1. Einleitung

In diesem Dokument werden die Anforderungen aufgeführt, die erfüllt sein müssen, damit Geräte mit Android 7.1 kompatibel sind.

Die Verwendung von „MUSS“, „DÜRFEN NICHT“, „ERFORDERLICH“, „SOLL“, „SOLL NICHT“, „SOLLTE“, „SOLLTE NICHT“, „EMPFOHLEN“, „KANN“ und „OPTIONAL“ erfolgt gemäß der IETF Standard definiert in RFC2119 .

Wie in diesem Dokument verwendet, ist ein „Geräteimplementierer“ oder „Implementierer“ eine Person oder Organisation, die eine Hardware-/Softwarelösung mit Android 7.1 entwickelt. Eine „Geräteimplementierung“ oder „Implementierung“ ist die so entwickelte Hardware-/Softwarelösung.

Um als mit Android 7.1 kompatibel zu gelten, MÜSSEN Geräteimplementierungen die in dieser Kompatibilitätsdefinition aufgeführten Anforderungen erfüllen, einschließlich aller durch Verweis einbezogenen Dokumente.

Wenn diese Definition oder die in Abschnitt 10 beschriebenen Softwaretests stillschweigend, mehrdeutig oder unvollständig sind, liegt es in der Verantwortung des Geräteimplementierers, die Kompatibilität mit vorhandenen Implementierungen sicherzustellen.

Aus diesem Grund ist das Android Open Source Project sowohl die Referenz als auch die bevorzugte Implementierung von Android. Geräteimplementierern wird DRINGEND EMPFOHLEN, ihre Implementierungen so weit wie möglich auf dem „Upstream“-Quellcode zu basieren, der vom Android Open Source Project verfügbar ist. Obwohl einige Komponenten hypothetisch durch alternative Implementierungen ersetzt werden können, wird dringend davon abgeraten, diese Praxis zu befolgen, da das Bestehen der Softwaretests wesentlich schwieriger wird. Es liegt in der Verantwortung des Implementierers, die vollständige Verhaltenskompatibilität mit der Standard-Android-Implementierung sicherzustellen, einschließlich der Compatibility Test Suite und darüber hinaus. Beachten Sie abschließend, dass bestimmte Komponentenersetzungen und -modifikationen in diesem Dokument ausdrücklich verboten sind.

Viele der in diesem Dokument verlinkten Ressourcen stammen direkt oder indirekt vom Android SDK und sind funktional identisch mit den Informationen in der Dokumentation dieses SDK. In allen Fällen, in denen diese Kompatibilitätsdefinition oder die Kompatibilitätstestsuite nicht mit der SDK-Dokumentation übereinstimmen, gilt die SDK-Dokumentation als maßgeblich. Alle technischen Details, die in den verlinkten Ressourcen in diesem Dokument bereitgestellt werden, gelten durch die Aufnahme als Teil dieser Kompatibilitätsdefinition.

2. Gerätetypen

Während das Android Open Source-Projekt bei der Implementierung verschiedener Gerätetypen und Formfaktoren verwendet wurde, wurden viele Aspekte der Architektur und Kompatibilitätsanforderungen für Handheld-Geräte optimiert. Ab Android 5.0 zielt das Android Open Source-Projekt darauf ab, eine größere Vielfalt an Gerätetypen abzudecken, wie in diesem Abschnitt beschrieben.

Android-Handgerät bezieht sich auf eine Android-Geräteimplementierung, die normalerweise in der Hand gehalten wird, z. B. MP3-Player, Telefone und Tablets. Implementierungen von Android-Handheld-Geräten:

• Im Gerät MUSS ein Touchscreen integriert sein.
• MUSS über eine Stromquelle verfügen, die Mobilität gewährleistet, beispielsweise eine Batterie.

Android Television-Gerät bezieht sich auf eine Android-Geräteimplementierung, die eine Unterhaltungsschnittstelle zum Konsumieren digitaler Medien, Filme, Spiele, Apps und/oder Live-TV für Benutzer darstellt, die etwa drei Meter entfernt sitzen (eine „zurückgelehnte“ oder „10-Fuß-Benutzeroberfläche“) “). Android-Fernsehgeräte:

• MUSS über einen eingebetteten Bildschirm verfügen ODER über einen Videoausgangsanschluss wie VGA, HDMI oder einen drahtlosen Anschluss für die Anzeige verfügen.
• MÜSSEN die Funktionen android.software.leanback und android.hardware.type.television deklarieren.

Android Watch-Gerät bezieht sich auf eine Android-Geräteimplementierung, die dazu gedacht ist, am Körper, möglicherweise am Handgelenk, getragen zu werden, und:

• MUSS über einen Bildschirm mit einer physischen Diagonallänge im Bereich von 1,1 bis 2,5 Zoll verfügen.
• MUSS die Funktion android.hardware.type.watch deklarieren.
• MUSS uiMode = UI_MODE_TYPE_WATCH unterstützen.

Unter Android Automotive-Implementierung versteht man eine Fahrzeug-Headunit, auf der Android als Betriebssystem für einen Teil oder die gesamte System- und/oder Infotainment-Funktionalität läuft. Android Automotive-Implementierungen:

• MUSS über einen Bildschirm mit einer physischen Diagonallänge von mindestens 6 Zoll verfügen.
• MUSS die Funktion android.hardware.type.automotive deklarieren.
• MUSS uiMode = UI_MODE_TYPE_CAR unterstützen.
• Android Automotive-Implementierungen MÜSSEN alle öffentlichen APIs im Namespace android.car.* unterstützen.

Alle Android-Geräteimplementierungen, die nicht in einen der oben genannten Gerätetypen passen, MÜSSEN dennoch alle Anforderungen in diesem Dokument erfüllen, um mit Android 7.1 kompatibel zu sein, es sei denn, die Anforderung wird ausdrücklich so beschrieben, dass sie nur für einen bestimmten Android-Gerätetyp von oben gilt.

2.1 Gerätekonfigurationen

Dies ist eine Zusammenfassung der wichtigsten Unterschiede in der Hardwarekonfiguration nach Gerätetyp. (Leere Zellen kennzeichnen ein „MAY“). In dieser Tabelle werden nicht alle Konfigurationen abgedeckt. Weitere Einzelheiten finden Sie in den entsprechenden Abschnitten zur Hardware.

3. Software

3.1. Verwaltete API-Kompatibilität

Die verwaltete Dalvik-Bytecode-Ausführungsumgebung ist das primäre Vehikel für Android-Anwendungen. Die Android-Anwendungsprogrammierschnittstelle (API) ist der Satz von Android-Plattformschnittstellen, die Anwendungen zur Verfügung gestellt werden, die in der verwalteten Laufzeitumgebung ausgeführt werden. Geräteimplementierungen MÜSSEN vollständige Implementierungen, einschließlich aller dokumentierten Verhaltensweisen, aller dokumentierten APIs bereitstellen, die vom Android SDK bereitgestellt werden, oder aller APIs, die im Upstream-Android-Quellcode mit der Markierung „@SystemApi“ versehen sind.

Geräteimplementierungen MÜSSEN alle Klassen, Methoden und zugehörigen Elemente unterstützen/beibehalten, die durch die TestApi-Annotation (@TestApi) gekennzeichnet sind.

Geräteimplementierungen DÜRFEN KEINE verwalteten APIs auslassen, API-Schnittstellen oder Signaturen ändern, vom dokumentierten Verhalten abweichen oder No-Ops enthalten, es sei denn, dies ist in dieser Kompatibilitätsdefinition ausdrücklich zulässig.

Diese Kompatibilitätsdefinition erlaubt, dass einige Hardwaretypen, für die Android APIs enthält, bei Geräteimplementierungen weggelassen werden. In solchen Fällen MÜSSEN die APIs weiterhin vorhanden sein und sich angemessen verhalten. Spezifische Anforderungen für dieses Szenario finden Sie in Abschnitt 7 .

3.1.1. Android-Erweiterungen

Android bietet die Unterstützung für die Erweiterung der verwalteten APIs unter Beibehaltung der gleichen API-Level-Version. Android-Geräteimplementierungen MÜSSEN die AOSP-Implementierung sowohl der gemeinsam genutzten Bibliothek ExtShared als auch der Dienste ExtServices mit Versionen vorladen, die höher oder gleich den pro API-Ebene zulässigen Mindestversionen sind. Beispielsweise MÜSSEN Android 7.0-Geräteimplementierungen mit API-Level 24 mindestens Version 1 enthalten.

3.2. Soft-API-Kompatibilität

Zusätzlich zu den verwalteten APIs aus Abschnitt 3.1 enthält Android auch eine bedeutende, nur zur Laufzeit verfügbare „weiche“ API in Form von Dingen wie Absichten, Berechtigungen und ähnlichen Aspekten von Android-Anwendungen, die beim Kompilieren der Anwendung nicht erzwungen werden können.

3.2.1. Berechtigungen

Geräteimplementierer MÜSSEN alle Berechtigungskonstanten unterstützen und durchsetzen, wie auf der Berechtigungsreferenzseite dokumentiert. Beachten Sie, dass in Abschnitt 9 zusätzliche Anforderungen im Zusammenhang mit dem Android-Sicherheitsmodell aufgeführt sind.

3.2.2. Build-Parameter

Die Android-APIs enthalten eine Reihe von Konstanten in der Klasse android.os.Build , die das aktuelle Gerät beschreiben sollen. Um konsistente, aussagekräftige Werte über alle Geräteimplementierungen hinweg bereitzustellen, enthält die folgende Tabelle zusätzliche Einschränkungen für die Formate dieser Werte, denen Geräteimplementierungen entsprechen MÜSSEN.

3.2.3. Absichtskompatibilität

3.2.3.1. Kernanwendungsabsichten

Mithilfe von Android-Absichten können Anwendungskomponenten Funktionen von anderen Android-Komponenten anfordern. Das Android-Upstream-Projekt enthält eine Liste von Anwendungen, die als Kernanwendungen von Android gelten, und implementiert mehrere Absichtsmuster zum Ausführen allgemeiner Aktionen. Die wichtigsten Android-Anwendungen sind:

• Tischuhr
• Browser
• Kalender
• Kontakte
• Galerie
• GlobalSearch
• Startprogramm
• Musik
• Einstellungen

Geräteimplementierungen MÜSSEN gegebenenfalls die Android-Kernanwendungen oder eine Komponente enthalten, die dieselben Absichtsmuster implementiert, die von allen Aktivitäts- oder Dienstkomponenten dieser Android-Kernanwendungen definiert werden, die implizit oder explizit über das Attribut android:exported andere Anwendungen verfügbar gemacht werden.

3.2.3.2. Absichtsauflösung

Da Android eine erweiterbare Plattform ist, MÜSSEN Geräteimplementierungen zulassen, dass jedes in Abschnitt 3.2.3.1 genannte Absichtsmuster durch Anwendungen von Drittanbietern überschrieben wird. Die Upstream-Android-Open-Source-Implementierung ermöglicht dies standardmäßig; Geräteimplementierer DÜRFEN KEINE besonderen Privilegien für die Verwendung dieser Absichtsmuster durch Systemanwendungen festlegen oder verhindern, dass Anwendungen Dritter sich an diese Muster binden und die Kontrolle über sie übernehmen. Dieses Verbot umfasst insbesondere die Deaktivierung der „Chooser“-Benutzeroberfläche, die es dem Benutzer ermöglicht, zwischen mehreren Anwendungen auszuwählen, die alle dasselbe Absichtsmuster verarbeiten.

