Définition de compatibilité Android 2.3

Copyright © 2010, Google Inc. Tous droits réservés.
compatibilité@android.com

Table des matières

1. Introduction

Ce document énumère les exigences qui doivent être remplies pour que les téléphones mobiles soient compatibles avec Android 2.3.

L'utilisation de "doit", "ne doit pas", "requis", "doit", "ne doit pas", "devrait", "ne devrait pas", "recommandé", "peut" et "facultatif" est conforme à la norme IETF défini dans RFC2119 [ Ressources, 1 ].

Tel qu'utilisé dans ce document, un « implémenteur de périphérique » ou « implémenteur » est une personne ou une organisation développant une solution matérielle/logicielle exécutant Android 2.3. Une "implémentation de dispositif" ou "implémentation" est la solution matérielle/logicielle ainsi développée.

Pour être considérées comme compatibles avec Android 2.3, les implémentations d'appareils DOIVENT répondre aux exigences présentées dans cette définition de compatibilité, y compris tous les documents incorporés par référence.

Lorsque cette définition ou les tests logiciels décrits à la section 10 sont muets, ambigus ou incomplets, il incombe à l'implémenteur de l'appareil d'assurer la compatibilité avec les implémentations existantes. Pour cette raison, le projet Open Source Android [ Ressources, 3 ] est à la fois la référence et l'implémentation préférée d'Android. Les implémenteurs d'appareils sont fortement encouragés à baser leurs implémentations dans la mesure du possible sur le code source "en amont" disponible à partir du projet Open Source Android. Bien que certains composants puissent hypothétiquement être remplacés par des implémentations alternatives, cette pratique est fortement déconseillée, car la réussite des tests logiciels deviendra beaucoup plus difficile. Il est de la responsabilité de l'implémenteur d'assurer une compatibilité comportementale totale avec l'implémentation Android standard, y compris et au-delà de la suite de tests de compatibilité. Enfin, notez que certaines substitutions et modifications de composants sont explicitement interdites par ce document.

Veuillez noter que cette définition de compatibilité est publiée pour correspondre à la mise à jour 2.3.3 d'Android, qui correspond au niveau d'API 10. Cette définition rend obsolète et remplace la définition de compatibilité pour les versions Android 2.3 antérieures à 2.3.3. (C'est-à-dire que les versions 2.3.1 et 2.3.2 sont obsolètes.) Les futurs appareils compatibles Android exécutant Android 2.3 DOIVENT être livrés avec la version 2.3.3 ou ultérieure.

2. Ressources

1. Niveaux d'exigence IETF RFC2119 : http://www.ietf.org/rfc/rfc2119.txt
2. Présentation du programme de compatibilité Android : http://source.android.com/compatibility/index.html
3. Projet Open Source Android : http://source.android.com/
4. Définitions et documentation de l'API : http://developer.android.com/reference/packages.html
5. Référence des autorisations Android : http://developer.android.com/reference/android/Manifest.permission.html
6. Référence android.os.Build : http://developer.android.com/reference/android/os/Build.html
7. Chaînes de version autorisées pour Android 2.3 : http://source.android.com/compatibility/2.3/versions.html
8. Classe android.webkit.WebView : http://developer.android.com/reference/android/webkit/WebView.html
9. HTML5 : http://www.whatwg.org/specs/web-apps/current-work/multipage/
10. Fonctionnalités hors ligne HTML5 : http://dev.w3.org/html5/spec/Overview.html#offline
11. Balise vidéo HTML5 : http://dev.w3.org/html5/spec/Overview.html#video
12. API de géolocalisation HTML5/W3C : http://www.w3.org/TR/geolocation-API/
13. API de base de données Web HTML5/W3C : http://www.w3.org/TR/webdatabase/
14. API HTML5/W3C IndexedDB : http://www.w3.org/TR/IndexedDB/
15. Spécification Dalvik Virtual Machine : disponible dans le code source Android, sur dalvik/docs
16. Widgets d'application : http://developer.android.com/guide/practices/ui_guidelines/widget_design.html
17. Notifications : http://developer.android.com/guide/topics/ui/notifiers/notifications.html
18. Ressources d'application : http://code.google.com/android/reference/available-resources.html
19. Guide de style des icônes de la barre d'état : http://developer.android.com/guide/practices/ui_guideline/icon_design.html#statusbarstructure
20. Gestionnaire de recherche : http://developer.android.com/reference/android/app/SearchManager.html
21. Toast : http://developer.android.com/reference/android/widget/Toast.html
22. Fonds d'écran animés : https://android-developers.googleblog.com/2010/02/live-wallpapers.html
23. Documentation de l'outil de référence (pour adb, aapt, ddms) : http://developer.android.com/guide/developing/tools/index.html
24. Description du fichier apk Android : http://developer.android.com/guide/topics/fundamentals.html
25. Fichiers manifestes : http://developer.android.com/guide/topics/manifest/manifest-intro.html
26. Outil de test de singe : https://developer.android.com/studio/test/other-testing-tools/monkey
27. Liste des fonctionnalités du matériel Android : http://developer.android.com/reference/android/content/pm/PackageManager.html
28. Prise en charge de plusieurs écrans : http://developer.android.com/guide/practices/screens_support.html
29. android.util.DisplayMetrics : http://developer.android.com/reference/android/util/DisplayMetrics.html
30. android.content.res.Configuration : http://developer.android.com/reference/android/content/res/Configuration.html
31. Espace de coordonnées du capteur : http://developer.android.com/reference/android/hardware/SensorEvent.html
32. API Bluetooth : http://developer.android.com/reference/android/bluetooth/package-summary.html
33. Protocole Push NDEF : http://source.android.com/compatibility/ndef-push-protocol.pdf
34. MIFARE MF1S503X : http://www.nxp.com/documents/data_sheet/MF1S503x.pdf
35. MIFARE MF1S703X : http://www.nxp.com/documents/data_sheet/MF1S703x.pdf
36. MIFARE MF0ICU1 : http://www.nxp.com/documents/data_sheet/MF0ICU1.pdf
37. MIFARE MF0ICU2 : http://www.nxp.com/documents/short_data_sheet/MF0ICU2_SDS.pdf
38. MIFARE AN130511 : http://www.nxp.com/documents/application_note/AN130511.pdf
39. MIFARE AN130411 : http://www.nxp.com/documents/application_note/AN130411.pdf
40. API d'orientation de la caméra : http://developer.android.com/reference/android/hardware/Camera.html#setDisplayOrientation(int)
41. android.hardware.Camera : http://developer.android.com/reference/android/hardware/Camera.html
42. Référence sur la sécurité et les autorisations d'Android : http://developer.android.com/guide/topics/security/security.html
43. Applications pour Android : http://code.google.com/p/apps-for-android

La plupart de ces ressources sont dérivées directement ou indirectement du SDK Android 2.3 et seront fonctionnellement identiques aux informations contenues dans la documentation de ce SDK. Dans tous les cas où cette définition de compatibilité ou la suite de tests de compatibilité sont en désaccord avec la documentation du SDK, la documentation du SDK est considérée comme faisant autorité. Tous les détails techniques fournis dans les références incluses ci-dessus sont considérés par inclusion comme faisant partie de cette définition de compatibilité.

3. Logiciel

La plate-forme Android comprend un ensemble d'API gérées, un ensemble d'API natives et un ensemble d'API dites "soft" telles que le système d'intention et les API d'applications Web. Cette section détaille les API matérielles et logicielles qui font partie intégrante de la compatibilité, ainsi que certains autres comportements techniques et d'interface utilisateur pertinents. Les implémentations de dispositifs DOIVENT être conformes à toutes les exigences de cette section.

