Definição de compatibilidade do Android 2.3

Copyright © 2010, Google Inc. Todos os direitos reservados.
compatibilidade@android.com

Índice

1. Introdução

Este documento enumera os requisitos que devem ser atendidos para que os telefones celulares sejam compatíveis com o Android 2.3.

O uso de "must", "must not", "required", "shall", "shall not", "should", "should not", "recommended", "may" e "optional" é de acordo com o padrão IETF definido em RFC2119 [ Recursos, 1 ].

Conforme usado neste documento, um "implementador de dispositivo" ou "implementador" é uma pessoa ou organização que desenvolve uma solução de hardware/software executando o Android 2.3. Uma "implementação de dispositivo" ou "implementação" é a solução de hardware/software assim desenvolvida.

Para serem consideradas compatíveis com Android 2.3, as implementações de dispositivos DEVEM atender aos requisitos apresentados nesta Definição de Compatibilidade, incluindo quaisquer documentos incorporados por referência.

Quando esta definição ou os testes de software descritos na Seção 10 forem silenciosos, ambíguos ou incompletos, é responsabilidade do implementador do dispositivo garantir a compatibilidade com as implementações existentes. Por esta razão, o Android Open Source Project [ Resources, 3 ] é tanto a referência quanto a implementação preferida do Android. Os implementadores de dispositivos são fortemente incentivados a basear suas implementações, tanto quanto possível, no código-fonte "upstream" disponível no Android Open Source Project. Embora alguns componentes possam hipoteticamente ser substituídos por implementações alternativas, esta prática é fortemente desencorajada, pois passar nos testes de software se tornará substancialmente mais difícil. É responsabilidade do implementador garantir total compatibilidade comportamental com a implementação padrão do Android, incluindo e além do Conjunto de testes de compatibilidade. Finalmente, observe que certas substituições e modificações de componentes são explicitamente proibidas por este documento.

Observe que esta definição de compatibilidade foi emitida para corresponder à atualização 2.3.3 para Android, que é API de nível 10. Esta definição torna-se obsoleta e substitui a definição de compatibilidade para versões do Android 2.3 anteriores à 2.3.3. (Ou seja, as versões 2.3.1 e 2.3.2 estão obsoletas.) Os futuros dispositivos compatíveis com Android que executam o Android 2.3 DEVEM ser fornecidos com a versão 2.3.3 ou posterior.

2. Recursos

1. Níveis de requisitos IETF RFC2119: http://www.ietf.org/rfc/rfc2119.txt
2. Visão geral do programa de compatibilidade Android: http://source.android.com/docs/compatibility/index.html
3. Projeto de código aberto Android: http://source.android.com/
4. Definições e documentação da API: http://developer.android.com/reference/packages.html
5. Referência de permissões do Android: http://developer.android.com/reference/android/Manifest.permission.html
6. Referência android.os.Build: http://developer.android.com/reference/android/os/Build.html
7. Strings de versão permitidas no Android 2.3: http://source.android.com/docs/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. Recursos off-line do HTML5: http://dev.w3.org/html5/spec/Overview.html#offline
11. Tag de vídeo HTML5: http://dev.w3.org/html5/spec/Overview.html#video
12. API de geolocalização HTML5/W3C: http://www.w3.org/TR/geolocation-API/
13. API de banco de dados da web HTML5/W3C: http://www.w3.org/TR/webdatabase/
14. API HTML5/W3C IndexedDB: http://www.w3.org/TR/IndexedDB/
15. Especificação da Máquina Virtual Dalvik: disponível no código-fonte do Android, em dalvik/docs
16. AppWidgets: http://developer.android.com/guide/practices/ui_guidelines/widget_design.html
17. Notificações: http://developer.android.com/guide/topics/ui/notifiers/notifications.html
18. Recursos do aplicativo: http://code.google.com/android/reference/available-resources.html
19. Guia de estilo do ícone da barra de status: http://developer.android.com/guide/practices/ui_guideline /icon_design.html#statusbarstructure
20. Gerenciador de pesquisa: http://developer.android.com/reference/android/app/SearchManager.html
21. Brindes: http://developer.android.com/reference/android/widget/Toast.html
22. Papéis de parede animados: https://android-developers.googleblog.com/2010/02/live-wallpapers.html
23. Documentação da ferramenta de referência (para adb, aapt, ddms): http://developer.android.com/guide/developing/tools/index.html
24. Descrição do arquivo apk do Android: http://developer.android.com/guide/topics/fundamentals.html
25. Arquivos de manifesto: http://developer.android.com/guide/topics/manifest/manifest-intro.html
26. Ferramenta de teste de macaco: https://developer.android.com/studio/test/other-testing-tools/monkey
27. Lista de recursos de hardware Android: http://developer.android.com/reference/android/content/pm/PackageManager.html
28. Suporte para múltiplas telas: 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. Espaço de coordenadas do sensor: http://developer.android.com/reference/android/hardware/SensorEvent.html
32. API Bluetooth: http://developer.android.com/reference/android/bluetooth/package-summary.html
33. Protocolo Push NDEF: http://source.android.com/docs/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 de orientação da câmera: 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. Referência de segurança e permissões do Android: http://developer.android.com/guide/topics/security/security.html
43. Aplicativos para Android: http://code.google.com/p/apps-for-android