Geräteimplementierungen MÜSSEN eine Benutzeroberfläche bereitstellen, über die Benutzer die Standardaktivität für Absichten ändern können.

Geräteimplementierungen stellen jedoch möglicherweise Standardaktivitäten für bestimmte URI-Muster bereit (z. B. http://play.google.com), wenn die Standardaktivität ein spezifischeres Attribut für den Daten-URI bereitstellt. Beispielsweise ist ein Absichtsfiltermuster, das den Daten-URI „http://www.android.com“ angibt, spezifischer als das Kernabsichtsmuster des Browsers für „http://“.

Android enthält außerdem einen Mechanismus für Drittanbieter-Apps, um ein verbindliches Standard- App-Verknüpfungsverhalten für bestimmte Arten von Web-URI-Absichten zu deklarieren. Wenn solche maßgeblichen Deklarationen in den Absichtsfiltermustern einer App definiert sind, führen Geräteimplementierungen Folgendes aus:

• MUSS versuchen, alle Absichtsfilter zu validieren, indem die Validierungsschritte ausgeführt werden, die in der Digital Asset Links-Spezifikation definiert sind und vom Paketmanager im Upstream-Android-Open-Source-Projekt implementiert werden.
• MÜSSEN während der Installation der Anwendung versuchen, die Absichtsfilter zu validieren, und alle erfolgreich validierten UIR-Absichtsfilter als Standard-App-Handler für ihre UIRs festlegen.
• KÖNNEN bestimmte URI-Absichtsfilter als Standard-App-Handler für ihre URIs festlegen, wenn sie erfolgreich überprüft werden, andere URI-Kandidatenfilter jedoch die Überprüfung nicht bestehen. Wenn eine Geräteimplementierung dies tut, MUSS sie dem Benutzer im Einstellungsmenü entsprechende URI-Musterüberschreibungen bereitstellen.
• Dem Benutzer MÜSSEN App-Link-Steuerelemente pro App in den Einstellungen wie folgt zur Verfügung gestellt werden:
  • Der Benutzer MUSS in der Lage sein, das standardmäßige App-Link-Verhalten einer App ganzheitlich zu überschreiben: immer offen, immer fragen oder nie öffnen, was für alle möglichen URI-Intent-Filter gleichermaßen gelten muss.
  • Der Benutzer MUSS eine Liste der möglichen URI-Intent-Filter sehen können.
  • Die Geräteimplementierung bietet dem Benutzer möglicherweise die Möglichkeit, bestimmte erfolgreich verifizierte Kandidaten-URI-Intent-Filter pro Intent-Filter zu überschreiben.
  • Die Geräteimplementierung MUSS Benutzern die Möglichkeit bieten, bestimmte Kandidaten-URI-Intent-Filter anzuzeigen und zu überschreiben, wenn die Geräteimplementierung zulässt, dass einige Kandidaten-URI-Intent-Filter die Überprüfung erfolgreich durchführen, während andere fehlschlagen können.

3.2.3.3. Absichts-Namespaces

Geräteimplementierungen DÜRFEN KEINE Android-Komponenten enthalten, die neue Absichten oder Broadcast-Intent-Muster mithilfe einer ACTION, CATEGORY oder einer anderen Schlüsselzeichenfolge im Android berücksichtigen. oder com.android. Namensraum. Geräteimplementierer DÜRFEN KEINE Android-Komponenten einschließen, die neue Absichten oder Broadcast-Absichtsmuster mithilfe einer ACTION, CATEGORY oder einer anderen Schlüsselzeichenfolge in einem Paketbereich berücksichtigen, der einer anderen Organisation gehört. Geräteimplementierer DÜRFEN KEINE Absichtsmuster ändern oder erweitern, die von den in Abschnitt 3.2.3.1 aufgeführten Kern-Apps verwendet werden. Geräteimplementierungen KÖNNEN Absichtsmuster enthalten, die Namespaces verwenden, die eindeutig und offensichtlich mit ihrer eigenen Organisation verknüpft sind. Dieses Verbot ist analog zu dem für Java-Sprachklassen in Abschnitt 3.6 genannten.

3.2.3.4. Sendeabsichten

Anwendungen von Drittanbietern verlassen sich darauf, dass die Plattform bestimmte Absichten sendet, um sie über Änderungen in der Hardware- oder Softwareumgebung zu informieren. Android-kompatible Geräte MÜSSEN die öffentlichen Sendeabsichten als Reaktion auf entsprechende Systemereignisse übertragen. Broadcast-Absichten werden in der SDK-Dokumentation beschrieben.

3.2.3.5. Standard-App-Einstellungen

Android verfügt über Einstellungen, die Benutzern eine einfache Möglichkeit bieten, ihre Standardanwendungen auszuwählen, beispielsweise für den Startbildschirm oder SMS. Wo es sinnvoll ist, MÜSSEN Geräteimplementierungen ein ähnliches Einstellungsmenü bereitstellen und mit dem Intent-Filtermuster und den API-Methoden kompatibel sein, die in der SDK-Dokumentation unten beschrieben sind.

Geräteimplementierungen:

• MUSS die Absicht von android.settings.HOME_SETTINGS berücksichtigen, ein Standard-App-Einstellungsmenü für den Startbildschirm anzuzeigen, wenn die Geräteimplementierung android.software.home_screen meldet.
• MUSS ein Einstellungsmenü bereitstellen, das die Absicht android.provider.Telephony.ACTION_CHANGE_DEFAULT aufruft, um einen Dialog zum Ändern der Standard-SMS-Anwendung anzuzeigen, wenn die Geräteimplementierung android.hardware.telephony meldet.
• MUSS die Absicht von android.settings.NFC_PAYMENT_SETTINGS berücksichtigen, ein Standard-App-Einstellungsmenü für Tap and Pay anzuzeigen, wenn die Geräteimplementierung android.hardware.nfc.hce meldet.
• MUSS die Absicht von android.telecom.action.CHANGE_DEFAULT_DIALER berücksichtigen, um einen Dialog anzuzeigen, der es dem Benutzer ermöglicht, die Standard-Telefonanwendung zu ändern, wenn die Geräteimplementierung android.hardware.telephony meldet.
• MUSS die Absicht android.settings.ACTION_VOICE_INPUT_SETTINGS berücksichtigen, wenn das Gerät den VoiceInteractionService unterstützt und ein Standard-App-Einstellungsmenü für Spracheingabe und -unterstützung anzeigt.

3.3. Native API-Kompatibilität

Die Kompatibilität mit nativem Code ist eine Herausforderung. Aus diesem Grund wird Geräteimplementierern DRINGEND EMPFOHLEN , die Implementierungen der unten aufgeführten Bibliotheken aus dem Upstream-Android-Open-Source-Projekt zu verwenden.

3.3.1. Binäre Anwendungsschnittstellen

Der verwaltete Dalvik-Bytecode kann nativen Code aufrufen, der in der APK-Datei der Anwendung als ELF-SO-Datei bereitgestellt wird, die für die entsprechende Hardwarearchitektur des Geräts kompiliert wurde. Da nativer Code stark von der zugrunde liegenden Prozessortechnologie abhängt, definiert Android im Android NDK eine Reihe von Application Binary Interfaces (ABIs). Geräteimplementierungen MÜSSEN mit einem oder mehreren definierten ABIs kompatibel sein und MÜSSEN die Kompatibilität mit dem Android NDK implementieren, wie unten beschrieben.

Wenn eine Geräteimplementierung Unterstützung für eine Android-ABI umfasst, gilt Folgendes:

• MUSS Unterstützung für Code enthalten, der in der verwalteten Umgebung ausgeführt wird, um nativen Code unter Verwendung der standardmäßigen JNI-Semantik (Java Native Interface) aufzurufen.
• MUSS mit jeder erforderlichen Bibliothek in der Liste unten quellkompatibel (dh Header-kompatibel) und binärkompatibel (für das ABI) sein.
• MUSS das entsprechende 32-Bit-ABI unterstützen, wenn ein 64-Bit-ABI unterstützt wird.
• MUSS die vom Gerät unterstützte native Application Binary Interface (ABI) über die Parameter android.os.Build.SUPPORTED_ABIS, android.os.Build.SUPPORTED_32_BIT_ABIS und android.os.Build.SUPPORTED_64_BIT_ABIS genau angeben, jeweils eine durch Kommas getrennte Liste von ABIs, geordnet vom am meisten bevorzugten zum am wenigsten bevorzugten.
• MÜSSEN über die oben genannten Parameter nur die ABIs melden, die in der neuesten Version der Android NDK ABI Management-Dokumentation dokumentiert und beschrieben sind, und MÜSSEN Unterstützung für die Advanced SIMD- Erweiterung (auch bekannt als NEON) enthalten.
• SOLLTE unter Verwendung des Quellcodes und der Header-Dateien erstellt werden, die im Upstream-Android-Open-Source-Projekt verfügbar sind

Beachten Sie, dass zukünftige Versionen des Android NDK möglicherweise Unterstützung für zusätzliche ABIs einführen. Wenn eine Geräteimplementierung nicht mit einem vorhandenen vordefinierten ABI kompatibel ist, DARF sie überhaupt keine Unterstützung für ABIs melden.

Die folgenden nativen Code-APIs MÜSSEN für Apps verfügbar sein, die nativen Code enthalten:

• libandroid.so (native Android-Aktivitätsunterstützung)
• libc (C-Bibliothek)
• libcamera2ndk.so
• libdl (dynamischer Linker)
• libEGL.so (native OpenGL-Oberflächenverwaltung)
• libGLESv1_CM.so (OpenGL ES 1.x)
• libGLESv2.so (OpenGL ES 2.0)
• libGLESv3.so (OpenGL ES 3.x)
• libicui18n.so
• libicuuc.so
• libjnigraphics.so
• liblog (Android-Protokollierung)
• libmediandk.so (Unterstützung nativer Medien-APIs)
• libm (Mathebibliothek)
• libOpenMAXAL.so (OpenMAX AL 1.0.1-Unterstützung)
• libOpenSLES.so (OpenSL ES 1.0.1 Audiounterstützung)
• libRS.so
• libstdc++ (Minimale Unterstützung für C++)
• libvulkan.so (Vulkan)
• libz (Zlib-Komprimierung)
• JNI-Schnittstelle
• Unterstützung für OpenGL, wie unten beschrieben

Für die oben aufgeführten nativen Bibliotheken DARF die Geräteimplementierung die öffentlichen Funktionen NICHT hinzufügen oder entfernen.

Native Bibliotheken, die oben nicht aufgeführt sind, aber in AOSP als Systembibliotheken implementiert und bereitgestellt werden, sind reserviert und DÜRFEN NICHT für Apps von Drittanbietern verfügbar gemacht werden, die auf API-Level 24 oder höher abzielen.

