstream permite isso por padrão; os implementadores de dispositivos NÃO DEVEM anexar privilégios especiais ao uso desses padrões de intenção pelos aplicativos do sistema ou impedir que aplicativos de terceiros se vinculem e assumam o controle desses padrões. Essa proibição inclui especificamente, mas não se limita a, desabilitar a interface do usuário “Chooser” que permite ao usuário selecionar entre vários aplicativos que lidam com o mesmo padrão de intenção.

No entanto, as implementações de dispositivos PODEM fornecer atividades padrão para padrões de URI específicos (por exemplo, http://play.google.com) se a atividade padrão fornecer um filtro mais específico para o URI de dados. Por exemplo, um filtro de intent que especifica o URI de dados “http://www.android.com” é mais específico do que o filtro do navegador para “http://”. As implementações de dispositivos DEVEM fornecer uma interface de usuário para que os usuários modifiquem a atividade padrão para intents.

3.2.3.3. Namespaces de intent

As implementações de dispositivos NÃO DEVEM incluir nenhum componente Android que honre qualquer novo intent ou padrões de intent de transmissão usando uma ACTION, CATEGORY ou outra string de chave no namespace android.* ou com.android.*. Os implementadores de dispositivos NÃO DEVEM incluir componentes do Android que honrem qualquer nova intenção ou padrões de intenção de transmissão usando ACTION, CATEGORY ou outra string de chave em um espaço de pacote pertencente a outra organização. Os implementadores de dispositivos NÃO DEVEM alterar ou estender nenhum dos padrões de intenção usados ​​pelos aplicativos principais listados na seção 3.2.3.1 . As implementações de dispositivos PODEM incluir padrões de intenção usando namespaces clara e obviamente associados à sua própria organização. Essa proibição é análoga àquela especificada para classes de linguagem Java na seção 3.6 .

3.2.3.4. Intenções de transmissão

Aplicativos de terceiros dependem da plataforma para transmitir determinadas intenções para notificá-los sobre alterações no ambiente de hardware ou software. Dispositivos compatíveis com Android DEVEM transmitir as intenções de transmissão pública em resposta aos eventos apropriados do sistema. As intenções de transmissão são descritas na documentação do SDK.

3.2.3.5. Configurações padrão do aplicativo

O Android inclui configurações que fornecem aos usuários uma maneira fácil de selecionar seus aplicativos padrão, por exemplo, para a tela inicial ou SMS. Onde fizer sentido, as implementações de dispositivos DEVEM fornecer um menu de configurações semelhante e ser compatível com o padrão de filtro de intenção e os métodos de API descritos na documentação do SDK, conforme abaixo.

Implementações de dispositivos:

• DEVE respeitar a intenção android.settings.HOME_SETTINGS para mostrar um menu de configurações de aplicativo padrão para a tela inicial, se a implementação do dispositivo relatar android.software.home_screen [ Recursos, 10]
• DEVE fornecer um menu de configurações que chamará a intenção android.provider.Telephony.ACTION_CHANGE_DEFAULT para mostrar uma caixa de diálogo para alterar o aplicativo SMS padrão, se a implementação do dispositivo relatar android.hardware.telephony [ Recursos, 9 ]
• DEVE respeitar a intenção android.settings.NFC_PAYMENT_SETTINGS de mostrar um menu de configurações de aplicativo padrão para Tap and Pay, se a implementação do dispositivo relatar android.hardware.nfc.hce [ Recursos, 10]

3.3. Compatibilidade de API nativa

3.3.1. Interfaces Binárias de Aplicativos

O bytecode Dalvik gerenciado pode chamar o código nativo fornecido no arquivo .apk do aplicativo como um arquivo .so ELF compilado para a arquitetura de hardware de dispositivo apropriada. Como o código nativo é altamente dependente da tecnologia de processador subjacente, o Android define várias interfaces binárias de aplicativos (ABIs) no Android NDK. As implementações de dispositivos DEVEM ser compatíveis com uma ou mais ABIs definidas e DEVEM implementar a compatibilidade com o Android NDK, conforme abaixo.

Se uma implementação de dispositivo incluir suporte para uma ABI do Android, ela:

• DEVE incluir suporte para código em execução no ambiente gerenciado para chamar o código nativo, usando a semântica padrão da Java Native Interface (JNI)
• DEVE ser compatível com a fonte (ou seja, compatível com cabeçalho) e compatível com binário (para a ABI) com cada biblioteca necessária na lista abaixo
• DEVE suportar a ABI de 32 bits equivalente se qualquer ABI de 64 bits for suportada
• DEVE relatar com precisão a Interface Binária de Aplicativo (ABI) nativa suportada pelo dispositivo, por meio dos parâmetros android.os.Build.SUPPORTED_ABIS, android.os.Build.SUPPORTED_32_BIT_ABIS e android.os.Build.SUPPORTED_64_BIT_ABIS, cada um com uma lista separada por vírgulas de ABIs ordenados do mais para o menos preferido
• DEVE relatar, por meio dos parâmetros acima, apenas as ABIs documentadas na versão mais recente do Android NDK, “NDK Programmer's Guide | ABI Management” no diretório docs/
• DEVE ser construído usando o código-fonte e os arquivos de cabeçalho disponíveis no projeto de código aberto Android upstream

As seguintes APIs de código nativo DEVEM estar disponíveis para aplicativos que incluem código nativo:

• libc (biblioteca C)
• libm (biblioteca matemática)
• Suporte mínimo para C++
• Interface JNI
• liblog (registro do Android)
• libz (compressão Zlib)
• libdl (ligador dinâmico)
• libGLESv1_CM.so (OpenGL ES 1.x)
• libGLESv2.so (OpenGL ES 2.0)
• libGLESv3.so (OpenGL ES 3.x)
• libEGL.so (gerenciamento de superfície OpenGL nativo)
• libjnigraphics.so
• libOpenSLES.so (suporte de áudio OpenSL ES 1.0.1)
• libOpenMAXAL.so (suporte a OpenMAX AL 1.0.1)
• libandroid.so (suporte nativo à atividade do Android)
• libmediandk.so (suporte a APIs de mídia nativa)
• Suporte para OpenGL, conforme descrito abaixo

Observe que versões futuras do Android NDK podem apresentar suporte para ABIs adicionais. Se uma implementação de dispositivo não for compatível com uma ABI predefinida existente, ela NÃO DEVE relatar suporte para nenhuma ABI.

Observe que as implementações de dispositivos DEVEM incluir libGLESv3.so e DEVEM symlink (link simbólico) para libGLESv2.so. por sua vez, DEVE exportar todos os símbolos de função OpenGL ES 3.1 e Android Extension Pack [ Recursos, 11 ] conforme definido na versão do NDK android-21. Embora todos os símbolos devam estar presentes, apenas as funções correspondentes para versões e extensões do OpenGL ES realmente suportadas pelo dispositivo devem ser totalmente implementadas.

A compatibilidade de código nativo é um desafio. Por esse motivo, os implementadores de dispositivos são fortemente encorajados a usar as implementações das bibliotecas listadas acima do projeto de código aberto Android do upstream.

3.3.2. Compatibilidade de código nativo ARM de 32 bits

A arquitetura ARMv8 descontinua várias operações de CPU, incluindo algumas operações usadas no código nativo existente. Em dispositivos ARM de 64 bits, as seguintes operações obsoletas DEVEM permanecer disponíveis para código ARM nativo de 32 bits, seja por meio de suporte de CPU nativo ou por emulação de software:

• Instruções SWP e SWPB
• Instrução SETEND
• Operações de barreira CP15ISB, CP15DSB e CP15DMB

As versões legadas do Android NDK usavam /proc/cpuinfo para descobrir recursos de CPU de código nativo ARM de 32 bits. Para compatibilidade com aplicativos criados usando este NDK, os dispositivos DEVEM incluir as seguintes linhas em /proc/cpuinfo quando forem lidos por aplicativos ARM de 32 bits:

• "Recursos: ", seguido por uma lista de todos os recursos opcionais da CPU ARMv7 suportados pelo dispositivo
• "Arquitetura da CPU: ", seguido por um número inteiro que descreve a arquitetura ARM mais alta com suporte do dispositivo (por exemplo, "8" para dispositivos ARMv8)

Esses requisitos se aplicam somente quando /proc/cpuinfo é lido por aplicativos ARM de 32 bits. Os dispositivos não devem alterar /proc/cpuinfo quando lidos por aplicativos ARM de 64 bits ou não ARM.