Muitos desses recursos são derivados direta ou indiretamente do SDK do Android 2.3 e serão funcionalmente idênticos às informações contidas na documentação desse SDK. Em qualquer caso em que esta Definição de Compatibilidade ou o Conjunto de Testes de Compatibilidade discordem da documentação do SDK, a documentação do SDK será considerada oficial. Quaisquer detalhes técnicos fornecidos nas referências incluídas acima são considerados, por inclusão, como parte desta Definição de Compatibilidade.

3. Programas

A plataforma Android inclui um conjunto de APIs gerenciadas, um conjunto de APIs nativas e um corpo das chamadas APIs "soft", como o sistema Intent e APIs de aplicativos da web. Esta seção detalha as APIs físicas e flexíveis que são essenciais para a compatibilidade, bem como alguns outros comportamentos técnicos e de interface do usuário relevantes. As implementações de dispositivos DEVEM cumprir todos os requisitos desta seção.

3.1. Compatibilidade de API gerenciada

O ambiente de execução gerenciado (baseado em Dalvik) é o principal veículo para aplicativos Android. A interface de programação de aplicativos (API) Android é o conjunto de interfaces da plataforma Android expostas a aplicativos em execução no ambiente de VM gerenciado. As implementações de dispositivos DEVEM fornecer implementações completas, incluindo todos os comportamentos documentados, de qualquer API documentada exposta pelo SDK do Android 2.3 [ Recursos, 4 ].

As implementações de dispositivos NÃO DEVEM omitir APIs gerenciadas, alterar interfaces ou assinaturas de API, desviar-se do comportamento documentado ou incluir operações autônomas, exceto quando especificamente permitido por esta Definição de Compatibilidade.

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

3.2. Compatibilidade de API suave

Além das APIs gerenciadas da Seção 3.1, o Android também inclui uma API "soft" significativa somente em tempo de execução, na forma de itens como Intents, permissões e aspectos semelhantes de aplicativos Android que não podem ser aplicados no tempo de compilação do aplicativo. Esta seção detalha as APIs "soft" e os comportamentos do sistema necessários para compatibilidade com o Android 2.3. As implementações de dispositivos DEVEM atender a todos os requisitos apresentados nesta seção.

3.2.1. Permissões

Os implementadores de dispositivos DEVEM oferecer suporte e impor todas as constantes de permissão, conforme documentado na página de referência de permissão [ Recursos, 5 ]. Observe que a Seção 10 lista requisitos adicionais relacionados ao modelo de segurança do Android.

3.2.2. Parâmetros de construção

As APIs do Android incluem uma série de constantes na classe android.os.Build [ Resources, 6 ] que se destinam a descrever o dispositivo atual. Para fornecer valores consistentes e significativos em todas as implementações de dispositivos, a tabela abaixo inclui restrições adicionais sobre os formatos desses valores aos quais as implementações de dispositivos DEVEM estar em conformidade.