3.1. Compatibilité des API gérées

L'environnement d'exécution géré (basé sur Dalvik) est le principal véhicule des applications Android. L'interface de programmation d'applications (API) Android est l'ensemble des interfaces de plate-forme Android exposées aux applications exécutées dans l'environnement de machine virtuelle gérée. Les implémentations d'appareils DOIVENT fournir des implémentations complètes, y compris tous les comportements documentés, de toute API documentée exposée par le SDK Android 2.3 [ Ressources, 4 ].

Les implémentations d'appareils NE DOIVENT PAS omettre d'API gérées, modifier les interfaces ou les signatures d'API, s'écarter du comportement documenté ou inclure des opérations sans opération, sauf lorsque cela est spécifiquement autorisé par cette définition de compatibilité.

Cette définition de compatibilité permet à certains types de matériel pour lesquels Android inclut des API d'être omis par les implémentations d'appareils. Dans de tels cas, les API DOIVENT toujours être présentes et se comporter de manière raisonnable. Voir la section 7 pour les exigences spécifiques à ce scénario.

3.2. Compatibilité de l'API logicielle

En plus des API gérées de la section 3.1, Android inclut également une importante API "soft" d'exécution uniquement, sous la forme d'éléments tels que les intentions, les autorisations et les aspects similaires des applications Android qui ne peuvent pas être appliqués au moment de la compilation de l'application. Cette section détaille les API "soft" et les comportements système requis pour la compatibilité avec Android 2.3. Les implémentations d'appareils DOIVENT répondre à toutes les exigences présentées dans cette section.

3.2.1. Autorisations

Les implémenteurs de périphériques DOIVENT prendre en charge et appliquer toutes les constantes d'autorisation comme documenté par la page de référence des autorisations [ Ressources, 5 ]. Notez que la section 10 répertorie les exigences supplémentaires liées au modèle de sécurité Android.

3.2.2. Paramètres de construction

Les API Android incluent un certain nombre de constantes sur la classe android.os.Build [ Ressources, 6 ] qui sont destinées à décrire l'appareil actuel. Pour fournir des valeurs cohérentes et significatives dans toutes les implémentations d'appareils, le tableau ci-dessous inclut des restrictions supplémentaires sur les formats de ces valeurs auxquelles les implémentations d'appareils DOIVENT se conformer.

3.2.3. Compatibilité d'intention

Android utilise Intents pour réaliser une intégration faiblement couplée entre les applications. Cette section décrit les exigences liées aux modèles d'intention qui DOIVENT être honorées par les implémentations de dispositifs. Par "honoré", cela signifie que l'implémenteur de l'appareil DOIT fournir une activité ou un service Android qui spécifie un filtre d'intention correspondant et se lie à et implémente le comportement correct pour chaque modèle d'intention spécifié.

3.2.3.1. Intentions d'application de base

Le projet Android en amont définit un certain nombre d'applications principales, telles qu'un numéroteur téléphonique, un calendrier, un carnet de contacts, un lecteur de musique, etc. Les implémenteurs de dispositifs PEUVENT remplacer ces applications par des versions alternatives.

Cependant, toutes ces versions alternatives DOIVENT respecter les mêmes modèles d'intention fournis par le projet en amont. Par exemple, si un appareil contient un lecteur de musique alternatif, il doit toujours respecter le modèle d'intention émis par les applications tierces pour choisir une chanson.

Les applications suivantes sont considérées comme des applications principales du système Android :

• Horloge de bureau
• Le navigateur
• Calendrier
• Calculatrice
• Contacts
• E-mail
• Galerie
• Recherche globale
• Lanceur
• Musique
• Paramètres

Les principales applications du système Android incluent divers composants d'activité ou de service considérés comme "publics". C'est-à-dire que l'attribut "android:exported" peut être absent ou avoir la valeur "true".

Pour chaque activité ou service défini dans l'une des applications principales du système Android qui n'est pas marqué comme non public via un attribut android:exported avec la valeur "false", les implémentations d'appareils DOIVENT inclure un composant du même type implémentant le même filtre d'intention patterns en tant qu'application principale du système Android.

En d'autres termes, une implémentation d'appareil PEUT remplacer les principales applications du système Android ; cependant, si c'est le cas, l'implémentation de l'appareil DOIT prendre en charge tous les modèles d'intention définis par chaque application système Android principale remplacée.

3.2.3.2. Remplacements d'intention

Comme Android est une plate-forme extensible, les implémenteurs d'appareils DOIVENT permettre à chaque modèle d'intention référencé à la section 3.2.3.1 d'être remplacé par des applications tierces. Le projet open source Android en amont le permet par défaut ; les implémenteurs d'appareils NE DOIVENT PAS attacher de privilèges spéciaux à l'utilisation par les applications système de ces modèles d'intention, ni empêcher les applications tierces de se lier à ces modèles et d'en prendre le contrôle. Cette interdiction inclut spécifiquement, mais sans s'y limiter, la désactivation de l'interface utilisateur "Chooser" qui permet à l'utilisateur de choisir entre plusieurs applications qui gèrent toutes le même modèle d'intention.

3.2.3.3. Espaces de noms d'intention

Les implémenteurs d'appareils NE DOIVENT PAS inclure de composant Android qui honore de nouveaux modèles d'intention ou d'intention de diffusion à l'aide d'une ACTION, d'une CATÉGORIE ou d'une autre chaîne de clé dans l'espace de noms android.*. Les implémenteurs d'appareils NE DOIVENT PAS inclure de composants Android qui honorent de nouveaux modèles d'intention ou d'intention de diffusion à l'aide d'une ACTION, d'une CATÉGORIE ou d'une autre chaîne de clé dans un espace de package appartenant à une autre organisation. Les implémenteurs d'appareils NE DOIVENT PAS modifier ou étendre les modèles d'intention utilisés par les applications principales répertoriées dans la section 3.2.3.1.

Cette interdiction est analogue à celle spécifiée pour les classes de langage Java dans la section 3.6.

3.2.3.4. Intentions de diffusion

Les applications tierces s'appuient sur la plateforme pour diffuser certaines intentions afin de les notifier des modifications de l'environnement matériel ou logiciel. Les appareils compatibles avec Android DOIVENT diffuser les intentions de diffusion publique en réponse aux événements système appropriés. Les intentions de diffusion sont décrites dans la documentation du SDK.

3.3. Compatibilité API native

Le code managé s'exécutant dans Dalvik peut appeler le code natif fourni dans le fichier .apk de l'application en tant que fichier ELF .so compilé pour l'architecture matérielle du périphérique approprié. Comme le code natif dépend fortement de la technologie de processeur sous-jacente, Android définit un certain nombre d'interfaces binaires d'application (ABI) dans le NDK Android, dans le fichier docs/CPU-ARCH-ABIS.txt . Si une implémentation de périphérique est compatible avec un ou plusieurs ABI définis, elle DEVRAIT implémenter la compatibilité avec le NDK Android, comme ci-dessous.