3.4. Compatibilidade da Web

3.4.1. Compatibilidade do WebView

O recurso da plataforma android.software.webview DEVE ser relatado em qualquer dispositivo que forneça uma implementação completa da API android.webkit.WebView e NÃO DEVE ser relatado em dispositivos sem uma implementação completa da API. A implementação do Android Open Source usa código do Chromium Project para implementar o android.webkit.WebView [ Resources, 12 ]. Como não é viável desenvolver um conjunto de testes abrangente para um sistema de renderização da Web, os implementadores de dispositivos DEVEM usar a compilação upstream específica do Chromium na implementação do WebView. Especificamente:

• As implementações do dispositivo android.webkit.WebView DEVEM ser baseadas na compilação do Chromium do Android Open Source Project para Android 5.1. Esta compilação inclui um conjunto específico de funcionalidades e correções de segurança para o WebView [ Recursos, 13 ].
• A string do agente do usuário relatada pelo WebView DEVE estar neste formato:

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

  • O valor da string $(VERSION) DEVE ser o mesmo que o valor de android.os.Build.VERSION.RELEASE.
  • A string $(WEBVIEW) PODE ser omitida, mas se incluída DEVE ser "; wv" para observar que esta é uma visualização da web
  • O valor da string $(MODEL) DEVE ser o mesmo que o valor de android.os.Build.MODEL.
  • O valor da string $(BUILD) DEVE ser igual ao valor de android.os.Build.ID.
  • O valor da string $(CHROMIUM_VER) DEVE ser a versão do Chromium no Android Open Source Project.
  • Implementações de dispositivos PODEM omitir Mobile na string do agente do usuário.

O componente WebView DEVE incluir suporte para tantos recursos HTML5 quanto possível e se ele suporta o recurso DEVE estar em conformidade com a especificação HTML5 [ Recursos, 14 ].

3.4.2. Compatibilidade do navegador

O navegador autônomo PODE ser baseado em uma tecnologia de navegador diferente do WebKit. No entanto, mesmo que um aplicativo de navegador alternativo seja usado, o componente android.webkit.WebView fornecido para aplicativos de terceiros DEVE ser baseado no WebKit, conforme descrito na seção 3.4.1 .

As implementações PODEM enviar uma string personalizada do agente do usuário no aplicativo do navegador autônomo.

O aplicativo de navegador autônomo (seja baseado no aplicativo de navegador WebKit upstream ou um substituto de terceiros) DEVE incluir suporte para o máximo de HTML5 [ Recursos, 14 ] possível. No mínimo, as implementações de dispositivos DEVEM oferecer suporte a cada uma dessas APIs associadas ao HTML5:

• cache do aplicativo/operação offline [ Recursos, 15 ]
• a tag <video> [ Recursos, 16 ]
• geolocalização [ Recursos, 17 ]

Além disso, as implementações de dispositivos DEVEM suportar a API de armazenamento na web HTML5/W3C [ Recursos, 18 ] e DEVEM suportar a API HTML5/W3C IndexedDB [ Recursos, 19 ]. Observe que, como os órgãos de padrões de desenvolvimento da Web estão em transição para favorecer o IndexedDB em vez do armazenamento na Web, espera-se que o IndexedDB se torne um componente obrigatório em uma versão futura do Android.

3.5. Compatibilidade Comportamental da API

Os comportamentos de cada um dos tipos de API (gerenciado, flexível, nativo e web) devem ser consistentes com a implementação preferencial do projeto de código aberto Android upstream [ Resources, 2 ]. Algumas áreas específicas de compatibilidade são:

• Os dispositivos NÃO DEVEM alterar o comportamento ou a semântica de uma intenção padrão.
• Os dispositivos NÃO DEVEM alterar o ciclo de vida ou a semântica do ciclo de vida de um tipo específico de componente do sistema (como Serviço, Atividade, ContentProvider, etc.).
• Os dispositivos NÃO DEVEM alterar a semântica de uma permissão padrão.

A lista acima não é completa. O Compatibility Test Suite (CTS) testa partes significativas da plataforma para compatibilidade comportamental, mas não todas. É responsabilidade do implementador garantir a compatibilidade comportamental com o Android Open Source Project. Por esse motivo, os implementadores de dispositivos DEVEM usar o código-fonte disponível por meio do Android Open Source Project sempre que possível, em vez de reimplementar partes significativas do sistema.

3.6. Namespaces de API

O Android segue as convenções de namespace de pacote e classe definidas pela linguagem de programação Java. Para garantir a compatibilidade com aplicativos de terceiros, os implementadores de dispositivos NÃO DEVEM fazer nenhuma modificação proibida (veja abaixo) nestes namespaces de pacotes:

• Java.*
• javax.*
• Sol.*
• android.*
• com.android.*

As modificações proibidas incluem :

• As implementações de dispositivos NÃO DEVEM modificar as APIs expostas publicamente na plataforma Android alterando qualquer método ou assinatura de classe ou removendo classes ou campos de classe.
• Os implementadores de dispositivos PODEM modificar a implementação subjacente das APIs, mas tais modificações NÃO DEVEM afetar o comportamento declarado e a assinatura da linguagem Java de quaisquer APIs expostas publicamente.
• Os implementadores de dispositivos NÃO DEVEM adicionar quaisquer elementos expostos publicamente (como classes ou interfaces, ou campos ou métodos para classes ou interfaces existentes) às APIs acima.

Um “elemento exposto publicamente” é qualquer construção que não seja decorada com o marcador “@hide” conforme usado no código-fonte do Android upstream. Em outras palavras, os implementadores de dispositivos NÃO DEVEM expor novas APIs ou alterar as APIs existentes nos namespaces mencionados acima. Os implementadores de dispositivos PODEM fazer modificações apenas internas, mas essas modificações NÃO DEVEM ser anunciadas ou expostas aos desenvolvedores.

Os implementadores de dispositivos PODEM adicionar APIs personalizadas, mas essas APIs NÃO DEVEM estar em um namespace pertencente ou referente a outra organização. Por exemplo, os implementadores de dispositivos NÃO DEVEM adicionar APIs ao com.google.* ou namespace semelhante: somente o Google pode fazer isso. Da mesma forma, o Google NÃO DEVE adicionar APIs a namespaces de outras empresas. Além disso, se uma implementação de dispositivo incluir APIs personalizadas fora do namespace padrão do Android, essas APIs DEVEM ser empacotadas em uma biblioteca compartilhada do Android para que apenas os aplicativos que as usem explicitamente (por meio do mecanismo <uses-library>) sejam afetados pelo aumento do uso de memória de tais APIs.

Se um implementador de dispositivo propõe melhorar um dos namespaces de pacotes acima (como adicionar uma nova funcionalidade útil a uma API existente ou adicionar uma nova API), o implementador DEVE visitar source.android.com e iniciar o processo de contribuição de alterações e código, de acordo com as informações desse site.

Observe que as restrições acima correspondem às convenções padrão para nomear APIs na linguagem de programação Java; esta seção visa simplesmente reforçar essas convenções e torná-las vinculativas através da inclusão nesta Definição de Compatibilidade.

3.7. Compatibilidade do tempo de execução

As implementações de dispositivos DEVEM suportar o formato Dalvik Executable (DEX) completo e a especificação e semântica de bytecode Dalvik [ Recursos, 20 ]. Os implementadores de dispositivos DEVEM usar o ART, a implementação upstream de referência do Dalvik Executable Format e o sistema de gerenciamento de pacotes da implementação de referência.

As implementações de dispositivos DEVEM configurar os tempos de execução da Dalvik para alocar memória de acordo com a plataforma Android upstream e conforme especificado pela tabela a seguir. (Consulte a seção 7.1.1 para definições de tamanho de tela e densidade de tela.)

Observe que os valores de memória especificados abaixo são considerados valores mínimos e as implementações de dispositivos PODEM alocar mais memória por aplicativo.