3.2.3. Compatibilidade de intenções

O Android usa Intents para obter integração fraca entre aplicativos. Esta seção descreve os requisitos relacionados aos padrões de Intent que DEVEM ser respeitados pelas implementações de dispositivos. Por "honrado", significa que o implementador do dispositivo DEVE fornecer uma atividade ou serviço Android que especifique um filtro de intenção correspondente e se vincule e implemente o comportamento correto para cada padrão de intenção especificado.

3.2.3.1. Principais intenções do aplicativo

O projeto upstream do Android define uma série de aplicativos principais, como discador telefônico, calendário, agenda de contatos, reprodutor de música e assim por diante. Os implementadores de dispositivos PODEM substituir esses aplicativos por versões alternativas.

No entanto, quaisquer versões alternativas DEVEM respeitar os mesmos padrões de Intenção fornecidos pelo projeto upstream. Por exemplo, se um dispositivo contiver um reprodutor de música alternativo, ele ainda deverá respeitar o padrão de Intent emitido por aplicativos de terceiros para escolher uma música.

Os seguintes aplicativos são considerados aplicativos principais do sistema Android:

• Relógio de mesa
• Navegador
• Calendário
• Calculadora
• Contatos
• E-mail
• Galeria
• Pesquisa Global
• Lançador
• Música
• Configurações

Os principais aplicativos do sistema Android incluem vários componentes de atividade ou serviço que são considerados "públicos". Ou seja, o atributo “android:exported” pode estar ausente, ou pode ter o valor “true”.

Para cada atividade ou serviço definido em um dos principais aplicativos do sistema Android que não esteja marcado como não público por meio de um atributo android:exported com o valor "false", as implementações de dispositivos DEVEM incluir um componente do mesmo tipo implementando o mesmo filtro de Intent padrões como o principal aplicativo do sistema Android.

Em outras palavras, uma implementação de dispositivo PODE substituir os principais aplicativos do sistema Android; no entanto, se isso acontecer, a implementação do dispositivo DEVE suportar todos os padrões de intenção definidos por cada aplicativo principal do sistema Android que está sendo substituído.

3.2.3.2. Substituições de intenção

Como o Android é uma plataforma extensível, os implementadores de dispositivos DEVEM permitir que cada padrão de Intent mencionado na Seção 3.2.3.1 seja substituído por aplicativos de terceiros. O projeto de código aberto Android upstream permite isso por padrão; os implementadores de dispositivos NÃO DEVEM atribuir privilégios especiais ao uso desses padrões de Intenção pelos aplicativos do sistema ou impedir que aplicativos de terceiros se vinculem e assumam o controle desses padrões. Esta proibição inclui especificamente, mas não está limitada a desabilitar a interface do usuário "Seletor", que permite ao usuário selecionar entre vários aplicativos que lidam com o mesmo padrão de Intenção.

3.2.3.3. Namespaces de intenção

Os implementadores de dispositivos NÃO DEVEM incluir nenhum componente Android que honre quaisquer novos padrões de Intent ou Broadcast Intent usando uma ACTION, CATEGORY ou outra string de chave no namespace android.*. Os implementadores de dispositivos NÃO DEVEM incluir nenhum componente Android que honre quaisquer novos padrões de Intent ou Broadcast Intent usando uma ACTION, CATEGORY ou outra string de chave em um espaço de pacote pertencente a outra organização. Os implementadores de dispositivos NÃO DEVEM alterar ou estender nenhum dos padrões de Intent usados ​​pelos aplicativos principais listados na Seção 3.2.3.1.

Esta proibição é análoga àquela especificada para classes de linguagem Java na Seção 3.6.

3.2.3.4. Intenções de transmissão

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

3.3. Compatibilidade de API nativa

O código gerenciado em execução no Dalvik pode chamar o código nativo fornecido no arquivo .apk do aplicativo como um arquivo ELF .so compilado para a arquitetura de hardware do dispositivo apropriada. Como o código nativo é altamente dependente da tecnologia de processador subjacente, o Android define uma série de interfaces binárias de aplicativos (ABIs) no Android NDK, no arquivo docs/CPU-ARCH-ABIS.txt . Se a implementação de um dispositivo for compatível com uma ou mais ABIs definidas, DEVE implementar a compatibilidade com o Android NDK, conforme abaixo.