Si une implémentation d'appareil inclut la prise en charge d'un ABI Android, elle :

• DOIT inclure la prise en charge du code s'exécutant dans l'environnement géré pour appeler le code natif, à l'aide de la sémantique JNI (Java Native Interface) standard.
• DOIT être compatible avec la source (c'est-à-dire compatible avec l'en-tête) et compatible avec le binaire (pour l'ABI) avec chaque bibliothèque requise dans la liste ci-dessous
• DOIT signaler avec précision l'interface binaire d'application (ABI) native prise en charge par l'appareil, via l'API android.os.Build.CPU_ABI
• DOIT signaler uniquement les ABI documentés dans la dernière version du NDK Android, dans le fichier docs/CPU-ARCH-ABIS.txt
• DEVRAIT être construit en utilisant le code source et les fichiers d'en-tête disponibles dans le projet open-source Android en amont

Les API de code natif suivantes DOIVENT être disponibles pour les applications qui incluent du code natif :

• libc (bibliothèque C)
• libm (bibliothèque mathématique)
• Prise en charge minimale de C++
• Interface JNI
• liblog (journalisation Android)
• libz (compression Zlib)
• libdl (lien dynamique)
• libGLESv1_CM.so (OpenGL ES 1.0)
• libGLESv2.so (OpenGL ES 2.0)
• libEGL.so (gestion de surface OpenGL native)
• libjnigraphics.so
• libOpenSLES.so (prise en charge audio de la bibliothèque de sons ouverte)
• libandroid.so (prise en charge native de l'activité Android)
• Prise en charge d'OpenGL, comme décrit ci-dessous

Notez que les futures versions du NDK Android peuvent introduire la prise en charge d'ABI supplémentaires. Si une mise en œuvre d'appareil n'est pas compatible avec un ABI prédéfini existant, elle NE DOIT PAS signaler la prise en charge d'un quelconque ABI.

La compatibilité du code natif est difficile. Pour cette raison, il convient de répéter que les implémenteurs de périphériques sont TRÈS fortement encouragés à utiliser les implémentations en amont des bibliothèques répertoriées ci-dessus pour garantir la compatibilité.

3.4. Compatibilité Internet

De nombreux développeurs et applications s'appuient sur le comportement de la classe android.webkit.WebView [ Ressources, 8 ] pour leurs interfaces utilisateur, de sorte que l'implémentation WebView doit être compatible entre les implémentations Android. De même, un navigateur Web complet et moderne est au cœur de l'expérience utilisateur Android. Les implémentations d'appareils DOIVENT inclure une version d' android.webkit.WebView compatible avec le logiciel Android en amont, et DOIVENT inclure un navigateur moderne compatible HTML5, comme décrit ci-dessous.

3.4.1. Compatibilité WebView

L'implémentation Android Open Source utilise le moteur de rendu WebKit pour implémenter android.webkit.WebView . Comme il n'est pas possible de développer une suite de tests complète pour un système de rendu Web, les implémenteurs d'appareils DOIVENT utiliser la version amont spécifique de WebKit dans l'implémentation de WebView. Spécifiquement:

• Les implémentations android.webkit.WebView des implémentations d'appareils DOIVENT être basées sur la version WebKit 533.1 à partir de l'arborescence Open Source Android en amont pour Android 2.3. Cette version inclut un ensemble spécifique de fonctionnalités et de correctifs de sécurité pour WebView. Les implémenteurs d'appareils PEUVENT inclure des personnalisations dans l'implémentation de WebKit ; cependant, de telles personnalisations NE DOIVENT PAS modifier le comportement de WebView, y compris le comportement de rendu.
• La chaîne de l'agent utilisateur signalée par WebView DOIT être au format suivant :
  Mozilla/5.0 (Linux; U; Android $(VERSION); $(LOCALE); $(MODEL) Build/$(BUILD)) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1
  • La valeur de la chaîne $(VERSION) DOIT être la même que la valeur pour android.os.Build.VERSION.RELEASE
  • La valeur de la chaîne $(LOCALE) DEVRAIT suivre les conventions ISO pour le code de pays et la langue, et DEVRAIT se référer aux paramètres régionaux actuellement configurés de l'appareil
  • La valeur de la chaîne $(MODEL) DOIT être la même que la valeur pour android.os.Build.MODEL
  • La valeur de la chaîne $(BUILD) DOIT être identique à la valeur de android.os.Build.ID

Le composant WebView DEVRAIT inclure la prise en charge d'autant de HTML5 [ Ressources, 9 ] que possible. Au minimum, les implémentations d'appareils DOIVENT prendre en charge chacune de ces API associées à HTML5 dans WebView :

• cache d'application/opération hors ligne [ Ressources, 10 ]
• la balise <video> [ Ressources, 11 ]
• géolocalisation [ Ressources, 12 ]

De plus, les implémentations d'appareils DOIVENT prendre en charge l'API de stockage Web HTML5/W3C [ Ressources, 13 ], et DEVRAIENT prendre en charge l'API HTML5/W3C IndexedDB [ Ressources, 14 ]. Notez qu'à mesure que les organismes de normalisation du développement Web évoluent pour favoriser IndexedDB plutôt que le stockage Web, IndexedDB devrait devenir un composant requis dans une future version d'Android.

Les API HTML5, comme toutes les API JavaScript, DOIVENT être désactivées par défaut dans une WebView, à moins que le développeur ne les active explicitement via les API Android habituelles.

3.4.2. Compatibilité du navigateur

Les implémentations d'appareils DOIVENT inclure une application de navigateur autonome pour la navigation Web générale des utilisateurs. Le navigateur autonome PEUT être basé sur une technologie de navigateur autre que WebKit. Cependant, même si une autre application de navigateur est utilisée, le composant android.webkit.WebView fourni aux applications tierces DOIT être basé sur WebKit, comme décrit dans la section 3.4.1.

Les mises en œuvre PEUVENT expédier une chaîne d'agent utilisateur personnalisée dans l'application de navigateur autonome.

L'application de navigateur autonome (qu'elle soit basée sur l'application de navigateur WebKit en amont ou sur un remplacement tiers) DEVRAIT inclure la prise en charge d'autant de HTML5 [ Ressources, 9 ] que possible. Au minimum, les implémentations d'appareils DOIVENT prendre en charge chacune de ces API associées à HTML5 :

• cache d'application/opération hors ligne [ Ressources, 10 ]
• la balise <video> [ Ressources, 11 ]
• géolocalisation [ Ressources, 12 ]

De plus, les implémentations d'appareils DOIVENT prendre en charge l'API de stockage Web HTML5/W3C [ Ressources, 13 ], et DEVRAIENT prendre en charge l'API HTML5/W3C IndexedDB [ Ressources, 14 ]. Notez qu'à mesure que les organismes de normalisation du développement Web évoluent pour favoriser IndexedDB plutôt que le stockage Web, IndexedDB devrait devenir un composant requis dans une future version d'Android.

3.5. Compatibilité comportementale de l'API

Les comportements de chacun des types d'API (géré, logiciel, natif et Web) doivent être cohérents avec l'implémentation préférée du projet open source Android en amont [ Ressources, 3 ]. Certains domaines de compatibilité spécifiques sont :

• Les appareils NE DOIVENT PAS modifier le comportement ou la sémantique d'une intention standard
• Les appareils NE DOIVENT PAS modifier le cycle de vie ou la sémantique du cycle de vie d'un type particulier de composant système (tel que Service, Activity, ContentProvider, etc.)
• Les appareils NE DOIVENT PAS modifier la sémantique d'une autorisation standard

La liste ci-dessus n'est pas exhaustive. La suite de tests de compatibilité (CTS) teste des parties importantes de la plate-forme pour la compatibilité comportementale, mais pas toutes. Il est de la responsabilité de l'implémenteur d'assurer la compatibilité comportementale avec le projet Open Source Android. Pour cette raison, les implémenteurs d'appareils DEVRAIENT utiliser le code source disponible via le projet Android Open Source dans la mesure du possible, plutôt que de réimplémenter des parties importantes du système.