3.8. Compatibilidade da interface do usuário

3.8.1. Iniciador (tela inicial)

O Android inclui um aplicativo inicializador (tela inicial) e suporte para aplicativos de terceiros para substituir o inicializador do dispositivo (tela inicial). As implementações de dispositivos que permitem que aplicativos de terceiros substituam a tela inicial do dispositivo DEVEM declarar o recurso de plataforma android.software.home_screen.

3.8.2. Widgets

O Android define um tipo de componente e API correspondente e ciclo de vida que permite que os aplicativos exponham um “AppWidget” ao usuário final [ Recursos, 21 ] um recurso que é altamente RECOMENDADO para ser suportado em implementações de dispositivos portáteis. As implementações de dispositivos que suportam a incorporação de widgets na tela inicial DEVEM atender aos seguintes requisitos e declarar suporte para o recurso de plataforma android.software.app_widgets.

• Os lançadores de dispositivos DEVEM incluir suporte integrado para AppWidgets e expor recursos da interface do usuário para adicionar, configurar, visualizar e remover AppWidgets diretamente no Launcher.
• As implementações de dispositivos DEVEM ser capazes de renderizar widgets que são 4 x 4 no tamanho padrão da grade. Consulte as Diretrizes de design do widget de aplicativo na documentação do Android SDK [ Recursos, 21 ] para obter detalhes.
• As implementações de dispositivos que incluem suporte para tela de bloqueio PODEM oferecer suporte a widgets de aplicativos na tela de bloqueio.

3.8.3. Notificações

O Android inclui APIs que permitem que os desenvolvedores notifiquem os usuários sobre eventos notáveis ​​[ Recursos, 22 ], usando recursos de hardware e software do dispositivo.

Algumas APIs permitem que os aplicativos executem notificações ou chamem a atenção usando hardware, especificamente som, vibração e luz. As implementações de dispositivos DEVEM oferecer suporte a notificações que usam recursos de hardware, conforme descrito na documentação do SDK e, na medida do possível, com o hardware de implementação do dispositivo. Por exemplo, se uma implementação de dispositivo inclui um vibrador, DEVE implementar corretamente as APIs de vibração. Se a implementação de um dispositivo não tiver hardware, as APIs correspondentes DEVEM ser implementadas como no-ops. Esse comportamento é detalhado na seção 7 .

Além disso, a implementação DEVE renderizar corretamente todos os recursos (ícones , arquivos de animação etc.) O dispositivo Android Television inclui a possibilidade de não exibir as notificações. Os implementadores de dispositivos PODEM fornecer uma experiência de usuário alternativa para notificações do que a fornecida pela implementação de referência do Android Open Source; no entanto, esses sistemas alternativos de notificação DEVEM suportar recursos de notificação existentes, como acima.

O Android inclui suporte para várias notificações, como:

• Notificações ricas . Visualizações interativas para notificações em andamento.
• Notificações de alerta . Os usuários do Interactive Views podem agir ou dispensar sem sair do aplicativo atual.
• Notificações da tela de bloqueio. Notificações exibidas em uma tela de bloqueio com controle granular da visibilidade.

As implementações de dispositivos Android, quando tais notificações se tornam visíveis, DEVEM executar corretamente as notificações Rich e Heads-up e incluir o título/nome, ícone, texto conforme documentado nas APIs do Android [Recursos, 25] .

O Android inclui APIs do Notification Listener Service que permitem que os aplicativos (uma vez habilitados explicitamente pelo usuário) recebam uma cópia de todas as notificações à medida que são postadas ou atualizadas. As implementações de dispositivos DEVEM enviar notificações completas de forma correta e imediata para todos os serviços de escuta instalados e habilitados pelo usuário, incluindo todos e quaisquer metadados anexados ao objeto Notificação.

3.8.4. Procurar

O Android inclui APIs [ Recursos, 26 ] que permitem que os desenvolvedores incorporem a pesquisa em seus aplicativos e exponham os dados de seus aplicativos na pesquisa global do sistema. De um modo geral, essa funcionalidade consiste em uma única interface de usuário em todo o sistema que permite aos usuários inserir consultas, exibir sugestões à medida que os usuários digitam e exibe resultados. As APIs do Android permitem que os desenvolvedores reutilizem essa interface para fornecer pesquisa em seus próprios aplicativos e permitem que os desenvolvedores forneçam resultados à interface de usuário de pesquisa global comum.

As implementações de dispositivos Android DEVEM incluir pesquisa global, uma interface de usuário de pesquisa única, compartilhada e em todo o sistema capaz de sugestões em tempo real em resposta à entrada do usuário. As implementações de dispositivos DEVEM implementar as APIs que permitem que os desenvolvedores reutilizem essa interface do usuário para fornecer pesquisa em seus próprios aplicativos. As implementações de dispositivos que implementam a interface de pesquisa global DEVEM implementar as APIs que permitem que aplicativos de terceiros adicionem sugestões à caixa de pesquisa quando ela é executada no modo de pesquisa global. Se nenhum aplicativo de terceiros estiver instalado que faça uso dessa funcionalidade, o comportamento padrão DEVE ser exibir resultados e sugestões do mecanismo de pesquisa na web.

3.8.5. Torradas

Os aplicativos podem usar a API “Toast” para exibir strings não modais curtas para o usuário final, que desaparecem após um breve período de tempo [ Recursos, 27 ]. As implementações de dispositivos DEVEM exibir brindes de aplicativos para usuários finais de alguma maneira de alta visibilidade.

3.8.6. Temas

O Android fornece “temas” como um mecanismo para aplicativos aplicarem estilos em uma atividade ou aplicativo inteiro.

O Android inclui uma família de temas “Holo” como um conjunto de estilos definidos para os desenvolvedores de aplicativos usarem se quiserem combinar a aparência do tema Holo conforme definido pelo Android SDK [ Recursos, 28 ]. As implementações de dispositivos NÃO DEVEM alterar nenhum dos atributos do tema Holo expostos aos aplicativos [ Recursos, 29 ].

O Android inclui uma família de temas “Material” como um conjunto de estilos definidos para os desenvolvedores de aplicativos usarem se quiserem combinar a aparência do tema de design em uma ampla variedade de diferentes tipos de dispositivos Android. As implementações de dispositivos DEVEM suportar a família de temas “Material” e NÃO DEVEM alterar nenhum dos atributos do tema Material ou seus ativos expostos aos aplicativos [ Recursos, 30 ].

O Android também inclui uma família de temas “Device Default” como um conjunto de estilos definidos para os desenvolvedores de aplicativos usarem se quiserem combinar a aparência do tema do dispositivo conforme definido pelo implementador do dispositivo. Implementações de dispositivos podem modificar os atributos do tema Device Default expostos a aplicativos [ Recursos, 29 ].

O Android oferece suporte a um novo tema variante com barras de sistema translúcidas, que permitem que os desenvolvedores de aplicativos preencham a área atrás da barra de status e navegação com o conteúdo do aplicativo. Para permitir uma experiência de desenvolvedor consistente nesta configuração, é importante que o estilo do ícone da barra de status seja mantido em diferentes implementações de dispositivos. Portanto, as implementações de dispositivos Android DEVEM usar branco para ícones de status do sistema (como intensidade do sinal e nível da bateria) e notificações emitidas pelo sistema, a menos que o ícone indique um status problemático [ Recursos, 29 ].

3.8.7. Papel de parede animados

O Android define um tipo de componente e API e ciclo de vida correspondentes que permitem que os aplicativos exponham um ou mais “Live Wallpapers” ao usuário final [ Resources, 31 ]. Papéis de parede animados são animações, padrões ou imagens semelhantes com recursos de entrada limitados que são exibidos como papel de parede, atrás de outros aplicativos.

O hardware é considerado capaz de executar papéis de parede ao vivo de forma confiável se puder executar todos os papéis de parede ao vivo, sem limitações de funcionalidade, a uma taxa de quadros razoável sem efeitos adversos em outros aplicativos. Se as limitações do hardware causarem falhas nos papéis de parede e/ou aplicativos, mau funcionamento, consumo excessivo de CPU ou energia da bateria ou execução em taxas de quadros inaceitavelmente baixas, o hardware será considerado incapaz de executar o papel de parede ao vivo. Como exemplo, alguns papéis de parede ao vivo podem usar um contexto OpenGL 2.0 ou 3.x para renderizar seu conteúdo. O papel de parede ao vivo não será executado de forma confiável em hardware que não oferece suporte a vários contextos OpenGL porque o uso do papel de parede ao vivo de um contexto OpenGL pode entrar em conflito com outros aplicativos que também usam um contexto OpenGL.