Geräteimplementierungen KÖNNEN Nicht-AOSP-Bibliotheken hinzufügen und sie direkt als API für Apps von Drittanbietern verfügbar machen, aber die zusätzlichen Bibliotheken SOLLTEN sich in /vendor/lib oder /vendor/lib64 befinden und MÜSSEN in /vendor/etc/public.libraries.txt .

Beachten Sie, dass Geräteimplementierungen libGLESv3.so enthalten MÜSSEN und wiederum alle OpenGL ES 3.1- und Android Extension Pack- Funktionssymbole exportieren MÜSSEN, wie in der NDK-Version Android-24 definiert. Obwohl alle Symbole vorhanden sein müssen, müssen nur die entsprechenden Funktionen für tatsächlich vom Gerät unterstützte OpenGL ES-Versionen und Erweiterungen vollständig implementiert sein.

3.3.1.1. Grafikbibliotheken

Vulkan ist eine plattformübergreifende API mit geringem Overhead für leistungsstarke 3D-Grafiken. Geräteimplementierungen MÜSSEN die folgenden Anforderungen erfüllen, auch wenn sie keine Unterstützung der Vulkan-APIs enthalten:

• Es MUSS immer eine native Bibliothek namens libvulkan.so bereitstellen, die Funktionssymbole für die Vulkan 1.0-Kern-API sowie die Erweiterungen VK_KHR_surface , VK_KHR_android_surface und VK_KHR_swapchain exportiert.

Geräteimplementierungen, sofern Unterstützung der Vulkan-APIs enthalten:

• MUSS ein oder mehrere VkPhysicalDevices über den vkEnumeratePhysicalDevices Aufruf melden.
• Jedes aufgelistete VkPhysicalDevices MUSS die Vulkan 1.0-API vollständig implementieren.
• MÜSSEN die korrekten Feature-Flags PackageManager#FEATURE_VULKAN_HARDWARE_LEVEL und PackageManager#FEATURE_VULKAN_HARDWARE_VERSION melden.
• MÜSSEN Schichten, die in nativen Bibliotheken mit dem Namen libVkLayer*.so im nativen Bibliotheksverzeichnis des Anwendungspakets enthalten sind, über die Funktionen vkEnumerateInstanceLayerProperties und vkEnumerateDeviceLayerProperties in libvulkan.so aufzählen
• DÜRFEN NICHT Schichten auflisten, die von Bibliotheken außerhalb des Anwendungspakets bereitgestellt werden, oder andere Möglichkeiten zum Verfolgen oder Abfangen der Vulkan-API bereitstellen, es sei denn, die Anwendung verfügt über das Attribut android:debuggable=”true” .

Geräteimplementierungen, sofern keine Unterstützung der Vulkan-APIs enthalten:

• MUSS 0 VkPhysicalDevices über den vkEnumeratePhysicalDevices Aufruf melden.
• DARF KEINE der Vulkan-Feature-Flags PackageManager#FEATURE_VULKAN_HARDWARE_LEVEL und PackageManager#FEATURE_VULKAN_HARDWARE_VERSION deklariert werden.

3.3.2. Kompatibilität mit nativem 32-Bit-ARM-Code

Die ARMv8-Architektur veraltet mehrere CPU-Vorgänge, einschließlich einiger Vorgänge, die in vorhandenem nativem Code verwendet werden. Auf 64-Bit-ARM-Geräten MÜSSEN die folgenden veralteten Vorgänge für nativen 32-Bit-ARM-Code verfügbar bleiben, entweder durch native CPU-Unterstützung oder durch Software-Emulation:

• SWP- und SWPB-Anweisungen
• SETEND-Anweisung
• CP15ISB-, CP15DSB- und CP15DMB-Barriereoperationen

Ältere Versionen des Android NDK verwendeten /proc/cpuinfo, um CPU-Funktionen aus nativem 32-Bit-ARM-Code zu ermitteln. Aus Gründen der Kompatibilität mit Anwendungen, die mit diesem NDK erstellt wurden, MÜSSEN Geräte die folgenden Zeilen in /proc/cpuinfo enthalten, wenn sie von 32-Bit-ARM-Anwendungen gelesen werden:

• „Features:“, gefolgt von einer Liste aller optionalen ARMv7-CPU-Funktionen, die vom Gerät unterstützt werden.
• „CPU-Architektur:“, gefolgt von einer Ganzzahl, die die höchste unterstützte ARM-Architektur des Geräts beschreibt (z. B. „8“ für ARMv8-Geräte).

Diese Anforderungen gelten nur, wenn /proc/cpuinfo von 32-Bit-ARM-Anwendungen gelesen wird. Geräte sollten /proc/cpuinfo nicht ändern, wenn sie von 64-Bit-ARM- oder Nicht-ARM-Anwendungen gelesen werden.

3.4. Webkompatibilität

3.4.1. WebView-Kompatibilität

Die Plattformfunktion android.software.webview MUSS auf jedem Gerät gemeldet werden, das eine vollständige Implementierung der android.webkit.WebView-API bereitstellt, und DARF NICHT auf Geräten ohne vollständige Implementierung der API gemeldet werden. Die Android Open Source-Implementierung verwendet Code aus dem Chromium-Projekt, um android.webkit.WebView zu implementieren. Da es nicht möglich ist, eine umfassende Testsuite für ein Web-Rendering-System zu entwickeln, MÜSSEN Geräteimplementierer den spezifischen Upstream-Build von Chromium in der WebView-Implementierung verwenden. Speziell:

• Geräteimplementierungen von android.webkit.WebView MÜSSEN auf dem Chromium- Build aus dem Upstream-Android-Open-Source-Projekt für Android 7.1 basieren. Dieser Build enthält einen bestimmten Satz an Funktionen und Sicherheitskorrekturen für WebView.

• Die von WebView gemeldete Benutzeragentenzeichenfolge MUSS in diesem Format vorliegen:

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

  • Der Wert der Zeichenfolge $(VERSION) MUSS mit dem Wert für android.os.Build.VERSION.RELEASE identisch sein.
  • Der Wert der $ (Modell) String muss dem Wert für Android.os.build.model übereinstimmen.
  • Der Wert der $ (Build) -Sache muss dem Wert für android.os.build.id übereinstimmen.
  • Der Wert der $ (chromium_ver) -Sache muss die Version von Chrom im vorgelagerten Android Open Source -Projekt sein.
  • Geräteimplementierungen können Mobilgeräte in der Benutzeragentenzeichenfolge auslassen.

Die WebView -Komponente sollte Unterstützung für möglichst viele HTML5 -Funktionen wie möglich enthalten. Wenn sie unterstützt, sollte die Funktion der HTML5 -Spezifikation entsprechen.

3.4.2. Browser-Kompatibilität

Der eigenständige Browser basiert möglicherweise auf einer anderen Browser -Technologie als Webkit. Selbst wenn eine alternative Browseranwendung verwendet wird, muss die in Abschnitt 3.4 .

Implementierungen können eine benutzerdefinierte Benutzeragenten -Zeichenfolge in der eigenständigen Browseranwendung versenden.

Die eigenständige Browseranwendung (unabhängig davon, ob sie auf der vorgelagerten Webkit-Browseranwendung oder einem Ersatz von Drittanbietern basieren) sollte die Unterstützung für möglichst viel HTML5 enthalten. Minimal müssen Geräteimplementierungen jede dieser APIs unterstützen, die mit HTML5 verbunden sind:

• Anwendungs ​​-Cache/Offline -Betrieb
• <video> Tag
• Geolokalisierung

Darüber hinaus müssen Geräteimplementierungen die HTML5/W3C -Webstorage -API unterstützen und die HTML5/W3C IndexedDB -API unterstützen. Beachten Sie, dass die Körpers für Webentwicklungsstandards in einer zukünftigen Version von Android zu einer erforderlichen Komponente werden, wenn die Körper für Webentwicklungsstandards umgehen, um IndexedDB gegenüber Webstorage zu bevorzugen.

3.5. API -Verhaltenskompatibilität

Das Verhalten der einzelnen API -Typen (verwaltet, weich, nativ und web) muss mit der bevorzugten Implementierung des vorgelagerten Android -Open -Source -Projekts übereinstimmen. Einige spezifische Kompatibilitätsbereiche sind:

• Geräte dürfen das Verhalten oder die Semantik einer Standardabsicht nicht ändern.
• Geräte dürfen die Lebenszyklus- oder Lebenszyklus -Semantik einer bestimmten Systemkomponente (wie Service, Aktivität, ContentProvider usw.) nicht verändern.
• Geräte dürfen die Semantik einer Standardgenehmigung nicht ändern.

Die obige Liste ist nicht umfassend. Die CTS -Kompatibilitätstest -Suite (CTS) testet signifikante Teile der Plattform auf Verhaltenskompatibilität, jedoch nicht alle. Es liegt in der Verantwortung des Implementierers, die Verhaltenskompatibilität mit dem Android Open Source -Projekt sicherzustellen. Aus diesem Grund sollten Geräteimplementierer den Quellcode verwenden, der über das Android Open-Source-Projekt verfügbar ist, wo möglich, anstatt signifikante Teile des Systems erneut zu implementieren.

3.6. API -Namespaces

Android folgt den von der Java -Programmiersprache definierten Paket- und Klassennamespace -Konventionen. Um die Kompatibilität mit Anwendungen von Drittanbietern zu gewährleisten, dürfen Geräteimplementierer diese Paket-Namespaces nicht verboten (siehe unten):

• Java.*
• Javax.*
• Sonne.*
• Android.*
• com.android.*

Verbotene Modifikationen umfassen :

• Geräteimplementierungen dürfen die öffentlich freigelegten APIs auf der Android -Plattform nicht durch Ändern einer Methode oder Klassensignaturen oder durch Entfernen von Klassen oder Klassenfeldern ändern.
• Geräteimplementierer können die zugrunde liegende Implementierung der APIs ändern, aber solche Änderungen dürfen sich nicht auf das angegebene Verhalten und die Java-Sprache-Signatur einer öffentlich freigelegten APIs auswirken.
• Geräteimplementierer dürfen den oben genannten APIs keine öffentlich freiliegenden Elemente (wie Klassen oder Schnittstellen oder Felder oder Methoden zu den vorhandenen Klassen oder Schnittstellen) hinzufügen.

Ein "öffentlich exponiertes Element" ist ein Konstrukt, das nicht mit dem "@Hide" -Marker dekoriert ist, wie im vorgelagerten Android -Quellcode verwendet. Mit anderen Worten, Geräteimplementierer dürfen keine neuen APIs aufdecken oder vorhandene APIs in den oben angegebenen Namespaces ändern. Geräteimplementierer können nur interne Änderungen vornehmen, diese Änderungen dürfen jedoch nicht den Entwicklern beworben oder auf andere Weise ausgesetzt werden.

Geräteimplementierer können benutzerdefinierte APIs hinzufügen, aber jede solche APIs dürfen nicht in einem Namespace enthalten sein oder sich auf eine andere Organisation beziehen. Beispielsweise dürfen Geräteimplementierer dem com.google keine APIs hinzufügen.* Oder einen ähnlichen Namespace: Nur Google kann dies tun. In ähnlicher Weise darf Google den Namespaces anderer Unternehmen keine APIs hinzufügen. Wenn eine Geräteimplementierung außerhalb des Standard-Android-Namespace benutzerdefinierte APIs enthält von solchen Apis.