3.6. Espaces de noms d'API

Android suit les conventions d'espace de noms de package et de classe définies par le langage de programmation Java. Pour garantir la compatibilité avec les applications tierces, les implémenteurs d'appareils NE DOIVENT PAS apporter de modifications interdites (voir ci-dessous) à ces espaces de noms de packages :

• Java.*
• javax.*
• Soleil.*
• Android.*
• com.android.*

Les modifications interdites incluent :

• Les implémentations d'appareils NE DOIVENT PAS modifier les API exposées publiquement sur la plate-forme Android en modifiant les signatures de méthode ou de classe, ou en supprimant des classes ou des champs de classe.
• Les implémenteurs d'appareils PEUVENT modifier l'implémentation sous-jacente des API, mais ces modifications NE DOIVENT PAS avoir d'impact sur le comportement déclaré et la signature en langage Java des API exposées publiquement.
• Les implémenteurs d'appareils NE DOIVENT PAS ajouter d'éléments exposés publiquement (tels que des classes ou des interfaces, ou des champs ou des méthodes aux classes ou interfaces existantes) aux API ci-dessus.

Un "élément exposé publiquement" est toute construction qui n'est pas décorée avec le marqueur "@hide" tel qu'utilisé dans le code source Android en amont. En d'autres termes, les implémenteurs d'appareils NE DOIVENT PAS exposer de nouvelles API ni modifier les API existantes dans les espaces de noms indiqués ci-dessus. Les implémenteurs d'appareils PEUVENT apporter des modifications uniquement internes, mais ces modifications NE DOIVENT PAS être annoncées ou autrement exposées aux développeurs.

Les implémenteurs d'appareils PEUVENT ajouter des API personnalisées, mais ces API NE DOIVENT PAS se trouver dans un espace de noms appartenant à ou se référant à une autre organisation. Par exemple, les implémenteurs d'appareils NE DOIVENT PAS ajouter d'API à l'espace de noms com.google.* ou similaire ; seul Google peut le faire. De même, Google NE DOIT PAS ajouter d'API aux espaces de noms d'autres sociétés. De plus, si une implémentation de périphérique inclut des API personnalisées en dehors de l'espace de noms Android standard, ces API DOIVENT être regroupées dans une bibliothèque partagée Android afin que seules les applications qui les utilisent explicitement (via le mécanisme <uses-library> ) soient affectées par l'utilisation accrue de la mémoire. de telles API.

Si un implémenteur d'appareil propose d'améliorer l'un des espaces de noms de package ci-dessus (par exemple en ajoutant de nouvelles fonctionnalités utiles à une API existante ou en ajoutant une nouvelle API), l'implémenteur DEVRAIT visiter source.android.com et commencer le processus de contribution aux modifications et code, selon les informations sur ce site.

Notez que les restrictions ci-dessus correspondent aux conventions standard pour nommer les API dans le langage de programmation Java ; cette section vise simplement à renforcer ces conventions et à les rendre contraignantes en les incluant dans cette définition de compatibilité.

3.7. Compatibilité des machines virtuelles

Les implémentations de périphériques DOIVENT prendre en charge la spécification complète du bytecode Dalvik Executable (DEX) et la sémantique de la machine virtuelle Dalvik [ Ressources, 15 ].

Les implémentations d'appareils avec des écrans classés comme moyenne ou basse densité DOIVENT configurer Dalvik pour allouer au moins 16 Mo de mémoire à chaque application. Les implémentations d'appareils avec des écrans classés comme haute densité ou très haute densité DOIVENT configurer Dalvik pour allouer au moins 24 Mo de mémoire à chaque application. Notez que les implémentations de périphériques PEUVENT allouer plus de mémoire que ces chiffres.

3.8. Compatibilité de l'interface utilisateur

La plate-forme Android comprend certaines API de développeur qui permettent aux développeurs de se connecter à l'interface utilisateur du système. Les implémentations d'appareils DOIVENT incorporer ces API d'interface utilisateur standard dans les interfaces utilisateur personnalisées qu'elles développent, comme expliqué ci-dessous.

3.8.1. Widget

Android définit un type de composant et l'API et le cycle de vie correspondants qui permettent aux applications d'exposer un "AppWidget" à l'utilisateur final [ Ressources, 16 ]. La version de référence Android Open Source comprend une application Launcher qui comprend des éléments d'interface utilisateur permettant à l'utilisateur d'ajouter, d'afficher et de supprimer des AppWidgets de l'écran d'accueil.

Les implémenteurs d'appareils PEUVENT substituer une alternative au lanceur de référence (c'est-à-dire l'écran d'accueil). Les lanceurs alternatifs DEVRAIENT inclure une prise en charge intégrée des AppWidgets et exposer des éléments d'interface utilisateur pour ajouter, configurer, afficher et supprimer des AppWidgets directement dans le lanceur. Les lanceurs alternatifs PEUVENT omettre ces éléments d'interface utilisateur ; cependant, s'ils sont omis, l'implémenteur de l'appareil DOIT fournir une application distincte accessible depuis le lanceur qui permet aux utilisateurs d'ajouter, de configurer, d'afficher et de supprimer des AppWidgets.

3.8.2. Avis

Android inclut des API qui permettent aux développeurs d'informer les utilisateurs d'événements notables [ Ressources, 17 ]. Les implémenteurs de dispositifs DOIVENT assurer la prise en charge de chaque classe de notification ainsi définie ; plus précisément : sons, vibrations, lumière et barre d'état.

De plus, l'implémentation DOIT restituer correctement toutes les ressources (icônes, fichiers son, etc.) fournies dans les API [ Ressources, 18 ], ou dans le guide de style des icônes de la barre d'état [ Ressources, 19 ]. Les implémenteurs d'appareils PEUVENT fournir une expérience utilisateur alternative pour les notifications que celle fournie par l'implémentation Android Open Source de référence ; cependant, de tels systèmes de notification alternatifs DOIVENT prendre en charge les ressources de notification existantes, comme ci-dessus.

3.8.3. Rechercher

Android inclut des API [ Ressources, 20 ] qui permettent aux développeurs d'intégrer la recherche dans leurs applications et d'exposer les données de leurs applications dans la recherche globale du système. Generally speaking, this functionality consists of a single, system-wide user interface that allows users to enter queries, displays suggestions as users type, and displays results. The Android APIs allow developers to reuse this interface to provide search within their own apps, and allow developers to supply results to the common global search user interface.

Device implementations MUST include a single, shared, system-wide search user interface capable of real-time suggestions in response to user input. Device implementations MUST implement the APIs that allow developers to reuse this user interface to provide search within their own applications. Device implementations MUST implement the APIs that allow third-party applications to add suggestions to the search box when it is run in global search mode. If no third-party applications are installed that make use of this functionality, the default behavior SHOULD be to display web search engine results and suggestions.

Device implementations MAY ship alternate search user interfaces, but SHOULD include a hard or soft dedicated search button, that can be used at any time within any app to invoke the search framework, with the behavior provided for in the API documentation.

3.8.4. Toasts

Applications can use the "Toast" API (defined in [ Resources, 21 ]) to display short non-modal strings to the end user, that disappear after a brief period of time. Device implementations MUST display Toasts from applications to end users in some high-visibility manner.