As implementações de dispositivos capazes de executar papéis de parede ao vivo de forma confiável, conforme descrito acima, DEVEM implementar papéis de parede ao vivo e, quando implementados, DEVEM relatar o sinalizador de recurso da plataforma android.software.live_wallpaper.

3.8.8. Troca de atividade

O código-fonte do Android upstream inclui a tela de visão geral [ Resources, 32 ], uma interface de usuário em nível de sistema para alternar tarefas e exibir atividades e tarefas acessadas recentemente usando uma imagem em miniatura do estado gráfico do aplicativo no momento em que o usuário deixou o aplicativo pela última vez. As implementações de dispositivos, incluindo a tecla de navegação da função recente, conforme detalhado na seção 7.2.3 , PODEM alterar a interface, mas DEVEM atender aos seguintes requisitos:

• DEVE exibir recentes afiliados como um grupo que se move em conjunto.
• DEVE suportar pelo menos até 20 atividades exibidas.
• DEVE exibir pelo menos o título de 4 atividades por vez.
• DEVE exibir cor de destaque, ícone, título da tela em recentes.
• DEVE implementar o comportamento de fixação de tela [ Recursos, 33 ] e fornecer ao usuário um menu de configurações para alternar o recurso.
• DEVE exibir um affordance de fechamento ("x"), mas PODE atrasá-lo até que o usuário interaja com as telas.

As implementações de dispositivos são FORTEMENTE INCENTIVADAS a usar a interface de usuário do Android upstream (ou uma interface semelhante baseada em miniaturas) para a tela de visão geral.

3.8.9. Gerenciamento de entrada

O Android inclui suporte para gerenciamento de entrada e suporte para editores de métodos de entrada de terceiros [ Recursos, 34 ]. As implementações de dispositivos que permitem que os usuários usem métodos de entrada de terceiros no dispositivo DEVEM declarar o recurso de plataforma android.software.input_methods e oferecer suporte a APIs IME, conforme definido na documentação do Android SDK.

As implementações de dispositivos que declaram o recurso android.software.input_methods DEVEM fornecer um mecanismo acessível ao usuário para adicionar e configurar métodos de entrada de terceiros. As implementações de dispositivos DEVEM exibir a interface de configurações em resposta à intenção android.settings.INPUT_METHOD_SETTINGS.

3.8.10. Controle de mídia da tela de bloqueio

A API do cliente de controle remoto está obsoleta do Android 5.0 em favor do modelo de notificação de mídia que permite que aplicativos de mídia se integrem aos controles de reprodução exibidos na tela de bloqueio [ Recursos, 35 ]. As implementações de dispositivos que suportam uma tela de bloqueio, a menos que uma implementação do Android Automotive ou Watch, DEVEM exibir as notificações da tela de bloqueio, incluindo o modelo de notificação de mídia.

3.8.11. Sonhos

O Android inclui suporte para protetores de tela interativos chamados Dreams [ Recursos, 36 ]. O Dreams permite que os usuários interajam com aplicativos quando um dispositivo conectado a uma fonte de energia está ocioso ou encaixado em uma estação de trabalho. Dispositivos Android Watch PODEM implementar Dreams, mas outros tipos de implementações de dispositivos DEVEM incluir suporte para Dreams e fornecer uma opção de configurações para os usuários configurarem Dreams em resposta à intenção android.settings.DREAM_SETTINGS.

3.8.12. Localização

Quando um dispositivo possui um sensor de hardware (por exemplo, GPS) capaz de fornecer as coordenadas de localização, os modos de localização DEVEM ser exibidos no menu Localização em Configurações [ Recursos, 37 ].

3.8.13. Unicode e fonte

O Android inclui suporte para caracteres emoji coloridos. Quando implementações de dispositivos Android incluem um IME, os dispositivos DEVEM fornecer um método de entrada para o usuário para os caracteres Emoji definidos no Unicode 6.1 [ Recursos, 38 ]. Todos os dispositivos DEVEM ser capazes de renderizar esses caracteres emoji em glifo de cores.

O Android inclui suporte para a fonte Roboto 2 com pesos diferentes - sans-serif-thin, sans-serif-light, sans-serif-medium, sans-serif-black, sans-serif-condensed, sans-serif-condensed-light - que DEVEM estar todos incluídos para os idiomas disponíveis no dispositivo e cobertura completa do Unicode 7.0 para latim, grego e cirílico, incluindo os intervalos Latin Extended A, B, C e D, e todos os glifos no bloco de símbolos de moeda do Unicode 7.0.

3.9. Administração do dispositivo

O Android inclui recursos que permitem que aplicativos com reconhecimento de segurança executem funções de administração de dispositivos no nível do sistema, como aplicar políticas de senha ou realizar limpeza remota, por meio da API de administração de dispositivos Android [ Recursos, 39 ]. Implementações de dispositivos devem fornecer uma implementação da classe DevicePolicyManager [ Recursos, 40 ]. As implementações de dispositivos que incluem suporte para telas de bloqueio baseadas em PIN (numérico) ou SENHA (alfanumérico) DEVEM oferecer suporte a toda a gama de políticas de administração de dispositivos definidas na documentação do Android SDK [ Recursos, 39 ] e relatar o recurso de plataforma android.software.device_admin.

As implementações de dispositivos PODEM ter um aplicativo pré-instalado executando funções de administração do dispositivo, mas esse aplicativo NÃO DEVE ser definido como o aplicativo padrão do Proprietário do Dispositivo [ Recursos, 41 ].

3.10. Acessibilidade

O Android fornece uma camada de acessibilidade que ajuda os usuários com deficiência a navegar em seus dispositivos com mais facilidade. Além disso, o Android fornece APIs de plataforma que permitem que implementações de serviços de acessibilidade recebam retornos de chamada para eventos do usuário e do sistema e gerem mecanismos alternativos de feedback, como conversão de texto em fala, feedback tátil e navegação trackball/d-pad [ Resources, 42 ].

As implementações de dispositivos incluem os seguintes requisitos:

• As implementações do Android Automotive DEVEM fornecer uma implementação da estrutura de acessibilidade do Android consistente com a implementação padrão do Android.
• As implementações de dispositivos (excluindo o Android Automotive) DEVEM fornecer uma implementação da estrutura de acessibilidade do Android consistente com a implementação padrão do Android.
• As implementações de dispositivos (excluindo o Android Automotive) DEVEM oferecer suporte a implementações de serviços de acessibilidade de terceiros por meio das APIs android.accessibilityservice [ Recursos, 43 ]
• As implementações de dispositivos (excluindo o Android Automotive) DEVEM gerar AccessibilityEvents e entregar esses eventos a todas as implementações de AccessibilityService registradas de maneira consistente com a implementação padrão do Android
• As implementações de dispositivos (dispositivos Android Automotive e Android Watch sem saída de áudio excluídas) DEVEM fornecer um mecanismo acessível ao usuário para ativar e desativar serviços de acessibilidade e DEVEM exibir essa interface em resposta à intenção android.provider.Settings.ACTION_ACCESSIBILITY_SETTINGS.

Além disso, as implementações do dispositivo DEVEM fornecer uma implementação de um serviço de acessibilidade no dispositivo e DEVEM fornecer um mecanismo para os usuários habilitarem o serviço de acessibilidade durante a configuração do dispositivo. Uma implementação de código aberto de um serviço de acessibilidade está disponível no projeto Eyes Free [ Recursos, 44 ].

3.11. Text-to-Speech

O Android inclui APIs que permitem que aplicativos usem serviços de conversão de texto em fala (TTS) e permite que provedores de serviços forneçam implementações de serviços TTS [ Recursos, 45 ]. As implementações de dispositivos que relatam o recurso android.hardware.audio.output DEVEM atender a esses requisitos relacionados à estrutura do Android TTS.