Wenn ein Geräteimplementierer vorschlägt, einen der oben genannten Paketnamenspaces zu verbessern ( z . Code nach den Informationen auf dieser Website.

Beachten Sie, dass die obigen Beschränkungen Standardkonventionen für die Benennung von APIs in der Java -Programmiersprache entsprechen. Dieser Abschnitt zielt lediglich darauf ab, diese Konventionen zu verstärken und sie durch Einbeziehung in diese Kompatibilitätsdefinition zu verbinden.

3.7. Laufzeitkompatibilität

Geräteimplementierungen müssen das vollständige Dalvik Executable (DEX) -Format und die Dalvik -Bytecode -Spezifikation und die Semantik unterstützen. Geräteimplementierer sollten ART, die Referenz -Upstream -Implementierung des ausführbaren Dalvik -Formates und das Paketverwaltungssystem der Referenzimplementierung verwenden.

Geräteimplementierungen müssen Dalvik Runtimes so konfigurieren, dass Speicher gemäß der vorgelagerten Android -Plattform und gemäß der folgenden Tabelle angegeben ist. (Siehe Abschnitt 7.1.1 für Bildschirmgröße und Bildschirmdichtedefinitionen.) Beachten Sie, dass die unten angegebenen Speicherwerte als Mindestwerte berücksichtigt werden, und Geräteimplementierungen können mehr Speicher pro Anwendung zuweisen.

3.8. Benutzeroberfläche Kompatibilität

3.8.1. Launcher (Startbildschirm)

Android umfasst eine Launcher-Anwendung (Startbildschirm) und die Unterstützung von Anwendungen von Drittanbietern, um den Gerätewerfer (Startbildschirm) zu ersetzen. Geräteimplementierungen, mit denen Drittanbieter-Anwendungen den Startbildschirm des Geräts ersetzen können, müssen die Plattformfunktion Android.software.Home_Screen deklarieren.

3.8.2. Widgets

Android definiert einen Komponententyp und entsprechenden API und Lebenszyklus, mit dem Anwendungen dem Endbenutzer ein „AppWidget“ vorlegen können, eine Funktion, die dringend empfohlen wird, bei Handheld -Geräteimplementierungen unterstützt zu werden. Geräteimplementierungen, die die Einbettung von Widgets auf den Startbildschirm unterstützen, müssen die folgenden Anforderungen erfüllen und die Unterstützung für die Plattformfunktion Android.software.app_widgets erklären.

• Gerätestarger müssen integrierte Unterstützung für AppWidgets enthalten und die Benutzeroberfläche zum Hinzufügen, Konfigurieren, Ansehen und Entfernen von AppWidgets direkt im Launcher enthüllen.
• Die Geräteimplementierungen müssen in der Lage sein, Widgets mit 4 x 4 in der Standardgittergröße zu rendern. Einzelheiten finden Sie in den Richtlinien für die App -Widget -Design -Richtlinien in der Dokumentation von Android SDK.
• Geräteimplementierungen, die die Unterstützung für den Sperrbildschirm enthalten, können Anwendungs ​​-Widgets auf dem Sperrbildschirm unterstützen.

3.8.3. Benachrichtigungen

Android enthält APIs, mit denen Entwickler Benutzer mithilfe von Hardware- und Softwarefunktionen des Geräts über bemerkenswerte Ereignisse informieren können.

Einige APIs ermöglichen es Anwendungen, Benachrichtigungen durchzuführen oder die Aufmerksamkeit mit Hardware zu erregen - spezifisch solide, vibration und Licht. Geräteimplementierungen müssen Benachrichtigungen unterstützen, die Hardwarefunktionen verwenden, wie in der SDK -Dokumentation beschrieben, und soweit möglich, die Hardware für Geräteimplementierung möglich ist. Wenn beispielsweise eine Geräteimplementierung einen Vibrator enthält, muss die Vibrations -APIs korrekt implementiert werden. Wenn eine Geräteimplementierung keine Hardware hat, müssen die entsprechenden APIs als No-OPS implementiert werden. Dieses Verhalten wird in Abschnitt 7 weiter beschrieben.

Darüber hinaus muss die Implementierung alle Ressourcen (Symbole, Animationsdateien usw.) korrekt in den APIs oder im Status/System -Balken -Symbolstil -Leitfaden rendern, die im Fall eines Android -Fernsehgeräts die Möglichkeit enthält, die nicht anzuzeigen Benachrichtigungen. Geräteimplementierer bieten möglicherweise eine alternative Benutzererfahrung für Benachrichtigungen als die durch die Referenz -Open -Source -Implementierung von Referenz. Solche alternativen Benachrichtigungssysteme müssen jedoch wie oben oben bestehende Benachrichtigungsressourcen unterstützen.

Android beinhaltet Unterstützung für verschiedene Benachrichtigungen, wie zum Beispiel:

• Reiche Benachrichtigungen . Interaktive Ansichten für laufende Benachrichtigungen.
• Heads-up-Benachrichtigungen . Interaktive Ansichten können Benutzer handeln oder entlassen, ohne die aktuelle App zu verlassen.
• Sperrbildschirm Benachrichtigungen . Benachrichtigungen, die über einem Sperrbildschirm mit körniger Steuerung bei der Sichtbarkeit angezeigt werden.

Implementierungen für Android-Geräte, wenn solche Benachrichtigungen sichtbar werden, müssen ordnungsgemäß reiche und Heads-up-Benachrichtigungen ausführen und den in der Android-API dokumentierten Titel/Namen, Symbol, Text enthalten.

Android enthält APIs für Benachrichtigungslistener -Service, mit denen Apps (sobald der Benutzer explizit aktiviert ist) eine Kopie aller Benachrichtigungen erhalten, sobald sie veröffentlicht oder aktualisiert werden. Die Geräteimplementierungen müssen in vollem Umfang benachrichtigte Benachrichtigungen in vollem Umfang an alle diese installierten und benutzerfähigen Hörerdienste senden, einschließlich aller Metadaten, die dem Benachrichtigungsobjekt angehängt sind.

Handheld -Geräteimplementierungen müssen das Verhalten der Aktualisierung, Entfernen, Beantwortung und Bündelung von Benachrichtigungen unterstützen, wie in diesem Abschnitt beschrieben.

Außerdem müssen Handheld -Geräteimplementierungen angeben:

• Die Fähigkeit, Benachrichtigungen direkt im Benachrichtigungsschatten zu steuern.
• Die visuelle Gewährung, um das Bedienfeld im Benachrichtigungsschatten auszulösen.
• Die Möglichkeit, die Benachrichtigungspräferenz aus einem Paket zu blockieren, stumm zu sein und zurückzusetzen, sowohl im Inline -Bedienfeld als auch in der Einstellungs -App.

Alle 6 direkten Unterklassen der Notification.Style class müssen wie in den SDK -Dokumenten beschrieben unterstützt werden.

Geräteimplementierungen, die die DND -Funktion (nicht stören) unterstützen, müssen die folgenden Anforderungen erfüllen:

• Muss eine Aktivität implementieren, die auf die Absicht reagieren würde action_notification_policy_access_Setingss , die für Implementierungen mit UI_MODE_TYPE_NORMAL eine Aktivität sein muss, bei der der Benutzer den App -Zugriff auf DND -Richtlinienkonfigurationen gewähren oder verweigern kann.
• Muss, wenn die Geräteimplementierung dem Benutzer ein Mittel zur Verfügung gestellt hat, um Apps von Drittanbietern zu gewähren oder zu verweigern, um auf die Konfiguration der DND-Richtlinie zugreifen zu können, automatische DND-Regeln angezeigt, die von Anwendungen zusammen mit den vom Benutzer erstellten und vordefinierten Regeln erstellt wurden.
• Muss die suppressedVisualEffects -Werte ehren, die an der NotificationManager.Policy übergeben wurden. Wenn eine App die unterdrückten Flags unterdrückte_effect_screen_off oder unterdrückte_effect_screen_on festgelegt hat, sollte es dem Benutzer angezeigt, dass die visuellen Effekte im Menü der DND -Einstellungen unterdrückt werden.

3.8.4. Suchen

Android enthält APIs, mit denen Entwickler die Suche in ihre Anwendungen einbeziehen und die Daten ihrer Anwendung in die globale Systemsuche aufnehmen können. Im Allgemeinen besteht diese Funktionalität aus einer einzelnen systemweiten Benutzeroberfläche, mit der Benutzer Abfragen eingeben, Vorschläge als Typ Benutzer anzeigen und die Ergebnisse anzeigen. Die Android -APIs ermöglichen es Entwicklern, diese Schnittstelle wiederzuverwenden, um die Suche in ihren eigenen Apps bereitzustellen und den Entwicklern der gemeinsamen globalen Suchbenutzeroberfläche Ergebnisse zu liefern.

Die Implementierungen von Android-Geräten sollten eine globale Suche, eine einzelne, gemeinsam genutzte, systemweite Suchbenutzeroberfläche enthalten, die Echtzeitvorschläge als Reaktion auf die Benutzereingabe in der Lage ist. Geräteimplementierungen sollten die APIs implementieren, mit denen Entwickler diese Benutzeroberfläche wiederverwenden können, um die Suche in ihren eigenen Anwendungen anzubieten. Geräteimplementierungen, die die globale Suchschnittstelle implementieren, müssen die APIs implementieren, mit denen Drittanbieter Anwendungen dem Suchfeld beim Ausführen im globalen Suchmodus Vorschläge hinzufügen können. Wenn keine Anwendungen von Drittanbietern installiert sind, die diese Funktionalität nutzen, sollte das Standardverhalten darin bestehen, die Ergebnisse und Vorschläge für Web-Suchmaschinen anzuzeigen.

Implementierungen von Android -Geräten sollten und Android Automotive -Implementierungen einen Assistenten auf dem Gerät implementieren, um die Assist -Aktion zu verarbeiten.

Android enthält auch die Assist -APIs , um die Anwendungen zu ermöglichen, wie viele Informationen über den aktuellen Kontext an den Assistenten auf dem Gerät gemeinsam genutzt werden. Geräteimplementierungen, die die Assist -Aktion unterstützen, müssen dem Endbenutzer deutlich angeben, wenn der Kontext geteilt wird, indem ein weißes Licht an den Rändern des Bildschirms angezeigt wird. Um dem Endbenutzer eine klare Sichtbarkeit zu gewährleisten, muss die Anzeige die Dauer und Helligkeit der Implementierung von Android Open Source -Projekt erfüllen oder übertreffen.

Diese Anzeige kann standardmäßig für vorinstallierte Apps mithilfe der API Assist und VoiceInteractionService deaktiviert werden, wenn alle folgenden Anforderungen erfüllt sind:

• Die vorinstallierte App muss anfordern, dass der Kontext nur dann freigegeben wird, wenn der Benutzer die App mit einem der folgenden Mittel aufgerufen hat und die App im Vordergrund ausgeführt wird:

  • Hotword -Aufruf
  • Eingabe des Assist Navigationstasts/Taste/Geste

• Die Geräteimplementierung muss eine Gewährleistung bieten, um die Anzeige zu ermöglichen, weniger als zwei Navigationen von (dem Menü "Standard -Spracheingabe- und Assistenten -App -Einstellungen) Abschnitt 3.2.3.5 .