3.8.5. Live Wallpapers

Android defines a component type and corresponding API and lifecycle that allows applications to expose one or more "Live Wallpapers" to the end user [ Resources, 22 ]. Live Wallpapers are animations, patterns, or similar images with limited input capabilities that display as a wallpaper, behind other applications.

Hardware is considered capable of reliably running live wallpapers if it can run all live wallpapers, with no limitations on functionality, at a reasonable framerate with no adverse affects on other applications. If limitations in the hardware cause wallpapers and/or applications to crash, malfunction, consume excessive CPU or battery power, or run at unacceptably low frame rates, the hardware is considered incapable of running live wallpaper. As an example, some live wallpapers may use an Open GL 1.0 or 2.0 context to render their content. Live wallpaper will not run reliably on hardware that does not support multiple OpenGL contexts because the live wallpaper use of an OpenGL context may conflict with other applications that also use an OpenGL context.

Device implementations capable of running live wallpapers reliably as described above SHOULD implement live wallpapers. Device implementations determined to not run live wallpapers reliably as described above MUST NOT implement live wallpapers.

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 [ Resources, 23 ].

Devices implementations MUST NOT extend either the .apk [ Resources, 24 ], Android Manifest [ Resources, 25 ], or Dalvik bytecode [ Resources, 15 ] formats in such a way that would prevent those files from installing and running correctly on other compatible devices. Device implementers SHOULD use the reference upstream implementation of Dalvik, and the reference implementation's package management system.

5. Multimedia Compatibility

Device implementations MUST fully implement all multimedia APIs. Device implementations MUST include support for all multimedia codecs described below, and SHOULD meet the sound processing guidelines described below. Device implementations MUST include at least one form of audio output, such as speakers, headphone jack, external speaker connection, etc.

5.1. Media Codecs

Device implementations MUST support the multimedia codecs as detailed in the following sections. All of these codecs 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 unencumbered by 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.

The tables below do not list specific bitrate requirements for most video codecs. The reason for this is that in practice, current device hardware does not necessarily support bitrates that map exactly to the required bitrates specified by the relevant standards. Instead, device implementations SHOULD support the highest bitrate practical on the hardware, up to the limits defined by the specifications.

5.1.1. Media Decoders

Device implementations MUST include an implementation of a decoder for each codec and format described in the table below. Note that decoders for each of these media types are provided by the upstream Android Open-Source Project.

5.1.2. Media Encoders

Device implementations SHOULD include encoders for as many of the media formats listed in Section 5.1.1. as possible. However, some encoders do not make sense for devices that lack certain optional hardware; for instance, an encoder for the H.263 video does not make sense, if the device lacks any cameras. Device implementations MUST therefore implement media encoders according to the conditions described in the table below.

See Section 7 for details on the conditions under which hardware may be omitted by device implementations.

In addition to the encoders listed above, device implementations SHOULD include an H.264 encoder. Note that the Compatibility Definition for a future version is planned to change this requirement to "MUST". That is, H.264 encoding is optional in Android 2.3 but will be required by a future version. Existing and new devices that run Android 2.3 are very strongly encouraged to meet this requirement in Android 2.3 , or they will not be able to attain Android compatibility when upgraded to the future version.

5.2. Audio Recording

When an application has used the android.media.AudioRecord API to start recording an audio stream, device implementations SHOULD sample and record audio with each of these behaviors:

• Noise reduction processing, if present, SHOULD be disabled.
• Automatic gain control, if present, SHOULD be disabled.
• 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 5000 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% from 100 Hz to 4000 Hz at 90 dB SPL input level.

Note: while the requirements outlined above are stated as "SHOULD" for Android 2.3, the Compatibility Definition for a future version is planned to change these to "MUST". That is, these requirements are optional in Android 2.3 but will be required by a future version. Existing and new devices that run Android 2.3 are very strongly encouraged to meet these requirements in Android 2.3 , or they will not be able to attain Android compatibility when upgraded to the future version.

5.3. Audio Latency

Audio latency is broadly defined as the interval between when an application requests an audio playback or record operation, and when the device implementation actually begins the operation. Many classes of applications rely on short latencies, to achieve real-time effects such sound effects or VOIP communication. Device implementations that include microphone hardware and declare android.hardware.microphone SHOULD meet all audio latency requirements outlined in this section. See Section 7 for details on the conditions under which microphone hardware may be omitted by device implementations.

For the purposes of this section:

• "cold output latency" is defined to be the interval between when an application requests audio playback and when sound begins playing, when the audio system has been idle and powered down prior to the request
• "warm output latency" is defined to be the interval between when an application requests audio playback and when sound begins playing, when the audio system has been recently used but is currently idle (that is, silent)
• "continuous output latency" is defined to be the interval between when an application issues a sample to be played and when the speaker physically plays the corresponding sound, while the device is currently playing back audio
• "cold input latency" is defined to be the interval between when an application requests audio recording and when the first sample is delivered to the application via its callback, when the audio system and microphone has been idle and powered down prior to the request
• "continuous input latency" is defined to be when an ambient sound occurs and when the sample corresponding to that sound is delivered to a recording application via its callback, while the device is in recording mode

Using the above definitions, device implementations SHOULD exhibit each of these properties:

• cold output latency of 100 milliseconds or less
• warm output latency of 10 milliseconds or less
• continuous output latency of 45 milliseconds or less
• cold input latency of 100 milliseconds or less
• continuous input latency of 50 milliseconds or less

Note: while the requirements outlined above are stated as "SHOULD" for Android 2.3, the Compatibility Definition for a future version is planned to change these to "MUST". That is, these requirements are optional in Android 2.3 but will be required by a future version. Existing and new devices that run Android 2.3 are very strongly encouraged to meet these requirements in Android 2.3 , or they will not be able to attain Android compatibility when upgraded to the future version.

If a device implementation meets the requirements of this section, it MAY report support for low-latency audio, by reporting the feature "android.hardware.audio.low-latency" via the android.content.pm.PackageManager class. [ Resources, 27 ] Conversely, if the device implementation does not meet these requirements it MUST NOT report support for low-latency audio.

6. Developer Tool Compatibility

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

• Android Debug Bridge (known as adb) [ Resources, 23 ]
  Device implementations MUST support all adb functions as documented in the Android SDK. The device-side adb daemon SHOULD be inactive by default, but there MUST be a user-accessible mechanism to turn on the Android Debug Bridge.
• Dalvik Debug Monitor Service (known as ddms) [ Resources, 23 ]
  Device implementations MUST support all ddms features as documented in the Android SDK. As ddms uses adb , support for ddms SHOULD be inactive by default, but MUST be supported whenever the user has activated the Android Debug Bridge, as above.
• Monkey [ Resources, 26 ]
  Device implementations MUST include the Monkey framework, and make it available for applications to use.

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, and Windows 7, in both 32-bit and 64-bit versions.

7. Hardware Compatibility

Android is intended to enable device implementers to create innovative form factors and configurations. At the same time Android developers write innovative applications that rely on the various hardware and features available through the Android APIs. The requirements in this section strike a balance between innovations available to device implementers, and the needs of developers to ensure their apps are only available to devices where they will run properly.

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's APIs MUST still be present
• 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 accurately report accurate hardware configuration information via the getSystemAvailableFeatures() and hasSystemFeature(String) methods on the android.content.pm.PackageManager class. [ Resources, 27 ]

7.1. Display and Graphics

Android 2.3 includes facilities that automatically adjust application assets and UI layouts appropriately for the device, to ensure that third-party applications run well on a variety of hardware configurations [ Resources, 28 ]. Devices MUST properly implement these APIs and behaviors, as detailed in this section.