Implementações do Android Automotive:

• DEVE ser compatível com as APIs da estrutura Android TTS.
• PODE apoiar a instalação de mecanismos TTS de terceiros. Se houver suporte, os parceiros DEVEM fornecer uma interface acessível ao usuário que permita ao usuário selecionar um mecanismo TTS para uso no nível do sistema.

Todas as outras implementações de dispositivos:

• DEVE ser compatível com as APIs da estrutura Android TTS e DEVE incluir um mecanismo TTS compatível com os idiomas disponíveis no dispositivo. Observe que o software de código aberto do Android upstream inclui uma implementação de mecanismo TTS com todos os recursos.
• DEVE suportar a instalação de mecanismos TTS de terceiros
• DEVE fornecer uma interface acessível ao usuário que permita aos usuários selecionar um mecanismo TTS para uso no nível do sistema

3.12. Estrutura de entrada de TV

O Android Television Input Framework (TIF) simplifica a entrega de conteúdo ao vivo para dispositivos Android Television. TIF fornece uma API padrão para criar módulos de entrada que controlam dispositivos Android Television. As implementações de dispositivos Android Television DEVEM oferecer suporte ao Television Input Framework [ Recursos, 46 ].

As implementações de dispositivos que suportam TIF DEVEM declarar o recurso de plataforma android.software.live_tv.

4. Compatibilidade de Embalagem de Aplicativo

As implementações de dispositivos DEVEM instalar e executar arquivos “.apk” do Android conforme gerados pela ferramenta “aapt” incluída no SDK oficial do Android [ Recursos, 47 ].

As implementações de dispositivos NÃO DEVEM estender os formatos de bytecode .apk [ Resources, 48 ​​], Android Manifest [ Resources, 49 ], Dalvik bytecode [ Resources, 20 ] ou RenderScript de forma a impedir que esses arquivos sejam instalados e executados corretamente em outros dispositivos compatíveis.

5. Compatibilidade Multimídia

5.1. Codecs de mídia

As implementações de dispositivos DEVEM oferecer suporte aos principais formatos de mídia especificados na documentação do Android SDK [ Recursos, 50 ], exceto onde explicitamente permitido neste documento. Especificamente, as implementações de dispositivos DEVEM suportar os formatos de mídia, codificadores, decodificadores, tipos de arquivo e formatos de contêiner definidos nas tabelas abaixo e relatados via MediaCodecList [ Recursos,112 ]. Implementações de dispositivos também devem ser capazes de decodificar todos os perfis relatados em seu CamcorderProfile [ Recursos, 113 ]. Todos esses codecs são fornecidos como implementações de software na implementação Android preferida do Android Open Source Project.

Observe que nem o Google nem a Open Handset Alliance declaram que esses codecs estão livres de patentes de terceiros. Aqueles que pretendem usar este código-fonte em produtos de hardware ou software são informados de que as implementações deste código, inclusive em software de código aberto ou shareware, podem exigir licenças de patentes dos detentores de patente relevantes.

5.1.1. Codecs de áudio

1 Obrigatório para implementações de dispositivos que definem android.hardware.microphone, mas opcional para implementações de dispositivos Android Watch.

2 É necessário apenas downmix de conteúdo 5.0/5.1; gravar ou renderizar mais de 2 canais é opcional.

3 Necessário para implementações de dispositivos portáteis Android.

4 Necessário para implementações de dispositivos que definem android.hardware.microphone, incluindo implementações de dispositivos Android Watch.

5.1.2. Codecs de imagem

5.1.3. Codecs de vídeo

Codecs de vídeo são opcionais para implementações de dispositivos Android Watch.

1 Necessário para implementações de dispositivos que incluem hardware de câmera e definem android.hardware.camera ou android.hardware.camera.front.

2 Necessário para implementações de dispositivos, exceto dispositivos Android Watch.

3 Para qualidade aceitável de streaming de vídeo na web e serviços de videoconferência, implementações de dispositivos DEVEM usar um codec de hardware VP8 que atenda aos requisitos em [ Recursos, 51 ].

4 As implementações de dispositivos DEVEM suportar a gravação de arquivos Matroska WebM.

5 Fortemente recomendado para Android Automotive, opcional para Android Watch e obrigatório para todos os outros tipos de dispositivos.

5.2. Codificação de vídeo

As implementações de dispositivos Android com suporte a codec H.264, DEVEM oferecer suporte ao Perfil de Linha de Base Nível 3 e os seguintes perfis de codificação de vídeo SD (Definição Padrão) e DEVEM oferecer suporte ao Perfil Principal Nível 4 e os seguintes perfis de codificação de vídeo HD (Alta Definição). Os dispositivos Android Television são FORTEMENTE RECOMENDADOS para codificar vídeo HD 1080p a 30 fps.

1 Quando suportado por hardware, mas FORTEMENTE RECOMENDADO para dispositivos Android Television.

As implementações de dispositivos Android com suporte a codec VP8 DEVEM suportar os perfis de codificação de vídeo SD e DEVEM suportar os seguintes perfis de codificação de vídeo HD (Alta Definição).

1 Quando suportado por hardware.

5.3. Decodificação de vídeo

As implementações de dispositivos DEVEM oferecer suporte à comutação dinâmica de resolução de vídeo no mesmo fluxo para todos os codecs VP8, VP9, ​​H.264 e H.265 expostos aos desenvolvedores por meio das APIs padrão do Android.

As implementações de dispositivos Android com decodificadores H.264 DEVEM oferecer suporte ao Perfil Baseline Nível 3 e os seguintes perfis de decodificação de vídeo SD e DEVEM oferecer suporte aos perfis de decodificação HD. Os dispositivos Android Television DEVEM ser compatíveis com o High Profile Level 4.2 e o perfil de decodificação HD 1080p.

1 Required for Android Television device implementations, but for other device types only when supported by hardware.

2 Required for Android Television device implementations.

Android device implementations when supporting VP8 codec as described in section 5.1.3 , MUST support the following SD decoding profiles and SHOULD support the HD decoding profiles. Android Television devices MUST support the HD 1080p decoding profile.

1 Required for Android Television device implementations, but for other type of devices only when supported by hardware.

2 Required for Android Television device implementations.

Android device implementations, when supporting VP9 codec as described in section 5.1.3 , MUST support the following SD video decoding profiles and SHOULD support the HD decoding profiles. Android Television devices are STRONGLY RECOMMENDED to support the HD 1080p decoding profile and SHOULD support the UHD decoding profile. When the UHD video decoding profile is supported, it MUST support 8 bit color depth.

1 Required for Android Television device implementations, but for other type of devices only when supported by hardware.

2 STRONGLY RECOMMENDED for Android Television device implementations when supported by hardware.

Android device implementations, when supporting H.265 codec as described in section 5.1.3 , MUST support the Main Profile Level 3 Main tier and the following SD video decoding profiles and SHOULD support the HD decoding profiles. Android Television devices SHOULD support Main10 Level 5 Main Tier profile and the UHD decoding profile. Android Television devices are 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

1 Required for Android Television device implementation, but for other type of devices only when supported by hardware.

2 STRONGLY RECOMMENDED for Android Television device implementations when supported by hardware.

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

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

5.4.2. Capture for Voice Recognition

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 1Khz 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 [ Resources, 52 ]. 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).

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 can be heard by an external listener or observed by a transducer.
• 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 an external sound is presented to the device and when an application reads the corresponding frame of PCM-coded data.
• 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 variance among separate measurements of cold output latency values.
• cold input jitter . The variance among separate measurements of cold input latency values.
• continuous round-trip latency . The sum of continuous input latency plus continuous output latency plus 5 milliseconds.
• OpenSL ES PCM buffer queue API . The set of PCM-related OpenSL ES APIs within Android NDK; see NDK_root/docs/opensles/index.html.

Device implementations that declare android.hardware.audio.output SHOULD 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 MAY report support for low-latency audio, by reporting the feature android.hardware.audio.low_latency via the android.content.pm.PackageManager class [ Resources, 53 ]. 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 SHOULD 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 [ Resources, 50 ]. Specifically, devices MUST support the following media network protocols:

• RTSP (RTP, SDP)
• HTTP(S) progressive streaming
• HTTP(S) Live Streaming draft protocol, Version 3 [ Resources, 54 ]

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.