3.8.5. Toasts

Anwendungen können die API „Toast“ verwenden, um dem Endbenutzer kurze nicht modale Zeichenfolgen anzuzeigen, die nach kurzer Zeit verschwinden. Geräteimplementierungen müssen Toast von Anwendungen auf Endbenutzer in einer gewissen Sichtbarkeit anzeigen.

3.8.6. Themen

Android bietet „Themen“ als Mechanismus für Anwendungen, um Stile auf eine gesamte Aktivität oder Anwendung anzuwenden.

Android enthält eine „Holo“ -Mthem -Familie als eine Reihe definierter Stile für Anwendungsentwickler, die sie verwenden können, wenn sie das Holo -Thema aussehen möchten, wie sie vom Android SDK definiert sind. Geräteimplementierungen dürfen keine der Holo -Themenattribute ändern, die Anwendungen ausgesetzt sind.

Android enthält eine „materielle“ Themenfamilie als eine Reihe definierter Stile, die Anwendungsentwickler verwenden können, wenn sie das Aussehen und Gefühl des Designthemens über die Vielzahl verschiedener Android -Gerätetypen anpassen möchten. Geräteimplementierungen müssen die „materielle“ Themenfamilie unterstützen und dürfen keine der materiellen Themenattribute oder deren Vermögenswerte ändern, die Anwendungen ausgesetzt sind.

Android enthält außerdem eine „Geräte -Standard“ -Thema -Familie als eine Reihe definierter Stile für Anwendungsentwickler, die sie verwenden können, wenn sie das vom Geräteimplementierer definierte Gerätethema anpassen möchten. Geräteimplementierungen können die Geräte -Standard -Themenattribute ändern, die Anwendungen ausgesetzt sind.

Android unterstützt ein Variante -Thema mit durchscheinenden Systembalken, mit dem Anwendungsentwickler den Bereich hinter dem Status und der Navigationsleiste mit ihrem App -Inhalt füllen können. Um eine konsistente Entwicklererfahrung in dieser Konfiguration zu ermöglichen, ist es wichtig, dass der Status -Icon -Stil für verschiedene Geräteimplementierungen aufrechterhalten wird. Daher müssen Android -Geräteimplementierungen White für Systemstatus -Symbole (z. B. Signalstärke und Batteriestufe) und vom System ausgegebene Benachrichtigungen verwenden, es sei denn, das Symbol gibt einen problematischen Status an oder ein App fordert eine Lichtstatusleiste an, die das Flag von System_Ui_FLAG_LIGHT_STATUS_BAR mithilfe des Systems system_ui_flag_status_bar anfordert. Wenn eine App eine Lichtstatusleiste anfordert, müssen Android -Geräteimplementierungen die Farbe der Systemstatus -Symbole in Schwarz ändern (Einzelheiten finden Sie unter R.Style ).

3.8.7. Live-Hintergründe

Android definiert einen Komponententyp und entsprechenden API und Lebenszyklus, mit denen Anwendungen dem Endbenutzer einen oder mehrere „Live -Hintergrundbilder“ zur Verfügung stellen können. Live -Hintergrundbilder sind Animationen, Muster oder ähnliche Bilder mit begrenzten Eingangsfunktionen, die als Tapete hinter anderen Anwendungen angezeigt werden.

Hardware gilt als in der Lage, zuverlässig Live -Hintergrundbilder auszuführen, wenn sie alle Live -Hintergrundbilder ohne Einschränkungen bei der Funktionalität mit einer angemessenen Bildrate ohne nachteilige Auswirkungen auf andere Anwendungen ausführen kann. Wenn Einschränkungen in der Hardware -Hintergrundbilder und/oder Anwendungen zum Absturz, zu Fehlfunktionen, zu einer übermäßigen CPU- oder der Batteriestromversorgung oder bei unannehmbar niedrigen Bildraten ausgeführt werden, gilt die Hardware als unfähig, Live -Tapeten auszuführen. Beispielsweise können einige Live -Hintergrundbilder einen OpenGL 2.0- oder 3.x -Kontext verwenden, um ihren Inhalt zu rendern. Live Wallpaper läuft nicht zuverlässig auf Hardware, die mehrere OpenGL -Kontexte nicht unterstützt, da die Live -Wallpaper -Verwendung eines OpenGL -Kontextes möglicherweise mit anderen Anwendungen in Konflikt steht, die auch einen OpenGL -Kontext verwenden.

Geräteimplementierungen, mit denen Live -Hintergrundbilder wie oben beschrieben zuverlässig ausgeführt werden können, sollten Live -Hintergrundbilder implementieren und müssen bei der Implementierung das Plattform -Feature -Flag Android.software.live_wallpaper melden.

3.8.8. Aktivitätsumschaltung

Der vorgelagerte Android-Quellcode enthält den Übersichtsbildschirm , eine Benutzeroberfläche auf Systemebene für das Umschalten und die Anzeige kürzlich zugegriffener Aktivitäten und Aufgaben mit einem Miniaturbild des grafischen Status der Anwendung zum Zeitpunkt des letzten Verlaufs der Anwendung. Geräteimplementierungen einschließlich des in Abschnitt 7.2.3 detaillierten Funktionsfunktionsfunktionsfunktionsnavigationsschlüssels können die Schnittstelle ändern, müssen jedoch die folgenden Anforderungen erfüllen:

• Muss mindestens bis zu 20 angezeigte Aktivitäten unterstützen.
• Sollte zumindest den Titel von 4 Aktivitäten gleichzeitig anzeigen.
• Muss das Bildschirm -Pinning -Verhalten implementieren und dem Benutzer ein Einstellungsmenü zur Umstellung der Funktion zur Verfügung stellen.
• Sollte Highlight -Farb-, Symbol- und Bildschirm -Titel in den Rezenenten anzeigen.
• Sollte eine schließende Gewährung ("x") anzeigen, kann dies jedoch verzögern, bis der Benutzer mit Bildschirmen interagiert.
• Sollte eine Abkürzung implementieren, um einfach auf die vorherige Aktivität umzusteigen
• Kann angeschlossene Rezenden als Gruppe angezeigt, die sich miteinander bewegt.
• Sollte die schnelle Wirkung zwischen den beiden zuletzt verwendeten Apps auslösen, wenn der Funktionstaste der Recents zweimal angezapft wird.
• Sollte den Multiwindow-Modus mit Split-Screen-Modus auslösen, falls unterstützt, wenn die Taste der Recents-Funktionen lange gedrückt wird.

Geräteimplementierungen werden dringend empfohlen, um die vorgelagerte Android-Benutzeroberfläche (oder eine ähnliche Miniaturansicht-Schnittstelle) für den Übersichtsbildschirm zu verwenden.

3.8.9. Eingabeverwaltung

Android bietet Unterstützung für die Eingabeverwaltung und die Unterstützung für Eingabemethoden von Drittanbietern. Geräteimplementierungen, mit denen Benutzer Eingabemethoden von Drittanbietern auf dem Gerät verwenden können, müssen die Plattformfunktion Android.software.input_methods deklarieren und IME-APIs wie in der Android SDK-Dokumentation definiert.

Geräteimplementierungen, die die Funktion von Android.software deklarieren.input_Methods-Funktion, müssen einen benutzergerechten Mechanismus bereitstellen, um Eingabemethoden von Drittanbietern hinzuzufügen und zu konfigurieren. Geräteimplementierungen müssen die Einstellungsschnittstelle als Antwort auf die Absicht von Android.Setings.input_Method_Setings angezeigt.

3.8.10. Lock -Bildschirmmediensteuerung sperren

Die Remote Control Client -API ist von Android 5.0 zugunsten der Medienbenachrichtigungsvorlage veraltet, mit der Medienanwendungen in Wiedergabesteuerelemente integriert werden können, die auf dem Sperrbildschirm angezeigt werden. Geräteimplementierungen, die einen Sperrbildschirm unterstützen, es sei denn, eine Android -Automobil- oder Watch -Implementierung, müssen die Sperrbildschirmbenachrichtigungen einschließlich der Medienbenachrichtigungsvorlage anzeigen.

3.8.11. Bildschirmsparer (zuvor Träume)

Android beinhaltet Unterstützung für interaktive Creensavers , die zuvor als Träume bezeichnet werden. Mit Bildschirmsparern können Benutzer mit Anwendungen interagieren, wenn ein mit einer Stromquelle verbundener Gerät in einem Schreibtischdock im Leerlauf ist. Android Watch -Geräte können Bildschirmsparer implementieren. Andere Arten von Geräteimplementierungen sollten jedoch die Unterstützung für Bildschirmsparer enthalten und eine Einstellungsoption für Benutzer mit Bildschirmsparern als Reaktion auf die Intent android.settings.DREAM_SETTINGS bereitstellen.

3.8.12. Standort

Wenn ein Gerät über einen Hardwaresensor (z. B. GPS) verfügt, der die Standortkoordinaten bereitstellen kann, müssen Standortmodi im Standortmenü innerhalb der Einstellungen angezeigt werden.

3.8.13. Unicode und Schriftart

Android enthält Unterstützung für die in Unicode 9.0 definierten Emoji -Zeichen. Alle Geräteimplementierungen müssen in der Lage sein, diese Emoji -Zeichen in Farbglyphen zu rendern. Wenn Android -Geräteimplementierungen ein IME enthalten, sollte sie dem Benutzer eine Eingabemethode für diese Emoji -Zeichen bereitstellen.

Android Handheld -Geräte sollten den Hautton und die verschiedenen Familien -Emojis wie im technischen Bericht Nr. 51 von Unicode unterstützen.

Android beinhaltet die Unterstützung für Roboto 2-Schriftart mit unterschiedlichen Gewichten-serif-dünn, sans-serif-light, sans-serif-medium, sans-serif-schwarz, serif-kondensierter, serif-kondenziertes Licht-, in welch Muss alle für die auf dem Gerät verfügbaren Sprachen und die vollständige Unicode 7.0 -Abdeckung der lateinischen, griechischen und kyrillischen Abdeckung der lateinischen erweiterten A-, B-, C- und D -Bereiche sowie alle Glyphen im Währungssymbolblock von Unicode 7.0 enthalten sein.