7.1.1. Screen Configurations

Device implementations MAY use screens of any pixel dimensions, provided that they meet the following requirements:

• screens MUST be at least 2.5 inches in physical diagonal size
• density MUST be at least 100 dpi
• the aspect ratio MUST be between 1.333 (4:3) and 1.779 (16:9)
• the display technology used consists of square pixels

Device implementations with a screen meeting the requirements above are considered compatible, and no additional action is necessary. The Android framework implementation automatically computes display characteristics such as screen size bucket and density bucket. In the majority of cases, the framework decisions are the correct ones. If the default framework computations are used, no additional action is necessary. Device implementers wishing to change the defaults, or use a screen that does not meet the requirements above MUST contact the Android Compatibility Team for guidance, as provided for in Section 12.

The units used by the requirements above are defined as follows:

• "Physical diagonal size" is the distance in inches between two opposing corners of the illuminated portion of the display.
• "dpi" (meaning "dots per inch") is the number of pixels encompassed by a linear horizontal or vertical span of 1". Where dpi values are listed, both horizontal and vertical dpi must fall within the range.
• "Aspect ratio" is the ratio of the longer dimension of the screen to the shorter dimension. For example, a display of 480x854 pixels would be 854 / 480 = 1.779, or roughly "16:9".

Device implementations MUST use only displays with a single static configuration. That is, device implementations MUST NOT enable multiple screen configurations. For instance, since a typical television supports multiple resolutions such as 1080p, 720p, and so on, this configuration is not compatible with Android 2.3. (However, support for such configurations is under investigation and planned for a future version of Android.)

7.1.2. Display Metrics

Device implementations MUST report correct values for all display metrics defined in android.util.DisplayMetrics [ Resources, 29 ].

7.1.3. Declared Screen Support

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, medium, and large screens, as described in the Android SDK documentation.

7.1.4. Screen Orientation

Compatible devices 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 that cannot be physically rotated MAY meet this requirement by "letterboxing" applications that request portrait mode, using only a portion of the available display.

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.

7.1.5. 3D Graphics Acceleration

Device implementations MUST support OpenGL ES 1.0, as required by the Android 2.3 APIs. For devices that lack 3D acceleration hardware, a software implementation of OpenGL ES 1.0 is provided by the upstream Android Open-Source Project. Device implementations SHOULD support OpenGL ES 2.0.

Implementations MAY omit Open GL ES 2.0 support; however if support is omitted, device implementations MUST NOT report as supporting OpenGL ES 2.0. Specifically, if a device implementations lacks OpenGL ES 2.0 support:

• the managed APIs (such as via the GLES10.getString() method) MUST NOT report support for OpenGL ES 2.0
• the native C/C++ OpenGL APIs (that is, those available to apps via libGLES_v1CM.so, libGLES_v2.so, or libEGL.so) MUST NOT report support for OpenGL ES 2.0.

Conversely, if a device implementation does support OpenGL ES 2.0, it MUST accurately report that support via the routes just listed.

Note that Android 2.3 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 2.3 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.

7.2. Input Devices

Android 2.3 supports a number of modalities for user input. Device implementations MUST support user input devices as provided for in this section.

7.2.1. Keyboard

Device implementations:

• MUST include support for the Input Management Framework (which allows third party developers to create Input Management Engines -- ie soft keyboard) as detailed at developer.android.com
• MUST provide at least one soft keyboard implementation (regardless of whether a hard keyboard is present)
• MAY include additional soft keyboard implementations
• MAY include a hardware keyboard
• MUST NOT include a hardware keyboard that does not match one of the formats specified in android.content.res.Configuration.keyboard [ Resources, 30 ] (that is, QWERTY, or 12-key)

7.2.2. Non-touch Navigation

Device implementations:

• MAY omit a non-touch navigation option (that is, may omit a trackball, d-pad, or wheel)
• MUST report the correct value for android.content.res.Configuration.navigation [ Resources, 30 ]
• 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 code includes a selection mechanism suitable for use with devices that lack non-touch navigation inputs.

7.2.3. Navigation keys

The Home, Menu and Back functions are essential to the Android navigation paradigm. Device implementations MUST make these functions available to the user at all times, regardless of application state. These functions SHOULD be implemented via dedicated buttons. They MAY be implemented using software, gestures, touch panel, etc., but if so they MUST be always accessible and not obscure or interfere with the available application display area.

Device implementers SHOULD also provide a dedicated search key. Device implementers MAY also provide send and end keys for phone calls.

7.2.4. Touchscreen input

Device implementations:

• MUST have a touchscreen
• MAY have either capacitive or resistive touchscreen
• MUST report the value of android.content.res.Configuration [ Resources, 30 ] reflecting corresponding to the type of the specific touchscreen on the device
• SHOULD support fully independently tracked pointers, if the touchscreen supports multiple pointers

7.3. Sensors

Android 2.3 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. For example, device implementations:

• MUST accurately report the presence or absence of sensors per the android.content.pm.PackageManager class. [ Resources, 27 ]
• 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.)

The list above is not comprehensive; the documented behavior of the Android SDK is to be considered authoritative.

Some sensor types are synthetic, 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.

The Android 2.3 APIs introduce a notion of a "streaming" sensor, which is one that returns data continuously, rather than only when the data changes. Device implementations MUST continuously provide periodic data samples for any API indicated by the Android 2.3 SDK documentation to be a streaming sensor.

7.3.1. Accelerometer

Device implementations SHOULD include a 3-axis accelerometer. If a device implementation does include a 3-axis accelerometer, it:

• MUST be able to deliver events at 50 Hz or greater
• MUST comply with the Android sensor coordinate system as detailed in the Android APIs (see [ Resources, 31 ])
• MUST be capable of measuring from freefall up to twice gravity (2g) or more on any three-dimensional vector
• MUST have 8-bits of accuracy or more
• MUST have a standard deviation no greater than 0.05 m/s^2

7.3.2. Magnetometer

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

• MUST be able to deliver events at 10 Hz or greater
• MUST comply with the Android sensor coordinate system as detailed in the Android APIs (see [ Resources, 31 ]).
• MUST be capable of sampling a range of field strengths adequate to cover the geomagnetic field
• MUST have 8-bits of accuracy or more
• MUST have a standard deviation no greater than 0.5 µT

7.3.3. GPS

Device implementations SHOULD include a GPS receiver. If a device implementation does include a GPS receiver, it SHOULD include some form of "assisted GPS" technique to minimize GPS lock-on time.

7.3.4. Gyroscope

Device implementations SHOULD include a gyroscope (ie 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 be capable of measuring orientation changes up to 5.5*Pi radians/second (that is, approximately 1,000 degrees per second)
• MUST be able to deliver events at 100 Hz or greater
• MUST have 8-bits of accuracy or more

7.3.5. Barometer

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

• MUST be able to deliver events at 5 Hz or greater
• MUST have adequate precision to enable estimating altitude

7.3.7. Thermometer

Device implementations MAY but SHOULD NOT include a thermometer (ie temperature sensor.) If a device implementation does include a thermometer, it MUST measure the temperature of the device CPU. It MUST NOT measure any other temperature. (Note that this sensor type is deprecated in the Android 2.3 APIs.)

7.3.7. Photometer

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

7.3.8. Proximity Sensor

Device implementations MAY 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. If a device implementation has a proximity sensor, it MUST be have 1-bit of accuracy or more.