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) [ Resources, 55 ]

Device implementations MUST support all adb functions as documented in the Android SDK including dumpsys [ Resources, 56 ]. 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) [ Resources, 57 ]

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 [ Resources, 58 ]

Device implementations MUST include the Monkey framework, and make it available for applications to use.

• SysTrace [ Resources, 59 ]

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 9 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 [ Resources, 60 ]. 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.

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. [ Resources, 53]

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 [ Resources, 61 ]. 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

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 [ Resources, 61 ] 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.
• 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

The screen aspect ratio MUST be a value from 1.3333 (4:3) to 1.86 (roughly 16:9), but Android Watch devices MAY have an aspect ratio of 1.0 (1:1) because such a device implementation will use a UI_MODE_TYPE_WATCH as the android.content.res.Configuration.uiMode.

7.1.1.3. Screen Density

The Android UI framework defines a set of standard logical densities to help application developers target application resources. Device implementations MUST report only one of the following logical Android framework densities through the android.util.DisplayMetrics APIs, and MUST execute applications at this standard density and MUST NOT change the value at at any time for the default display.

• 120 dpi (ldpi)
• 160 dpi (mdpi)
• 213 dpi (tvdpi)
• 240 dpi (hdpi)
• 280 dpi (280dpi)
• 320 dpi (xhdpi)
• 400 dpi (400 dpi)
• 480 dpi (xxhdpi)
• 560 dpi (560dpi)
• 640 dpi (xxxhdpi)

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.

7.1.2. Display Metrics

Device implementations MUST report correct values for all display metrics defined in android.util.DisplayMetrics [ Resources, 62 ] 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 or 3.1 on devices capable of supporting it. Device implementations MUST also support Android RenderScript, as detailed in the Android SDK documentation [ Resources, 63 ].

Device implementations MUST also correctly identify themselves as supporting OpenGL ES 1.0, OpenGL ES 2.0, OpenGL ES 3.0 or OpenGL 3.1. 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 or 3.1 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 or 3.1, libGLESv2.so MUST export the corresponding function symbols in addition to the OpenGL ES 2.0 function symbols.

In addition to OpenGL ES 3.1, Android provides an extension pack with Java interfaces [ Resources, 64 ] and native support for advanced graphics functionality such as tessellation and the ASTC texture compression format. Android device implementations MAY support this extension pack, and—only if fully implemented—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 [ Resources, 65 ].

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 [ Resources, 65 ].

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 [ Resources, 66 ].

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 [ Resources, 67 ].

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

Implementações 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 [ Resources, 68 ] (QWERTY or 12-key).

7.2.2. Non-touch Navigation

Implementações 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 [ Resources, 68 ].
• 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 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 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 5.0 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 5.1, 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 supports Assist action [ Resources, 69 ]. Android device implementations except for Android Watch devices MUST make the Assist action available to the user at all times when running applications. The Assist action SHOULD be implemented as a long-press on the Home button or a swipe-up gesture on the software Home key. This function MAY be implemented via another physical button, software key, or gesture, but MUST be accessible with a single action (eg tap, double-click, or gesture) when other navigation keys are visible.

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

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 [ Resources, 68 ] 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 [ Resources, 70 ] 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 [ Resources, 71 ].
• 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 [ Resources, 71 ].
• 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 [ Resources, 71 ].
• 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:

1 [ Resources, 72 ]

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 [ Resources, 71 ]

1 [ Resources, 71 ]

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 when the user invokes voice search either on the physical or software-based remote.
• Navigation . All Android Television remotes MUST include Back, Home, and Select buttons and support for D-pad events [ Resources, 72 ].

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 [ Resources, 73 ]. For example, device implementations:

• MUST accurately report the presence or absence of sensors per the android.content.pm.PackageManager class [ Resources, 53] .
• 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 [ Resources, 74 ].
• 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 very strongly encouraged to meet these requirement 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 [ Resources, 75 ].

The list above is not comprehensive; the documented behavior of the Android SDK and the Android Open Source Documentations on Sensors [ Resources, 73 ] 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 [ Resources, 76 ]. If a device implementation includes a composite sensor it MUST implement the sensor as described in the Android Open Source documentation on composite sensors [ Resources, 76 ].

Some Android sensors support a “continuous” trigger mode, which returns data continuously [ Resources, 77 ]. 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. Acelerômetro

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

• MUST implement and report TYPE_ACCELEROMETER sensor [ Resources, 78 ].
• 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 [ Resources, 74 ].
• 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 8-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 very strongly encouraged 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 encouraged to implement the TYPE_GAME_ROTATION_VECTOR sensor.
• SHOULD 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 encouraged 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 [ Resources, 74 ].
• 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 µ.
• 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.
• SHOULD 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 receiver. If a device implementation does include a GPS receiver, it SHOULD include some form of“assisted GPS” technique to minimize GPS lock-on time.

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 encouraged 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.
• SHOULD 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 encouraged 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.

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.

7.4. 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.

7.4.2. IEEE 802.11 (Wi-Fi)

Android Television device implementations MUST include support for one or more forms of 802.11 (b/g/a/n, etc.) and other types of Android device implementation 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 [ Resources, 79 ].
• MUST support multicast DNS (mDNS) and MUST NOT filter mDNS packets (224.0.0.251) at any time of operation including when the screen is not in an active state.

7.4.2.1. Wi-Fi Direto

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 [ Resources, 80 ]. 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.

7.4.2.2. Wi-Fi Tunneled Direct Link Setup

Android Television device implementations MUST include support for Wi-Fi Tunneled Direct Link Setup (TDLS) and other types of Android device implementations SHOULD include support for Wi-Fi TDLS as described in the Android SDK Documentation [ Resources, 81 ]. 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 includes support for Bluetooth and Bluetooth Low Energy [ Resources, 82 ]. 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 Television device implementations MUST support Bluetooth and Bluetooth LE.

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 [ Resources, 82 ].
• SHOULD support offloading of the filtering logic to the bluetooth chipset when implementing the ScanFilter API [ Resources, 83 ], 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.BluetoothAdapater.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 [ Resources, 53 ].
• 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 6319-4)
    • IsoDep (ISO 14443-4)
    • NFC Forum Tag Types 1, 2, 3, 4 (defined by the NFC Forum)
  • SHOULD be capable of reading and writing NDEF messages via the following NFC standards. Note that while the NFC standards below are stated as SHOULD, 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)
  • MUST be capable of transmitting and receiving data via the following peer-to-peer standards and protocols:
    • ISO 18092
    • LLCP 1.0 (defined by the NFC Forum)
    • SDP 1.0 (defined by the NFC Forum)
    • NDEF Push Protocol [ Resources, 84 ]
    • SNEP 1.0 (defined by the NFC Forum)
  • MUST include support for Android Beam [ Resources, 85 ]:
    • 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 [ Resources, 86 ].
    • 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” [ Resources, 87 ] and “Bluetooth Secure Simple Pairing Using NFC version 1.0” [ Resources, 88 ] 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 and 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 [ Resources, 10 ].

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() meth od [Resources, 53] . Note that this is not a standard Android feature and as such does not appear as a constant on the 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 [ Resources, 53] , 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.

7.4.6. Sync Settings

Device implementations MUST have the master auto-sync setting on by default so that the method getMasterSyncAutomatically() returns “true” [ Resources, 89 ].

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 SHOULD be possible for an application to simultaneously allocate 3 bitmaps equal to the size of the images produced by the largest-resolution camera sensor on the device.

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()[ Resources, 90 ] 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 with USB host mode MAY include support for an external camera that connects to the USB port. If a device includes support for an external camera, it:

• MUST declare the platform feature android.hardware.camera.external and android.hardware camera.any.
• MUST support USB Video Class (UVC 1.0 or higher).
• MAY support multiple cameras.

Video compression (such as MJPEG) support is RECOMMENDED to enable transfer of high-quality unencoded streams (ie raw or independently compressed picture streams). Camera-based video encoding MAY be supported. If so, 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 [ Resources, 91 ], 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 [ Resources, 92 ].