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

• DEVE incluir suporte para código em execução no ambiente gerenciado para chamar código nativo, usando a semântica padrão Java Native Interface (JNI).
• DEVE ser compatível com a fonte (ou seja, compatível com o cabeçalho) e compatível com o binário (para a ABI) com cada biblioteca necessária na lista abaixo
• DEVE relatar com precisão a Application Binary Interface (ABI) nativa suportada pelo dispositivo, por meio da API android.os.Build.CPU_ABI
• DEVE relatar apenas as ABIs documentadas na versão mais recente do Android NDK, no arquivo docs/CPU-ARCH-ABIS.txt
• DEVE ser construído usando o código-fonte e os arquivos de cabeçalho disponíveis no projeto de código aberto Android upstream

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

• libc (biblioteca C)
• libm (biblioteca matemática)
• Suporte mínimo para C++
• Interface JNI
• liblog (registro do Android)
• libz (compressão Zlib)
• libdl (vinculador dinâmico)
• libGLESv1_CM.so (OpenGL ES 1.0)
• libGLESv2.so (OpenGL ES 2.0)
• libEGL.so (gerenciamento de superfície OpenGL nativo)
• libjnigraphics.so
• libOpenSLES.so (suporte de áudio da Open Sound Library)
• libandroid.so (suporte nativo à atividade do Android)
• Suporte para OpenGL, conforme descrito abaixo

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

A compatibilidade do código nativo é um desafio. Por esta razão, deve ser repetido que os implementadores de dispositivos são MUITO fortemente encorajados a usar as implementações upstream das bibliotecas listadas acima para ajudar a garantir a compatibilidade.

3.4. Compatibilidade Web

Muitos desenvolvedores e aplicativos dependem do comportamento da classe android.webkit.WebView [ Resources, 8 ] para suas interfaces de usuário, portanto, a implementação do WebView deve ser compatível com todas as implementações do Android. Da mesma forma, um navegador completo e moderno é fundamental para a experiência do usuário Android. As implementações de dispositivos DEVEM incluir uma versão de android.webkit.WebView consistente com o software Android upstream e DEVEM incluir um navegador moderno compatível com HTML5, conforme descrito abaixo.

3.4.1. Compatibilidade com WebView

A implementação do Android Open Source usa o mecanismo de renderização WebKit para implementar o android.webkit.WebView . Como não é viável desenvolver um conjunto de testes abrangente para um sistema de renderização da Web, os implementadores de dispositivos DEVEM usar a construção upstream específica do WebKit na implementação do WebView. Especificamente:

• As implementações de android.webkit.WebView das implementações de dispositivos DEVEM ser baseadas na versão 533.1 WebKit da árvore upstream de código-fonte aberto do Android para Android 2.3. Esta compilação inclui um conjunto específico de funcionalidades e correções de segurança para o WebView. Os implementadores de dispositivos PODEM incluir personalizações na implementação do WebKit; no entanto, tais personalizações NÃO DEVEM alterar o comportamento do WebView, incluindo o comportamento de renderização.
• A string do agente do usuário relatada pelo WebView DEVE estar neste formato:
  Mozilla/5.0 (Linux; U; Android $(VERSION); $(LOCALE); $(MODEL) Build/$(BUILD)) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1
  • O valor da string $(VERSION) DEVE ser igual ao valor de android.os.Build.VERSION.RELEASE
  • O valor da string $(LOCALE) DEVE seguir as convenções ISO para código de país e idioma, e DEVE referir-se à localidade atualmente configurada do dispositivo
  • O valor da string $(MODEL) DEVE ser igual ao valor de android.os.Build.MODEL
  • O valor da string $(BUILD) DEVE ser igual ao valor de android.os.Build.ID

O componente WebView DEVE incluir suporte para o máximo possível de HTML5 [ Resources, 9 ]. No mínimo, as implementações de dispositivos DEVEM suportar cada uma destas APIs associadas ao HTML5 no WebView:

• cache de aplicativo/operação offline [ Recursos, 10 ]
• a tag <video> [ Recursos, 11 ]
• geolocalização [ Recursos, 12 ]

Além disso, as implementações de dispositivos DEVEM oferecer suporte à API de armazenamento na web HTML5/W3C [ Recursos, 13 ] e DEVEM oferecer suporte à API HTML5/W3C IndexedDB [ Recursos, 14 ]. Observe que, à medida que os órgãos de padrões de desenvolvimento web estão fazendo a transição para favorecer o IndexedDB em vez do armazenamento na web, espera-se que o IndexedDB se torne um componente obrigatório em uma versão futura do Android.