7.4. Data Connectivity

Network connectivity and access to the Internet are vital features of Android. Meanwhile, device-to-device interaction adds significant value to Android devices and applications. Device implementations MUST meet the data connectivity requirements in this section.

7.4.1. Telephony

"Telephony" as used by the Android 2.3 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 2.3 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 sub-features, regardless of whether they use a cellular network for data connectivity.

Android 2.3 MAY be used on devices that do not include telephony hardware. That is, Android 2.3 is compatible with devices that are not phones. However, if a device implementation does include GSM or CDMA telephony, it MUST implement full support for the API for that technology. Device implementations that do not include telephony hardware MUST implement the full APIs as no-ops.

7.4.2. IEEE 802.11 (WiFi)

Android 2.3 device implementations SHOULD include support for one or more forms of 802.11 (b/g/a/n, etc.) If a device implementation does include support for 802.11, it MUST implement the corresponding Android API.

7.4.3. Bluetooth

Device implementations SHOULD include a Bluetooth transceiver. Device implementations that do include a Bluetooth transceiver MUST enable the RFCOMM-based Bluetooth API as described in the SDK documentation [ Resources, 32 ]. Device implementations SHOULD implement relevant Bluetooth profiles, such as A2DP, AVRCP, OBEX, etc. as appropriate for the device.

The Compatibility Test Suite includes cases that cover basic operation of the Android RFCOMM Bluetooth API. However, since Bluetooth is a communications protocol between devices, it cannot be fully tested by unit tests running on a single device. Consequently, device implementations MUST also pass the human-driven Bluetooth test procedure described in Appendix A.

7.4.4. Near-Field Communications

Device implementations SHOULD include a transceiver and related hardware for Near-Field Communications (NFC). If a device implementation does include NFC hardware, then it:

• MUST report the android.hardware.nfc feature from the android.content.pm.PackageManager.hasSystemFeature() method. [ Resources, 27 ]
• MUST be capable of reading and writing NDEF messages via the following NFC standards:
  • MUST be capable of acting as an NFC Forum reader/writer (as defined by the NFC Forum technical specification NFCForum-TS-DigitalProtocol-1.0) via the following NFC standards:
    • NfcA (ISO14443-3A)
    • NfcB (ISO14443-3B)
    • NfcF (JIS 6319-4)
    • NfcV (ISO 15693)
    • IsoDep (ISO 14443-4)
    • NFC Forum Tag Types 1, 2, 3, 4 (defined by the NFC Forum)
  • MUST be capable of transmitting and receiving data via the following peer-to-peer standards and protocols:
    • ISO 18092
    • LLCP 1.0 (defined by the NFC Forum)
    • SDP 1.0 (defined by the NFC Forum)
    • NDEF Push Protocol [ Resources, 33 ]
  • MUST scan for all supported technologies while in NFC discovery mode.
  • SHOULD be in NFC discovery mode while the device is awake with the screen active.

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

  Additionally, device implementations SHOULD support the following widely-deployed MIFARE technologies.

  • MIFARE Classic (NXP MF1S503x [ Resources, 34 ], MF1S703x [ Resources, 35 ])
  • MIFARE Ultralight (NXP MF0ICU1 [ Resources, 36 ], MF0ICU2 [ Resources, 37 ])
  • NDEF on MIFARE Classic (NXP AN130511 [ Resources, 38 ], AN130411 [ Resources, 39 ])

  Note that Android 2.3.3 includes APIs for these MIFARE types. If a device implementation supports MIFARE, 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. [ Resources, 27 ] Note that this is not a standard Android feature, and as such does not appear as a constant on the PackageManager class.
  • MUST NOT implement the corresponding Android APIs nor report the com.nxp.mifare feature unless it also implements general NFC support as described in this section

  If a device implementation does not include NFC hardware, it MUST NOT declare the android.hardware.nfc feature from the android.content.pm.PackageManager.hasSystemFeature() method [ Resources, 27 ], and MUST implement the Android 2.3 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, 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 (WiFi).

  Devices MAY implement more than one form of data connectivity.

  7.5. Cameras

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

  7.5.1. Rear-Facing Camera

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

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

  7.5.2. Front-Facing Camera

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

  • MUST have a resolution of at least VGA (that is, 640x480 pixels)
  • MUST NOT use a front-facing camera as the default for the Camera API. That is, the camera API in Android 2.3 has specific support for front-facing cameras, and device implementations MUST NOT configure the API to to treat a front-facing camera as the default rear-facing camera, even if it is the only camera on the device.
  • MAY include features (such as auto-focus, flash, etc.) available to rear-facing cameras as described in Section 7.5.1.
  • MUST horizontally reflect (ie mirror) the stream displayed by an app in a CameraPreview, as follows:
  • If the device implementation is capable of being rotated by user (such as automatically via an accelerometer or manually via user input), the camera preview MUST be mirrored horizontally relative to the device's current orientation.
  • If the current application has explicitly requested that the Camera display be rotated via a call to the android.hardware.Camera.setDisplayOrientation() [ Resources, 40 ] 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 data returned to any "postview" camera callback handlers, in the same manner as the camera preview image stream. (If the device implementation does not support postview callbacks, 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. Camera API Behavior

  Device implementations MUST implement the following behaviors for the camera-related APIs, for both front- and rear-facing cameras:

  1. 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.
  2. 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.
  3. Device implementations SHOULD support the YV12 format (as denoted by the android.graphics.ImageFormat.YV12 constant) for camera previews for both front- and rear-facing cameras. Note that the Compatibility Definition for a future version is planned to change this requirement to "MUST". That is, YV12 support is optional in Android 2.3 but will be required by a future version. Existing and new devices that run Android 2.3 are very strongly encouraged to meet this requirement in Android 2.3 , or they will not be able to attain Android compatibility when upgraded to the future version.

  Device implementations MUST implement the full Camera API included in the Android 2.3 SDK documentation [ Resources, 41 ]), 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.

  7.5.4. 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, a 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

  The fundamental function of Android 2.3 is to run applications. Device implementations MUST the requirements of this section, to ensure adequate storage and memory for applications to run properly.

  7.6.1. Minimum Memory and Storage

  Device implementations MUST have at least 128MB of memory available to the kernel and userspace. The 128MB MUST be in addition to any memory dedicated to hardware components such as radio, memory, and so on that is not under the kernel's control.

  Device implementations MUST have at least 150MB of non-volatile storage available for user data. That is, the /data partition MUST be at least 150MB.

  Beyond the requirements above, device implementations SHOULD have at least 1GB of non-volatile storage available for user data. Note that this higher requirement is planned to become a hard minimum in a future version of Android. Device implementations are strongly encouraged to meet these requirements now, or else they may not be eligible for compatibility for a future version of Android.

  The Android APIs include a Download Manager that applications may use to download data files. The Download Manager implementation MUST be capable of downloading individual files 55MB in size, or larger. The Download Manager implementation SHOULD be capable of downloading files 100MB in size, or larger.

  7.6.2. Application Shared Storage

  Device implementations MUST offer shared storage for applications. The shared storage provided MUST be at least 1GB in size.

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

  Device implementations 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 MAY have hardware for user-accessible removable storage, such as a Secure Digital card. Alternatively, device implementations MAY allocate internal (non-removable) storage as shared storage for apps.

  Regardless of the form of shared storage used, device implementations MUST provide some mechanism to access the contents of shared storage from a host computer, such as USB mass storage or Media Transfer Protocol.