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 [ Resources, 93] and report the appropriate framework feature flags [ Resources, 94] .

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 [ Resources, 94] ; 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

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.)

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 5GB and other device implementations MUST have at least 1.5GB of non-volatile storage available for application private data. That is, the /data partition MUST be at least 5GB for Android Television devices and at least 1.5GB for other device implementations. Device implementations that run Android are very strongly encouraged to have at least 3GB 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 [ Resources, 95 ]. 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 Linux path /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 and 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 [ Resources, 96 ].
• SHOULD report a USB device class of 0x00.
• SHOULD report a USB interface name of 'MTP'.

7.7. USB

Device implementations SHOULD support USB peripheral mode and SHOULD support USB host 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 future platform releases.
• The port SHOULD either 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 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 [ Resources, 97 ].
  • MUST implement the USB audio class as documented in the Android SDK documentation [ Resources, 98 ].
• 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 [ Resources, 99 ]. 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 value of iSerialNumber in USB standard device descriptor MUST be equal to the value of android.os.Build.SERIAL.

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 very strongly RECOMMENDED to implement the USB audio class as documented in the Android SDK documentation [ Resources, 98 ].
• 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 [ Resources, 100 ].
• SHOULD support the Charging Downstream Port output current range of 1.5 A ~ 5 A as specified in the USB Battery Charging Specification, Revision 1.2 [ Resources, 99 ].

7.8. Audio

7.8.1. Microfone

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

7.8.2. 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 .

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 [ Resources, 101 ], 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.
• SHOULD 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
• SHOULD support the detection and mapping 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.

8. Performance Compatibility

Some minimum performance criterias are critical to the user experience and impacts 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.

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 [ Resources, 102 ] 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. Permissões

Device implementations MUST support the Android permissions model as defined in the Android developer documentation [ Resources, 102 ]. 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.

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 [ Resources, 102 ].

9.3. Filesystem Permissions

Device implementations MUST support the Android file access permissions model as defined in the Security and Permissions reference [ Resources, 102 ].

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.
• and 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

Android includes support for multiple users and provides support for full user isolation [ Resources, 103] . Device implementations MAY enable multiple users, but when enabled MUST meet the following requirements related to multi-user support [ Resources, 104 ]:

• 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 [ Resources, 102 ].
• Device implementations MAY support creating users and managed profiles via the android.app.admin.DevicePolicyManager APIs, and if supported, MUST declare the platform feature flag android.software.managed_users.
• Device implementations that declare the feature flag android.software.managed_users MUST use the upstream AOSP icon badge to represent the managed applications and other badge UI elements like Recents & Notifications.
• 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 primary 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 [ Resources, 105 ] for primary external storage.

9.6. Premium SMS Warning

Android includes support for warning users of any outgoing premium SMS message [ Resources, 106 ] . 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 can use the Security-Enhanced Linux (SELinux) mandatory access control (MAC) system and other security features in the Linux kernel. SELinux or any other security features, if 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 an equivalent mandatory access control system if using a kernel other than Linux and meet the following requirements, which are satisfied by the reference implementation in the upstream Android Open Source Project.

Implementações de dispositivos:

• MUST support a SELinux policy that allows the SELinux mode to be set on a per-domain basis, and MUST configure all domains in enforcing mode. No permissive mode domains are allowed, including domains specific to a device/vendor.
• SHOULD load policy from /sepolicy file on the device.
• MUST NOT modify, omit, or replace the neverallow rules present within the sepolicy file provided in the upstream Android Open Source Project (AOSP) and the policy MUST compile with all neverallow present, for both AOSP SELinux domains as well as device/vendor specific domains.
• MUST support dynamic updates of the SELinux policy file without requiring a system image update.

Device implementations SHOULD retain the default SELinux policy provided in the upstream Android Open Source Project, until they have first audited their additions to the SELinux policy. Device implementations MUST be compatible with the upstream Android Open Source Project.

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.

9.9. Full-Disk Encryption

If the device implementation supports a lock screen with PIN (numeric) or PASSWORD (alphanumeric), the device MUST support full-disk encryption of the application private data (/data partition), as well as the SD card partition if it is a permanent, non-removable part of the device [ Resources, 107 ]. For devices supporting full-disk encryption, the full-disk encryption SHOULD be enabled all the time after the user has completed the out-of-box experience. While this requirement is stated as SHOULD for this version of the Android platform, it is very strongly RECOMMENDED as we expect this to change to MUST in the future versions of Android. Encryption 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. Other than when in active use, the encryption key SHOULD be AES encrypted with the lockscreen passcode stretched using a slow stretching algorithm (eg PBKDF2 or scrypt). If the user has not specified a lockscreen passcode 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. Verified Boot

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 a 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)

Device implementations SHOULD support verified boot for device integrity. While this requirement is SHOULD for this version of the Android platform, it is strongly RECOMMENDED as we expect this to change to MUST in future versions of Android. The upstream Android Open Source Project provides a preferred implementation of this feature based on the linux kernel feature dm-verity.

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 very strongly encouraged 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) [ Resources, 108 ] 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 5.1. 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:

• Android Automotive implementations SHOULD support OTA downloads with offline update via reboot.
• All other device implementations 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 5.1 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.

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.

12. Document Changelog

The following table contains a summary of the changes to the Compatibility Definition in this release.

13. Contact Us

You can join the android-compatibility forum [Resources, 109 ] and ask for clarifications or bring up any issues that you think the document does not cover.

14. Resources

1. IETF RFC2119 Requirement Levels: http://www.ietf.org/rfc/rfc2119.txt

2. Android Open Source Project: http://source.android.com/

3. Android Television features: http://developer.android.com/reference/android/content/pm/PackageManager.html#FEATURE_LEANBACK

4. Android Watch feature: http://developer.android.com/reference/android/content/res/Configuration.html#UI_MODE_TYPE_WATCH

5. API definitions and documentation: http://developer.android.com/reference/packages.html

6. Android Permissions reference: http://developer.android.com/reference/android/Manifest.permission.html

7. android.os.Build reference: http://developer.android.com/reference/android/os/Build.html

8. Android 5.1 allowed version strings: http://source.android.com/compatibility/5.1/versions.html

9. Telephony Provider: http://developer.android.com/reference/android/provider/Telephony.html

10. Host-based Card Emulation: http://developer.android.com/guide/topics/connectivity/nfc/hce.html

11. Android Extension Pack: http://developer.android.com/guide/topics/graphics/opengl.html#aep

12. android.webkit.WebView class: http://developer.android.com/reference/android/webkit/WebView.html

13. WebView compatibility: http://www.chromium.org/

14. HTML5: http://html.spec.whatwg.org/multipage/

15. HTML5 offline capabilities: http://dev.w3.org/html5/spec/Overview.html#offline

16. HTML5 video tag: http://dev.w3.org/html5/spec/Overview.html#video

17. HTML5/W3C geolocation API: http://www.w3.org/TR/geolocation-API/

18. HTML5/W3C webstorage API: http://www.w3.org/TR/webstorage/

19. HTML5/W3C IndexedDB API: http://www.w3.org/TR/IndexedDB/

20. Dalvik Executable Format and bytecode specification: available in the Android source code, at dalvik/docs

21. AppWidgets: http://developer.android.com/guide/practices/ui_guidelines/widget_design.html

22. Notifications: http://developer.android.com/guide/topics/ui/notifiers/notifications.html

23. Application Resources: https://developer.android.com/guide/topics/resources/available-resources.html

24. Status Bar icon style guide: http://developer.android.com/design/style/iconography.html

25. Notifications Resources: https://developer.android.com/design/patterns/notifications.html

26. Search Manager: http://developer.android.com/reference/android/app/SearchManager.html

27. Toasts: http://developer.android.com/reference/android/widget/Toast.html

28. Themes: http://developer.android.com/guide/topics/ui/themes.html

29. R.style class: http://developer.android.com/reference/android/R.style.html

30. Material design: http://developer.android.com/reference/android/R.style.html#Theme_Material

31. Live Wallpapers: http://developer.android.com/reference/android/service/wallpaper/WallpaperService.html

32. Overview screen resources: http://developer.android.com/guide/components/recents.html

33. Screen pinning: https://developer.android.com/about/versions/android-5.0.html#ScreenPinning

34. Input methods: http://developer.android.com/guide/topics/text/creating-input-method.html

35. Media Notification: https://developer.android.com/reference/android/app/Notification.MediaStyle.html

36. Dreams: http://developer.android.com/reference/android/service/dreams/DreamService.html

37. Settings.Secure LOCATION_MODE:

http://developer.android.com/reference/android/provider/Settings.Secure.html#LOCATION_MODE