3.8.14. Multi-Windows

Eine Geräteimplementierung kann sich dafür entscheiden, keine Multi-Window-Modi zu implementieren. Wenn sie jedoch in der Lage ist, mehrere Aktivitäten gleichzeitig anzuzeigen Der Android SDK Multi-Window-Modus unterstützt die Dokumentation und erfüllt die folgenden Anforderungen:

• Anwendungen können angeben, ob sie in der Datei AndroidManifest.xml im Multi-Window-Modus operieren können, entweder explizit über das android:resizeableActivity Nicht im Multi-Window-Modus gestartet werden. Apps, die das Attribut nicht in ihrer Manifestdatei festlegen (TargetsDkversion <24), können im Multi-Window-Modus gestartet werden. Das System muss jedoch Warnung geben, dass die App möglicherweise nicht wie im Multi-Window-Modus erwartet funktioniert.
• Geräteimplementierungen dürfen keinen Split-Screen- oder Freiformmodus anbieten, wenn sowohl die Bildschirmhöhe als auch die Breite von weniger als 440 dp beträgt.
• Geräteimplementierungen mit Bildschirmgröße xlarge sollten den Freiform -Modus unterstützen.
• Implementierungen für Android-Fernsehgeräte müssen den Multi-Window (PIP-Modus PIP-Modus "im Bild des Bildes unterstützen und die PIP-Multi-Window in die obere rechte Ecke platzieren, wenn PIP eingeschaltet ist.
• Geräteimplementierungen mit PIP-Modus Multi-Window-Unterstützung müssen für das PIP-Fenster mindestens 240 x 135 dp zuweisen.
• Wenn der PIP-Multi-Window-Modus unterstützt wird, muss der KeyEvent.KEYCODE_WINDOW Schlüssel verwendet werden, um das PIP-Fenster zu steuern. Andernfalls muss der Schlüssel für die Vordergrundaktivität zur Verfügung stehen.

3.9. Geräteverwaltung

Android enthält Funktionen, mit denen Sicherheitsanwendungen auf Systemebene, z. B. die Durchsetzung von Kennwortrichtlinien oder die Durchführung von Remote-Löschen, über die API Android Device Administration ermöglicht werden können. Geräteimplementierungen müssen eine Implementierung der DevicePolicyManager -Klasse bereitstellen. Geräteimplementierungen, die einen sicheren Sperrbildschirm unterstützen, müssen den gesamten Bereich der in der Android SDK -Dokumentation definierten Geräteverwaltungsrichtlinien implementieren und die Plattformfunktion Android.software.device_admin melden.

3.9.1 Gerätebereitstellung

3.9.1.1 Gerätebesitzer Bereitstellung

Wenn eine Geräteimplementierung die Funktion android.software.device_admin deklariert, muss die Bereitstellung der Geräte -Eigentümer -App einer DPC -Anwendung (Geräte -Richtlinie Client) wie unten angegeben implementiert:

• Wenn die Geräteimplementierung noch keine Benutzerdaten konfiguriert hat, ist dies:
  • MUSS true für DevicePolicyManager.isProvisioningAllowed(ACTION_PROVISION_MANAGED_DEVICE) .
  • Müssen Sie die DPC -Anwendung als Geräte -Eigentümer -App als Antwort auf die Intent -Aktion android.app.action.PROVISION_MANAGED_DEVICE anmelden.
  • Müssen Sie die DPC-Anwendung als Geräte-Eigentümer-App anmelden, wenn das Gerät in der Nahfeldkommunikation (NFC) über das Feature Flag android.hardware.nfc (NFC) unterstützt wird und eine NFC-Nachricht mit einem Datensatz mit MIME-Typ MIME_TYPE_PROVISIONING_NFC erhält.
• Wenn die Geräteimplementierung Benutzerdaten enthält, ist dies:
  • Muss false für den DevicePolicyManager.isProvisioningAllowed(ACTION_PROVISION_MANAGED_DEVICE) melden.
  • Darf keine DPC -Anwendung als Geräte -Eigentümer -App anmelden.

Geräteimplementierungen haben möglicherweise eine vorinstallierte Anwendung, die Geräteverwaltungsfunktionen ausführen. Diese Anwendung darf jedoch nicht ohne explizite Einwilligung oder Aktion des Benutzer oder des Administrators des Geräts als Geräte -Eigentümer -App festgelegt werden.

3.9.1.2 Managed Profile Provisioning

Wenn eine Geräteimplementierung die Android.software.Managed_Users erklärt, muss es möglich sein, eine DPC -Anwendung (Geräterichtlinie) als Eigentümer eines neuen verwalteten Profils anzumelden.

Der Benutzererlebnis von Android.App.Action.Provision_Managed_Profile muss sich mit der AOSP -Implementierung übereinstimmen.

Geräteimplementierungen müssen die folgenden Benutzerverdiener in der Benutzeroberfläche der Einstellungen bereitstellen, um dem Benutzer anzuzeigen, wenn eine bestimmte Systemfunktion vom Geräte -Richtlinien -Controller (DPC) deaktiviert wurde:

• Ein konsistentes Symbol oder ein anderes Benutzerverdiener (z. B. das vorgelagerte AOSP -Info -Symbol), um darzustellen, wenn eine bestimmte Einstellung durch einen Geräteadministrator eingeschränkt wird.
• Eine kurze Erläuterungsnachricht, die vom Geräteadministrator über die setShortSupportMessage bereitgestellt wird.
• Das Symbol der DPC -Anwendung.

3.9.2 Managed Profile Support

Managed Profile fähige Geräte sind die Geräte, die:

• Deklarieren Sie android.software.device_admin (siehe Abschnitt 3.9 Geräteverwaltung ).
• Sind keine niedrigen RAM -Geräte (siehe Abschnitt 7.6.1 ).
• Ziehen Sie den internen (nicht frequentierbaren) Speicher als freigegebener Speicher (siehe Abschnitt 7.6.2 ) aus.

Managed Profile fähige Geräte müssen:

• Deklarieren Sie die Plattform -Feature -Flagge android.software.managed_users .
• Support Managed Profile über die android.app.admin.DevicePolicyManager -APIs.
• Erstellen Sie ein und nur ein verwaltetes Profil .
• Verwenden Sie ein Symbolabzeichen (ähnlich wie das ASP -Upstream -Arbeitsabzeichen), um die verwalteten Anwendungen und Widgets und andere Bahnen -UI -Elemente wie Recents & Benachrichtigungen darzustellen.
• Zeigen Sie ein Benachrichtigungssymbol an (ähnlich dem ASP -Upstream -Arbeitsabzeichen), um anzugeben, wann der Benutzer in einer verwalteten Profilanwendung liegt.
• Zeigen Sie einen Toast an, der angibt, dass sich der Benutzer im verwalteten Profil befindet, wenn das Gerät aufwacht (action_user_present), und die Vordergrundanwendung befindet sich im verwalteten Profil.
• Wenn ein verwaltetes Profil vorhanden ist, zeigen Sie eine visuelle Gewährung in der Absicht 'Chooser', damit der Benutzer die Absicht vom verwalteten Profil an den primären Benutzer oder umgekehrt weiterleiten kann, falls vom Geräte -Richtlinien -Controller aktiviert wird.
• Wob
  • Separate Abrechnung für Batterie-, Standort-, Mobildaten- und Speicherverbrauch für das primäre Benutzer und das verwaltete Profil.
  • Unabhängige Verwaltung von VPN -Anwendungen, die im primären Benutzer oder im verwalteten Profil installiert sind.
  • Unabhängige Verwaltung von Anwendungen, die im primären Benutzer oder im verwalteten Profil installiert sind.
  • Unabhängige Verwaltung von Konten innerhalb des primären Benutzer- oder verwalteten Profils.
• Stellen Sie sicher, dass die vorinstallierten Dialer, Kontakte und Messaging -Anwendungen neben denen aus dem primären Profil nach den Anruferinformationen aus dem verwalteten Profil suchen und nachschlagen können, wenn der Geräterichtlinie -Controller dies zulässt. Wenn Kontakte aus dem verwalteten Profil im vorinstallierten Anrufprotokoll-, in-Call-UI-, in-progress- und fehlgeschlagene Benachrichtigungen, Kontakte und Messaging-Apps angezeigt werden, sollten sie mit demselben Abzeichen ausgewählt werden, das verwendet wird, um verwaltete Profilanwendungen anzuzeigen.
• Muss sicherstellen, dass alle Sicherheitsanforderungen für ein Gerät mit aktivierten Benutzern erfüllt werden (siehe Abschnitt 9.5 ), obwohl das verwaltete Profil zusätzlich zum primären Benutzer nicht als ein anderer Benutzer gezählt wird.
• Unterstützen Sie die Möglichkeit, ein separates Sperrbildschirm anzugeben Die folgenden Anforderungen, um Zugriff auf Apps zu ermöglichen, die in einem verwalteten Profil ausgeführt werden.
  • Geräteimplementierungen müssen den DevicePolicyManager.ACTION_SET_NEW_PASSWORD ehren
  • Die Sperrbildschirmanmeldeinformationen des verwalteten Profils müssen dieselben Anmeldeinformationen Speicher- und Verwaltungsmechanismen wie das übergeordnete Profil verwenden, wie auf der Android Open Source -Projektstelle dokumentiert
  • Die DPC -Kennwortrichtlinien müssen nur für die Sperrbildschirmanmeldungen des verwalteten Profils gelten, sofern die von GetParentProfileinstance zurückgegebene DevicePolicyManager -Instanz aufgerufen wird.

3.10. Barrierefreiheit

Android bietet eine Barrierefreiheitschicht, mit der Benutzer mit Behinderungen einfacher navigieren können. Darüber hinaus bietet Android Plattform-APIs, mit denen Barrierefreiheit-Service-Implementierungen für Benutzer- und Systemereignisse empfangen und alternative Feedback-Mechanismen wie Text-to-Speech, Haptic Feedback und Trackball/D-Pad-Navigation generiert werden können.

Die Geräteimplementierungen enthalten die folgenden Anforderungen:

• Android Automotive -Implementierungen sollten eine Implementierung des Android -Barrierefreiheits -Frameworks für die Standard -Android -Implementierung bereitstellen.
• Geräteimplementierungen (Android Automotive ausgeschlossen) müssen eine Implementierung des Android -Barrierefreiheits -Frameworks bereitstellen, das mit der Standard -Android -Implementierung übereinstimmt.
• Geräteimplementierungen (Android Automotive ausgeschlossen) müssen Implementierungen von Barrierefreiheit von Drittanbietern über die APIs von Android.AccessibilityService unterstützen.
• Device implementations (Android Automotive excluded) MUST generate AccessibilityEvents and deliver these events to all registered AccessibilityService implementations in a manner consistent with the default Android implementation

• Device implementations (Android Automotive and Android Watch devices with no audio output excluded), MUST provide a user-accessible mechanism to enable and disable accessibility services, and MUST display this interface in response to the android.provider.Settings.ACTION_ACCESSIBILITY_SETTINGS intent.

• Android device implementations with audio output are STRONGLY RECOMMENDED to provide implementations of accessibility services on the device comparable in or exceeding functionality of the TalkBack** and Switch Access accessibility services (https://github.com/google/talkback).

• Android Watch devices with audio output SHOULD provide implementations of an accessibility service on the device comparable in or exceeding functionality of the TalkBack accessibility service (https://github.com/google/talkback).
• Device implementations SHOULD provide a mechanism in the out-of-box setup flow for users to enable relevant accessibility services, as well as options to adjust the font size, display size and magnification gestures.

** For languages supported by Text-to-speech.

Also, note that if there is a preloaded accessibility service, it MUST be a Direct Boot aware {directBootAware} app if the device has encrypted storage using File Based Encryption (FBE).