  It is illustrative to consider two common examples. If a device implementation includes an SD card slot to satisfy the shared storage requirement, a FAT-formatted SD card 1GB in size or larger MUST be included with the device as sold to users, and MUST be mounted by default. Alternatively, if a device implementation uses internal fixed storage to satisfy this requirement, that storage MUST be 1GB in size or larger and mounted on /sdcard (or /sdcard MUST be a symbolic link to the physical location if it is mounted elsewhere.)

  Device implementations that include multiple shared storage paths (such as both an SD card slot and shared internal storage) SHOULD modify the core applications such as the media scanner and ContentProvider to transparently support files placed in both locations.

  7.7. USB

  Device implementations:

  • MUST implement a USB client, connectable to a USB host with a standard USB-A port
  • MUST implement the Android Debug Bridge over USB (as described in Section 7)
  • MUST implement the USB mass storage specification, to allow a host connected to the device to access the contents of the /sdcard volume
  • SHOULD use the micro USB form factor on the device side
  • MAY include a non-standard port on the device side, but if so MUST ship with a cable capable of connecting the custom pinout to standard USB-A port

  8. Performance Compatibility

  Compatible implementations must ensure not only that applications simply run correctly on the device, but that they do so with reasonable performance and overall good user experience. Device implementations MUST meet the key performance metrics of an Android 2.3 compatible device defined in the table below:

  Metric	Performance Threshold	Comments
  Application Launch Time	The following applications should launch within the specified time. Browser: less than 1300ms MMS/SMS: less than 700ms AlarmClock: less than 650ms	The launch time is measured as the total time to complete loading the default activity for the application, including the time it takes to start the Linux process, load the Android package into the Dalvik VM, and call onCreate.
  Simultaneous Applications	When multiple applications have been launched, re-launching an already-running application after it has been launched must take less than the original launch time.

  9. Security Model Compatibility

  Device implementations MUST implement a security model consistent with the Android platform security model as defined in Security and Permissions reference document in the APIs [ Resources, 42 ] 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 sub-sections.

  9.1. Permissions

  Device implementations MUST support the Android permissions model as defined in the Android developer documentation [ Resources, 42 ]. Specifically, implementations MUST enforce each permission defined as described in the SDK documentation; no permissions may be omitted, altered, or ignored. Implementations MAY add additional permissions, provided the new permission ID strings are not in the android.* namespace.

  9.2. UID and Process Isolation

  Device implementations MUST support the Android application sandbox model, in which each application runs as a unique Unix-style UID and in a separate process. Device implementations MUST support running multiple applications as the same Linux user ID, provided that the applications are properly signed and constructed, as defined in the Security and Permissions reference [ Resources, 42 ].

  9.3. Filesystem Permissions

  Device implementations MUST support the Android file access permissions model as defined in as defined in the Security and Permissions reference [ Resources, 42 ].

  9.4. Alternate Execution Environments

  Device implementations MAY include runtime environments that execute applications using some other software or technology than the Dalvik virtual machine 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 (that is, Linux user IDs, etc.)
  • Alternate runtimes MAY provide a single Android sandbox shared by all applications using the alternate runtime.
  • Alternate runtimes and installed applications using an alternate runtime MUST NOT reuse the sandbox of any other app installed on the device, except through the standard Android mechanisms of shared user ID and signing certificate
  • Alternate runtimes MUST NOT launch with, grant, or be granted access to the sandboxes corresponding to other Android applications.

  Alternate runtimes 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. That is, 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.

  10. Software Compatibility Testing

  The Android Open-Source Project includes various testing tools to verify that device implementations are compatible. Device implementations MUST pass all tests described in this section.

  However, note that no software test package is fully comprehensive. For this reason, device implementers are very strongly encouraged to make the minimum number of changes as possible to the reference and preferred implementation of Android 2.3 available from the Android Open-Source Project. This will minimize the risk of introducing bugs that create incompatibilities requiring rework and potential device updates.

  10.1. Compatibility Test Suite

  Device implementations MUST pass the Android Compatibility Test Suite (CTS) [ Resources, 2 ] 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 2.3. Device implementations MUST pass the latest CTS version available at the time the device software is completed.

  MUST pass the most recent version of the Android Compatibility Test Suite (CTS) available at the time of the device implementation's software is completed. (The CTS is available as part of the Android Open Source Project [ Resources, 2 ].) The CTS tests many, but not all, of the components outlined in this document.

  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 which 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 Verfier only by the set of included locales, branding, etc. MAY omit the CTS Verifier test.

  10.3. Reference Applications

  Device implementers MUST test implementation compatibility using the following open-source applications:

  • The "Apps for Android" applications [ Resources, 43 ].
  • Replica Island (available in Android Market; only required for device implementations that support with OpenGL ES 2.0)

  Each app above MUST launch and behave correctly on the implementation, for the implementation to be considered compatible.

  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

  The update mechanism used MUST support updates without wiping user data. Note that the upstream Android software includes an update mechanism that satisfies this requirement.

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

  12. Contact Us

  You can contact the document authors at compatibility@android.com for clarifications and to bring up any issues that you think the document does not cover.

  Appendix A - Bluetooth Test Procedure

  The Compatibility Test Suite includes cases that cover basic operation of the Android RFCOMM Bluetooth API. However, since Bluetooth is a communications protocol between devices, it cannot be fully tested by unit tests running on a single device. Consequently, device implementations MUST also pass the human-operated Bluetooth test procedure described below.

  The test procedure is based on the BluetoothChat sample app included in the Android open-source project tree. The procedure requires two devices:

  • a candidate device implementation running the software build to be tested
  • a separate device implementation already known to be compatible, and of a model from the device implementation being tested -- that is, a "known good" device implementation

  The test procedure below refers to these devices as the "candidate" and "known good" devices, respectively.

  Setup and Installation

  1. Build BluetoothChat.apk via 'make samples' from an Android source code tree.
  2. Install BluetoothChat.apk on the known-good device.
  3. Install BluetoothChat.apk on the candidate device.

  Test Bluetooth Control by Apps

  1. Launch BluetoothChat on the candidate device, while Bluetooth is disabled.
  2. Verify that the candidate device either turns on Bluetooth, or prompts the user with a dialog to turn on Bluetooth.

  Test Pairing and Communication

  1. Launch the Bluetooth Chat app on both devices.
  2. Make the known-good device discoverable from within BluetoothChat (using the Menu).
  3. On the candidate device, scan for Bluetooth devices from within BluetoothChat (using the Menu) and pair with the known-good device.
  4. Send 10 or more messages from each device, and verify that the other device receives them correctly.
  5. Close the BluetoothChat app on both devices by pressing Home .
  6. Unpair each device from the other, using the device Settings app.

  Test Pairing and Communication in the Reverse Direction

  1. Launch the Bluetooth Chat app on both devices.
  2. Make the candidate device discoverable from within BluetoothChat (using the Menu).
  3. On the known-good device, scan for Bluetooth devices from within BluetoothChat (using the Menu) and pair with the candidate device.
  4. Send 10 or messages from each device, and verify that the other device receives them correctly.
  5. Close the Bluetooth Chat app on both devices by pressing Back repeatedly to get to the Launcher.

  Test Re-Launches

  1. Re-launch the Bluetooth Chat app on both devices.
  2. Send 10 or messages from each device, and verify that the other device receives them correctly.

  Note: the above tests have some cases which end a test section by using Home, and some using Back. These tests are not redundant and are not optional: the objective is to verify that the Bluetooth API and stack works correctly both when Activities are explicitly terminated (via the user pressing Back, which calls finish()), and implicitly sent to background (via the user pressing Home.) Each test sequence MUST be performed as described.