38. Unicode 6.1.0: http://www.unicode.org/versions/Unicode6.1.0/

39. Android Device Administration: http://developer.android.com/guide/topics/admin/device-admin.html

40. DevicePolicyManager reference: http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html

41. Android Device Owner App:

http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#isDeviceOwnerApp(java.lang.String)

42. Android Accessibility Service APIs: http://developer.android.com/reference/android/accessibilityservice/AccessibilityService.html

43. Android Accessibility APIs: http://developer.android.com/reference/android/view/accessibility/package-summary.html

44. Eyes Free project: http://code.google.com/p/eyes-free

45. Text-To-Speech APIs: http://developer.android.com/reference/android/speech/tts/package-summary.html

46. Television Input Framework: /devices/tv/index.html

47. Reference tool documentation (for adb, aapt, ddms, systrace): http://developer.android.com/tools/help/index.html

48. Android apk file description: http://developer.android.com/guide/components/fundamentals.html

49. Manifest files: http://developer.android.com/guide/topics/manifest/manifest-intro.html

50. Android Media Formats: http://developer.android.com/guide/appendix/media-formats.html

51. RTC Hardware Coding Requirements: http://www.webmproject.org/hardware/rtc-coding-requirements/

52. AudioEffect API: http://developer.android.com/reference/android/media/audiofx/AudioEffect.html

53. Android android.content.pm.PackageManager class and Hardware Features List:

http://developer.android.com/reference/android/content/pm/PackageManager.html

54. HTTP Live Streaming Draft Protocol: http://tools.ietf.org/html/draft-pantos-http-live-streaming-03

55. ADB: http://developer.android.com/tools/help/adb.html

56. Dumpsys: /devices/input/diagnostics.html

57. DDMS: http://developer.android.com/tools/debugging/ddms.html

58. Monkey testing tool: http://developer.android.com/tools/help/monkey.html

59. SysyTrace tool: http://developer.android.com/tools/help/systrace.html

60. Android Application Development-Related Settings:

http://developer.android.com/reference/android/provider/Settings.html#ACTION_APPLICATION_DEVELOPMENT_SETTINGS

61. Supporting Multiple Screens: http://developer.android.com/guide/practices/screens_support.html

62. android.util.DisplayMetrics: http://developer.android.com/reference/android/util/DisplayMetrics.html

63. RenderScript: http://developer.android.com/guide/topics/renderscript/

64. Android extension pack for OpenGL ES: https://developer.android.com/reference/android/opengl/GLES31Ext.html

65. Hardware Acceleration: http://developer.android.com/guide/topics/graphics/hardware-accel.html

66. EGL Extension-EGL_ANDROID_RECORDABLE:

http://www.khronos.org/registry/egl/extensions/ANDROID/EGL_ANDROID_recordable.txt

67. Display Manager: http://developer.android.com/reference/android/hardware/display/DisplayManager.html

68. android.content.res.Configuration: http://developer.android.com/reference/android/content/res/Configuration.html

69. Action Assist: http://developer.android.com/reference/android/content/Intent.html#ACTION_ASSIST

70. Touch Input Configuration: http://source.android.com/devices/tech/input/touch-devices.html

71. Motion Event API: http://developer.android.com/reference/android/view/MotionEvent.html

72. Key Event API: http://developer.android.com/reference/android/view/KeyEvent.html

73. Android Open Source sensors: http://source.android.com/devices/sensors

74. android.hardware.SensorEvent: http://developer.android.com/reference/android/hardware/SensorEvent.html

75. Timestamp sensor event: http://developer.android.com/reference/android/hardware/SensorEvent.html#timestamp

76. Android Open Source composite sensors: /devices/sensors/sensor-types.html#composite_sensor_type_summary

77. Continuous trigger mode: /devices/sensors/report-modes.html#continuous

78. Accelerometer sensor: http://developer.android.com/reference/android/hardware/Sensor.html#TYPE_ACCELEROMETER

79. Wi-Fi Multicast API: http://developer.android.com/reference/android/net/wifi/WifiManager.MulticastLock.html

80. Wi-Fi Direct (Wi-Fi P2P): http://developer.android.com/reference/android/net/wifi/p2p/WifiP2pManager.html

81. WifiManager API: http://developer.android.com/reference/android/net/wifi/WifiManager.html

82. Bluetooth API: http://developer.android.com/reference/android/bluetooth/package-summary.html

83. Bluetooth ScanFilter API: https://developer.android.com/reference/android/bluetooth/le/ScanFilter.html

84. NDEF Push Protocol: http://source.android.com/compatibility/ndef-push-protocol.pdf

85. Android Beam: http://developer.android.com/guide/topics/connectivity/nfc/nfc.html

86. Android NFC Sharing Settings:

http://developer.android.com/reference/android/provider/Settings.html#ACTION_NFCSHARING_SETTINGS

87. NFC Connection Handover: http://members.nfc-forum.org/specs/spec_list/#conn_handover

88. Bluetooth Secure Simple Pairing Using NFC: http://members.nfc-forum.org/apps/group_public/download.php/18688/NFCForum-AD-BTSSP_1_1.pdf

89. Content Resolver: http://developer.android.com/reference/android/content/ContentResolver.html

90. Camera orientation API: http://developer.android.com/reference/android/hardware/Camera.html#setDisplayOrientation(int)

91. Camera: http://developer.android.com/reference/android/hardware/Camera.html

92. Camera: http://developer.android.com/reference/android/hardware/Camera.Parameters.html

93. Camera hardware level: https://developer.android.com/reference/android/hardware/camera2/CameraCharacteristics.html#INFO_SUPPORTED_HARDWARE_LEVEL

94. Camera version support: http://source.android.com/devices/camera/versioning.html

95. Android DownloadManager: http://developer.android.com/reference/android/app/DownloadManager.html

96. Android File Transfer: http://www.android.com/filetransfer

97. Android Open Accessories: http://developer.android.com/guide/topics/connectivity/usb/accessory.html

98. Android USB Audio: http://developer.android.com/reference/android/hardware/usb/UsbConstants.html#USB_CLASS_AUDIO

99. USB Charging Specification: http://www.usb.org/developers/docs/devclass_docs/USB_Battery_Charging_1.2.pdf

100. USB Host API: http://developer.android.com/guide/topics/connectivity/usb/host.html

101. Wired audio headset: http://source.android.com/accessories/headset-spec.html

102. Android Security and Permissions reference: http://developer.android.com/guide/topics/security/permissions.html

103. UserManager reference: http://developer.android.com/reference/android/os/UserManager.html

104. External Storage reference: http://source.android.com/devices/storage

105. External Storage APIs: http://developer.android.com/reference/android/os/Environment.html

106. SMS Short Code: http://en.wikipedia.org/wiki/Short_code

107. Android Open Source Encryption: http://source.android.com/devices/tech/security/encryption/index.html

108. Android Compatibility Program Overview: http://source.android.com/compatibility/index.html

109. Android Compatibility forum: https://groups.google.com/forum/#!forum/android-compatibility

110. WebM project: http://www.webmproject.org/

111. Android UI_MODE_TYPE_CAR API: http://developer.android.com/reference/android/content/res/Configuration.html#UI_MODE_TYPE_CAR

112. Android MediaCodecList API: http://developer.android.com/reference/android/media/MediaCodecList.html

113. Android CamcorderProfile API: http://developer.android.com/reference/android/media/CamcorderProfile.html

Many of these resources are derived directly or indirectly from the Android SDK, and will be functionally identical to the information in that SDK's documentation. In any cases where this Compatibility Definition or the Compatibility Test Suite disagrees with the SDK documentation, the SDK documentation is considered authoritative. Any technical details provided in the references included above are considered by inclusion to be part of this Compatibility Definition.