3.11. Text zu Sprache

Android includes APIs that allow applications to make use of text-to-speech (TTS) services and allows service providers to provide implementations of TTS services. Device implementations reporting the feature android.hardware.audio.output MUST meet these requirements related to the Android TTS framework .

Android Automotive implementations:

• MUST support the Android TTS framework APIs.
• MAY support installation of third-party TTS engines. If supported, partners MUST provide a user-accessible interface that allows the user to select a TTS engine for use at system level.

All other device implementations:

• MUST support the Android TTS framework APIs and SHOULD include a TTS engine supporting the languages available on the device. Note that the upstream Android open source software includes a full-featured TTS engine implementation.
• MUST support installation of third-party TTS engines.
• MUST provide a user-accessible interface that allows users to select a TTS engine for use at the system level.

3.12. TV Input Framework

The Android Television Input Framework (TIF) simplifies the delivery of live content to Android Television devices. TIF provides a standard API to create input modules that control Android Television devices. Android Television device implementations MUST support TV Input Framework.

Device implementations that support TIF MUST declare the platform feature android.software.live_tv.

3.12.1. TV-App

Any device implementation that declares support for Live TV MUST have an installed TV application (TV App). The Android Open Source Project provides an implementation of the TV App.

The TV App MUST provide facilities to install and use TV Channels and meet the following requirements:

• Device implementations MUST allow third-party TIF-based inputs ( third-party inputs ) to be installed and managed.
• Device implementations MAY provide visual separation between pre-installed TIF-based inputs (installed inputs) and third-party inputs.
• Device implementations MUST NOT display the third-party inputs more than a single navigation action away from the TV App (ie expanding a list of third-party inputs from the TV App).

3.12.1.1. Electronic Program Guide

Android Television device implementations MUST show an informational and interactive overlay, which MUST include an electronic program guide (EPG) generated from the values in the TvContract.Programs fields. The EPG MUST meet the following requirements:

• The EPG MUST display information from all installed inputs and third-party inputs.
• The EPG MAY provide visual separation between the installed inputs and third-party inputs.
• The EPG is STRONGLY RECOMMENDED to display installed inputs and third-party inputs with equal prominence. The EPG MUST NOT display the third-party inputs more than a single navigation action away from the installed inputs on the EPG.
• On channel change, device implementations MUST display EPG data for the currently playing program.

3.12.1.2. Navigation

The TV App MUST allow navigation for the following functions via the D-pad, Back, and Home keys on the Android Television device's input device(s) (ie remote control, remote control application, or game controller):

• Changing TV channels
• Opening EPG
• Configuring and tuning to third-party TIF-based inputs
• Opening Settings menu

The TV App SHOULD pass key events to HDMI inputs through CEC.

3.12.1.3. TV input app linking

Android Television device implementations MUST support TV input app linking , which allows all inputs to provide activity links from the current activity to another activity (ie a link from live programming to related content). The TV App MUST show TV input app linking when it is provided.

3.12.1.4. Zeitverschiebung

Android Television device implementations MUST support time shifting, which allows the user to pause and resume live content. Device implementations MUST provide the user a way to pause and resume the currently playing program, if time shifting for that program is available .

3.12.1.5. TV recording

Android Television device implementations are STRONGLY RECOMMENDED to support TV recording. If the TV input supports recording, the EPG MAY provide a way to record a program if the recording of such a program is not prohibited . Device implementations SHOULD provide a user interface to play recorded programs.

3.13. Schnelleinstellungen

Android device implementations SHOULD include a Quick Settings UI component that allow quick access to frequently used or urgently needed actions.

Android includes the quicksettings API allowing third party apps to implement tiles that can be added by the user alongside the system-provided tiles in the Quick Settings UI component. If a device implementation has a Quick Settings UI component, it:

• MUST allow the user to add or remove tiles from a third-party app to Quick Settings.
• MUST NOT automatically add a tile from a third-party app directly to Quick Settings.
• MUST display all the user-added tiles from third-party apps alongside the system-provided quick setting tiles.

3.14. Vehicle UI APIs

3.14.1. Vehicle Media UI

Any device implementation that declares automotive support MUST include a UI framework to support third-party apps consuming the MediaBrowser and MediaSession APIs.

The UI framework supporting third-party apps that depend on MediaBrowser and MediaSession has the following visual requirements:

• MUST display MediaItem icons and notification icons unaltered.
• MUST display those items as described by MediaSession, eg, metadata, icons, imagery.
• MUST show app title.
• MUST have drawer to present MediaBrowser hierarchy.

4. Application Packaging Compatibility

Device implementations MUST install and run Android “.apk” files as generated by the “aapt” tool included in the official Android SDK . For this reason device implementations SHOULD use the reference implementation's package management system.

The package manager MUST support verifying “.apk” files using the APK Signature Scheme v2 and JAR signing .

Devices implementations MUST NOT extend either the .apk , Android Manifest , Dalvik bytecode , or RenderScript bytecode formats in such a way that would prevent those files from installing and running correctly on other compatible devices.

Device implementations MUST NOT allow apps other than the current "installer of record" for the package to silently uninstall the app without any prompt, as documented in the SDK for the DELETE_PACKAGE permission. The only exceptions are the system package verifier app handling PACKAGE_NEEDS_VERIFICATION intent and the storage manager app handling ACTION_MANAGE_STORAGE intent.

5. Multimedia Compatibility

5.1. Media Codecs

Device implementations—

• MUST support the core media formats specified in the Android SDK documentation, except where explicitly permitted in this document.

• MUST support the media formats, encoders, decoders, file types, and container formats defined in the tables below and reported via MediaCodecList .

• MUST also be able to decode all profiles reported in its CamcorderProfile

• MUST be able to decode all formats it can encode. This includes all bitstreams that its encoders generate.

Codecs SHOULD aim for minimum codec latency, in other words, codecs—

• SHOULD NOT consume and store input buffers and return input buffers only once processed
• SHOULD NOT hold onto decoded buffers for longer than as specified by the standard (eg SPS).
• SHOULD NOT hold onto encoded buffers longer than required by the GOP structure.

All of the codecs listed in the table below are provided as software implementations in the preferred Android implementation from the Android Open Source Project.

Please note that neither Google nor the Open Handset Alliance make any representation that these codecs are free from third-party patents. Those intending to use this source code in hardware or software products are advised that implementations of this code, including in open source software or shareware, may require patent licenses from the relevant patent holders.

5.1.1. Audio-Codecs

1 Required for device implementations that define android.hardware.microphone but optional for Android Watch device implementations.

2 Recording or playback MAY be performed in mono or stereo, but the decoding of AAC input buffers of multichannel streams (ie more than two channels) to PCM through the default AAC audio decoder in the android.media.MediaCodec API, the following MUST be supported:

• decoding is performed without downmixing (eg a 5.0 AAC stream must be decoded to five channels of PCM, a 5.1 AAC stream must be decoded to six channels of PCM),
• dynamic range metadata, as defined in "Dynamic Range Control (DRC)" in ISO/IEC 14496-3, and the android.media.MediaFormat DRC keys to configure the dynamic range-related behaviors of the audio decoder. The AAC DRC keys were introduced in API 21,and are: KEY_AAC_DRC_ATTENUATION_FACTOR, KEY_AAC_DRC_BOOST_FACTOR, KEY_AAC_DRC_HEAVY_COMPRESSION, KEY_AAC_DRC_TARGET_REFERENCE_LEVEL and KEY_AAC_ENCODED_TARGET_LEVEL

3 Required for Android Handheld device implementations.

4 Required for device implementations that define android.hardware.microphone, including Android Watch device implementations.

5.1.2. Image Codecs

5.1.3. Video-Codecs

• Codecs advertising HDR profile support MUST support HDR static metadata parsing and handling.

• If a media codec advertises intra refresh support, then it MUST support the refresh periods in the range of 10 - 60 frames and accurately operate within 20% of configured refresh period.

• Video codecs MUST support output and input bytebuffer sizes that accommodate the largest feasible compressed and uncompressed frame as dictated by the standard and configuration but also not overallocate.

• Video encoders and decoders MUST support YUV420 flexible color format (COLOR_FormatYUV420Flexible).

1 Required for device implementations that include camera hardware and define android.hardware.camera or android.hardware.camera.front.

2 Required for device implementations except Android Watch devices.

3 For acceptable quality of web video streaming and video-conference services, device implementations SHOULD use a hardware VP8 codec that meets the requirements .

4 Device implementations SHOULD support writing Matroska WebM files.

5 STRONGLY RECOMMENDED for Android Automotive, optional for Android Watch, and required for all other device types.

6 Applies only to Android Television device implementations.

5.2. Video Encoding

H.264, VP8, VP9 and HEVC video encoders—

• MUST support dynamically configurable bitrates.
• SHOULD support variable frame rates, where video encoder SHOULD determine instantaneous frame duration based on the timestamps of input buffers, and allocate its bit bucket based on that frame duration.

H.263 and MPEG-4 video encoder SHOULD support dynamically configurable bitrates.

All video encoders SHOULD meet the following bitrate targets over two sliding windows:

• It SHOULD be not more than ~15% over the bitrate between intraframe (I-frame) intervals.
• It SHOULD be not more than ~100% over the bitrate over a sliding window of 1 second.

5.2.1. H.263

Android device implementations with H.263 encoders MUST support Baseline Profile Level 45.

5.2.2. H-264

Android device implementations with H.264 codec support:

• MUST support Baseline Profile Level 3.
  However, support for ASO (Arbitrary Slice Ordering), FMO (Flexible Macroblock Ordering) and RS (Redundant Slices) is OPTIONAL. Moreover, to maintain compatibility with other Android devices, it is RECOMMENDED that ASO, FMO and RS are not used for Baseline Profile by encoders.
• MUST support the SD (Standard Definition) video encoding profiles in the following table.
• SHOULD support Main Profile Level 4.
• SHOULD support the HD (High Definition) video encoding profiles as indicated in the following table.
• In addition, Android Television devices are STRONGLY RECOMMENDED to encode HD 1080p video at 30 fps.

1 When supported by hardware, but STRONGLY RECOMMENDED for Android Television devices.

5.2.3. VP8

Android device implementations with VP8 codec support MUST support the SD video encoding profiles and SHOULD support the following HD (High Definition) video encoding profiles.

1 When supported by hardware.

5.3. Video Decoding

Device implementations—

• MUST support dynamic video resolution and frame rate switching through the standard Android APIs within the same stream for all VP8, VP9, H.264, and H.265 codecs in real time and up to the maximum resolution supported by each codec on the device.

• Implementations that support the Dolby Vision decoder—

• MUST provide a Dolby Vision-capable extractor.

• MUST properly display Dolby Vision content on the device screen or on a standard video output port (eg, HDMI).

• Implementations that provide a Dolby Vision-capable extractor MUST set the track index of backward-compatible base-layer(s) (if present) to be the same as the combined Dolby Vision layer's track index.

5.3.1. MPEG-2

Android device implementations with MPEG-2 decoders must support the Main Profile High Level.

5.3.2. H.263

Android device implementations with H.263 decoders MUST support Baseline Profile Level 30 and Level 45.