As APIs HTML5, como todas as APIs JavaScript, DEVEM ser desabilitadas por padrão em um WebView, a menos que o desenvolvedor as ative explicitamente por meio das APIs Android usuais.

3.4.2. Compatibilidade do navegador

As implementações de dispositivos DEVEM incluir um aplicativo de navegador independente para navegação geral do usuário na web. O navegador independente PODE ser baseado em uma tecnologia de navegador diferente do WebKit. No entanto, mesmo que um aplicativo de navegador alternativo seja usado, o componente android.webkit.WebView fornecido para aplicativos de terceiros DEVE ser baseado no WebKit, conforme descrito na Seção 3.4.1.

As implementações PODEM enviar uma string de agente de usuário personalizada no aplicativo de navegador independente.

O aplicativo de navegador independente (seja baseado no aplicativo WebKit Browser upstream ou em um substituto de terceiros) DEVE incluir suporte para o máximo de HTML5 [ Resources, 9 ] quanto possível. No mínimo, as implementações de dispositivos DEVEM suportar cada uma destas APIs associadas ao HTML5:

• cache de aplicativo/operação offline [ Recursos, 10 ]
• a tag <video> [ Recursos, 11 ]
• geolocalização [ Recursos, 12 ]

Além disso, as implementações de dispositivos DEVEM oferecer suporte à API de armazenamento na web HTML5/W3C [ Recursos, 13 ] e DEVEM oferecer suporte à API HTML5/W3C IndexedDB [ Recursos, 14 ]. Observe que, à medida que os órgãos de padrões de desenvolvimento web estão fazendo a transição para favorecer o IndexedDB em vez do armazenamento na web, espera-se que o IndexedDB se torne um componente obrigatório em uma versão futura do Android.

3.5. Compatibilidade comportamental da API

Os comportamentos de cada um dos tipos de API (gerenciado, flexível, nativo e web) devem ser consistentes com a implementação preferida do projeto de código aberto Android upstream [ Recursos, 3 ]. Algumas áreas específicas de compatibilidade são:

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

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

3.6. Namespaces de API

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

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

As modificações proibidas incluem:

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

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

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

Se um implementador de dispositivo propor melhorar um dos namespaces de pacote acima (como adicionando novas funcionalidades úteis a uma API existente ou adicionando uma nova API), o implementador DEVE visitar source.android.com e iniciar o processo para contribuir com alterações e código, de acordo com as informações desse site.

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

3.7. Compatibilidade de Máquina Virtual

As implementações de dispositivos DEVEM suportar a especificação completa de bytecode Dalvik Executable (DEX) e a semântica da Dalvik Virtual Machine [ Recursos, 15 ].

Implementações de dispositivos com telas classificadas como de média ou baixa densidade DEVEM configurar a Dalvik para alocar pelo menos 16 MB de memória para cada aplicação. Implementações de dispositivos com telas classificadas como de alta densidade ou extra-alta densidade DEVEM configurar a Dalvik para alocar pelo menos 24 MB de memória para cada aplicação. Observe que as implementações de dispositivos PODEM alocar mais memória do que esses números.

3.8. Compatibilidade da interface do usuário

A plataforma Android inclui algumas APIs de desenvolvedor que permitem que os desenvolvedores se conectem à interface de usuário do sistema. As implementações de dispositivos DEVEM incorporar essas APIs de UI padrão nas interfaces de usuário personalizadas que desenvolvem, conforme explicado abaixo.

3.8.1. Widgets

O Android define um tipo de componente e API e ciclo de vida correspondentes que permitem que os aplicativos exponham um "AppWidget" ao usuário final [ Recursos, 16 ]. A versão de referência do Android Open Source inclui um aplicativo Launcher que inclui elementos da interface do usuário que permitem ao usuário adicionar, visualizar e remover AppWidgets da tela inicial.