5.3.3. MPEG-4

Android device implementations with MPEG-4 decoders MUST support Simple Profile Level 3.

5.3.4. H.264

Android device implementations with H.264 decoders:

• MUST support Main Profile Level 3.1 and Baseline Profile.
  Support for ASO (Arbitrary Slice Ordering), FMO (Flexible Macroblock Ordering) and RS (Redundant Slices) is OPTIONAL.
• MUST be capable of decoding videos with the SD (Standard Definition) profiles listed in the following table and encoded with the Baseline Profile and Main Profile Level 3.1 (including 720p30).
• SHOULD be capable of decoding videos with the HD (High Definition) profiles as indicated in the following table.
• In addition, Android Television devices—
  • MUST support High Profile Level 4.2 and the HD 1080p60 decoding profile.
  • MUST be capable of decoding videos with both HD profiles as indicated in the following table and encoded with either the Baseline Profile, Main Profile, or the High Profile Level 4.2

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

2 REQUIRED for Android Television device implementations.

5.3.5. H.265 (HEVC)

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 SD video decoding profiles as indicated in the following table.
• SHOULD support the HD decoding profiles as indicated in the following table.
• MUST support the HD decoding profiles as indicated in the following table if there is a hardware decoder.
• In addition, Android Television devices:
• MUST support the HD 720p decoding profile.
• STRONGLY RECOMMENDED to support the HD 1080p decoding profile. If the HD 1080p decoding profile is supported, it MUST support the Main Profile Level 4.1 Main tier.
• SHOULD support the UHD decoding profile. If the UHD decoding profile is supported the codec MUST support Main10 Level 5 Main Tier profile.

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

5.3.6. VP8

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

• MUST support the SD decoding profiles in the following table.
• SHOULD support the HD decoding profiles in the following table.
• Android Television devices MUST support the HD 1080p60 decoding profile.

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

2 REQUIRED for Android Television device implementations.

5.3.7. VP9

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

• MUST support the SD video decoding profiles as indicated in the following table.
• SHOULD support the HD decoding profiles as indicated in the following table.
• MUST support the HD decoding profiles as indicated in the following table, if there is a hardware decoder.

• In addition, Android Television devices:

  • MUST support the HD 720p decoding profile.
  • STRONGLY RECOMMENDED to support the HD 1080p decoding profile.
  • SHOULD support the UHD decoding profile. If the UHD video decoding profile is supported, it MUST support 8-bit color depth and SHOULD support VP9 Profile 2 (10-bit).

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

5.4. Audio Aufnahme

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

5.4.1. Raw Audio Capture

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

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

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

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

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

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

5.4.2. Capture for Voice Recognition

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

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

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

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

5.4.3. Capture for Rerouting of Playback

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

• STREAM_RING
• STREAM_ALARM
• STREAM_NOTIFICATION

5.5. Audiowiedergabe

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

5.5.1. Raw Audio Playback

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

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

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

• Sampling rates : 24000, 48000

5.5.2. Audio Effects

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

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

5.5.3. Audio Output Volume

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

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

5.6. Audio Latency

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

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

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

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

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

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

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

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

5.7. Network Protocols

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

• HTTP(S) progressive streaming
  All required codecs and container formats in section 5.1 MUST be supported over HTTP(S)

• HTTP Live Streaming draft protocol, Version 7
  The following media segment formats MUST be supported:

• RTSP (RTP, SDP)

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

5.8. Secure Media

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

5.9. Musical Instrument Digital Interface (MIDI)

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

The MIDI-capable hardware transports are:

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

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

5.10. Professionelles Audio

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

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

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

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

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

5.11. Capture for Unprocessed

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

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

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

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

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

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

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

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

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

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

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

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

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

6. Developer Tools and Options Compatibility

6.1. Entwicklerwerkzeuge

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

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

6.2. Entwickleroptionen

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

7. Hardware Compatibility

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

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

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

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

7.1. Display and Graphics

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

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

• physical diagonal size . The distance in inches between two opposing corners of the illuminated portion of the display.
• dots per inch (dpi) . The number of pixels encompassed by a linear horizontal or vertical span of 1”. Where dpi values are listed, both horizontal and vertical dpi must fall within the range.
• Seitenverhältnis . 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. Bildschirmgröße

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

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

Zusätzlich:

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

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

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

7.1.1.2. Screen Aspect Ratio

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

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

7.1.1.3. Screen Density

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

• 120 dpi (ldpi)
• 160 dpi (mdpi)
• 213 dpi (tvdpi)
• 240 dpi (hdpi)
• 260 dpi (260dpi)
• 280 dpi (280dpi)
• 300 dpi (300dpi)
• 320 dpi (xhdpi)
• 340 dpi (340dpi)
• 360 dpi (360dpi)
• 400 dpi (400dpi)
• 420 dpi (420dpi)
• 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.

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

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

7.1.2. Display Metrics

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

7.1.3. Bildschirmausrichtung

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

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

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

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

7.1.4. 2D and 3D Graphics Acceleration

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

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

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

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

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

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

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

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

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

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

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

7.1.5. Legacy Application Compatibility Mode

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

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

7.1.6. Screen Technology

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

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

7.1.7. Secondary Displays

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

7.2. Eingabegeräte

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

7.2.1. Tastatur

Device implementations:

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

7.2.2. Non-touch Navigation

Device implementations:

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

7.2.3. Navigation Keys

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

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

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

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

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

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

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

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

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

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

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

7.2.4. Touchscreen Input

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

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

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

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

7.2.5. Fake Touch Input

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

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

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

7.2.6. Game Controller Support

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

7.2.6.1. Button Mappings

Android Television device implementations MUST support the following key mappings:

1 KeyEvent

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

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

4 MotionEvent

1 MotionEvent

7.2.7. Fernbedienung

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

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

7.3. Sensoren

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

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

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

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

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

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. Accelerometer

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

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

7.3.2. Magnetometer

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

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

7.3.3. GPS

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

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

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

7.3.4. Gyroskop

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

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

7.3.5. Barometer

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

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

7.3.6. Thermometer

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

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

7.3.7. Photometer

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

7.3.8. Näherungssensor

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

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

7.3.9. High Fidelity Sensors

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

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

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

• SENSOR_TYPE_GYROSCOPE

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

• SENSOR_TYPE_GYROSCOPE_UNCALIBRATED with the same quality requirements as SENSOR_TYPE_GYROSCOPE.

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

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

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

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

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

• SENSOR_TYPE_PROXIMITY: 100 sensor events

7.3.10. Fingerabdruck Sensor

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

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

7.3.11. Android Automotive-only sensors

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

7.3.11.1. Current Gear

Android Automotive implementations SHOULD provide current gear as SENSOR_TYPE_GEAR.

7.3.11.2. Day Night Mode

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

7.3.11.3. Driving Status

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

7.3.11.4. Wheel Speed

Android Automotive implementations MUST provide vehicle speed defined as SENSOR_TYPE_CAR_SPEED.

7.3.12. Pose Sensor

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

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

7.4. Datenkonnektivität

7.4.1. Telefonie

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

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

7.4.1.1. Number Blocking Compatibility

Android Telephony device implementations MUST include number blocking support and:

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

7.4.2. IEEE 802.11 (Wi-Fi)

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

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

7.4.2.1. Wi-Fi Direct

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

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

7.4.2.2. Wi-Fi Tunneled Direct Link Setup

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

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

7.4.3. Bluetooth

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

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

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

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

Device implementations including support for Bluetooth Low Energy:

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

7.4.4. Nahfeldkommunikation

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

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

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

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

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

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

• MUST report the android.hardware.nfc.hcef feature constant.
• MUST implement the NfcF Card Emulation APIs as defined in the Android SDK.

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

• MIFARE Classic
• MIFARE Ultralight
• NDEF on MIFARE Classic

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

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

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

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

7.4.5. Minimum Network Capability

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

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

Devices MAY implement more than one form of data connectivity.

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

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

IPv6 MUST be enabled by default.

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

IPv6 connectivity MUST be maintained in doze mode.

7.4.6. Synchronisierungseinstellungen

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

7.4.7. Data Saver

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

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

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

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

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

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

• MUST not broadcast ConnectivityManager.ACTION_RESTRICT_BACKGROUND_CHANGED

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

7.5. Kameras

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

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

7.5.1. Nach hinten gerichtete Kamera

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-Kamera

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

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

7.5.3. External Camera

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

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

7.5.4. Camera API Behavior

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

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

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

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

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

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

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

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

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

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

7.5.5. Camera Orientation

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

7.6. Memory and Storage

7.6.1. Minimum Memory and Storage

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

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

7.6.2. Application Shared Storage

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

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

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

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

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

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

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

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

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

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

7.6.3. Adoptable Storage

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

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

7.7. USB

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

7.7.1. USB peripheral mode

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

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

7.7.2. USB host mode

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

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

7.8. Audio

7.8.1. Mikrofon

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

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

7.8.2. Audioausgang

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

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

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

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

7.8.2.1. Analog Audio Ports

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

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

7.8.3. Near-Ultrasound

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

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

7.9. Virtuelle Realität

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

7.9.1. Virtual Reality Mode

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

7.9.2. Virtual Reality High Performance

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

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

8. Performance and Power

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

8.1. User Experience Consistency

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

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

8.2. File I/O Access Performance

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

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

8.3. Power-Saving Modes

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

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

8.4. Power Consumption Accounting

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

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

8.5. Consistent Performance

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

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

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

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

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

9. Security Model Compatibility

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

9.1. Berechtigungen

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

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

Permissions with a protection level of dangerous are runtime permissions. Applications with targetSdkVersion > 22 request them at runtime. Device implementations:

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

9.2. UID and Process Isolation

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

9.3. Filesystem Permissions

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

9.4. Alternate Execution Environments

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

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

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

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

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

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

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

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

9.5. Multi-User Support

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

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

9.6. Premium SMS Warning

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

9.7. Kernel Security Features

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

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

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

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

Device implementations:

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

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

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

9.8. Privatsphäre

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

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

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

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

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

9.9. Data Storage Encryption

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

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

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

9.9.1. Direct Boot

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

9.9.2. File Based Encryption

Device implementations supporting FBE:

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

The keys protecting CE and DE storage areas:

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

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

9.9.3. Full Disk Encryption

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

9.10. Device Integrity

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

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

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

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

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

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

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

9.11. Keys and Credentials

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

All Android device implementations MUST meet the following requirements:

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

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

9.11.1. Secure Lock Screen

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

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

9.12. Datenlöschung

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

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

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

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

9.13. Safe Boot Mode

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

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

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

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

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

9.14. Automotive Vehicle System Isolation

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

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

10. Software Compatibility Testing

Device implementations MUST pass all tests described in this section.

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

10.1. Kompatibilitätstestsuite

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

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

10.2. CTS Verifier

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

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

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

11. Updatable Software

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

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

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

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

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

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

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

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

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

12. Document Changelog

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

• Document changelog

For a summary of changes to individuals sections:

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

12.1. Changelog Viewing Tips

Changes are marked as follows:

• CDD
  Substantive changes to the compatibility requirements.

• Dokumente
  Cosmetic or build related changes.

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

13. Contact Us

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