Os implementadores de dispositivos PODEM substituir uma alternativa ao Launcher de referência (ou seja, tela inicial). Iniciadores alternativos DEVEM incluir suporte integrado para AppWidgets e expor elementos da interface do usuário para adicionar, configurar, visualizar e remover AppWidgets diretamente no Iniciador. Lançadores alternativos PODEM omitir esses elementos da interface do usuário; entretanto, se forem omitidos, o implementador do dispositivo DEVE fornecer um aplicativo separado, acessível a partir do Launcher, que permita aos usuários adicionar, configurar, visualizar e remover AppWidgets.

3.8.2. Notificações

O Android inclui APIs que permitem aos desenvolvedores notificar os usuários sobre eventos notáveis ​​[ Recursos, 17 ]. Os implementadores de dispositivos DEVEM fornecer suporte para cada classe de notificação assim definida; especificamente: sons, vibração, luz e barra de status.

Além disso, a implementação DEVE renderizar corretamente todos os recursos (ícones, arquivos de som, etc.) previstos nas APIs [ Recursos, 18 ] ou no guia de estilo de ícones da Barra de Status [ Recursos, 19 ]. Os implementadores de dispositivos PODEM fornecer uma experiência de usuário alternativa para notificações do que aquela fornecida pela implementação de referência do Android Open Source; no entanto, tais sistemas de notificação alternativos DEVEM apoiar os recursos de notificação existentes, como acima.

3.8.3. Procurar

O Android inclui APIs [ Resources, 20 ] que permitem aos desenvolvedores incorporar pesquisas em seus aplicativos e expor os dados de seus aplicativos na pesquisa global do sistema. De modo geral, essa funcionalidade consiste em uma interface de usuário única para todo o sistema que permite aos usuários inserir consultas, exibir sugestões à medida que os usuários digitam e exibir resultados. As APIs do Android permitem que os desenvolvedores reutilizem essa interface para fornecer pesquisa em seus próprios aplicativos e permitem que os desenvolvedores forneçam resultados para a interface de usuário de pesquisa global comum.

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

As implementações de dispositivos PODEM fornecer interfaces de usuário de pesquisa alternativas, mas DEVEM incluir um botão de pesquisa dedicado rígido ou flexível, que pode ser usado a qualquer momento em qualquer aplicativo para invocar a estrutura de pesquisa, com o comportamento previsto na documentação da API.

3.8.4. Torradas

Os aplicativos podem usar a API "Toast" (definida em [ Recursos, 21 ]) para exibir strings curtas não modais para o usuário final, que desaparecem após um breve período de tempo. As implementações de dispositivos DEVEM exibir brindes de aplicativos para usuários finais de forma de alta visibilidade.

3.8.5. Papel de parede animados

O Android define um tipo de componente e API e ciclo de vida correspondentes que permitem que os aplicativos exponham um ou mais "Live Wallpapers" ao usuário final [ Recursos, 22 ]. Papéis de parede animados são animações, padrões ou imagens semelhantes com recursos de entrada limitados que são exibidos como papel de parede, atrás de outros aplicativos.

O hardware é considerado capaz de executar papéis de parede animados de forma confiável se puder executar todos os papéis de parede animados, sem limitações de funcionalidade, a uma taxa de quadros razoável, sem efeitos adversos em outros aplicativos. Se limitações no hardware fizerem com que os papéis de parede e/ou aplicativos travem, funcionem mal, consumam energia excessiva da CPU ou da bateria ou sejam executados com taxas de quadros inaceitavelmente baixas, o hardware será considerado incapaz de executar papéis de parede ao vivo. Por exemplo, alguns papéis de parede animados podem usar um contexto Open GL 1.0 ou 2.0 para renderizar seu conteúdo. O papel de parede ao vivo não será executado de forma confiável em hardware que não suporta vários contextos OpenGL porque o uso do papel de parede ao vivo de um contexto OpenGL pode entrar em conflito com outros aplicativos que também usam um contexto OpenGL.

Implementações de dispositivos capazes de executar papéis de parede animados de maneira confiável, conforme descrito acima, DEVEM implementar papéis de parede animados. As implementações de dispositivos determinadas a não executar papéis de parede animados de forma confiável, conforme descrito acima, NÃO DEVEM implementar papéis de parede animados.

4. Compatibilidade de pacotes de aplicativos

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

Implementações de dispositivos:

• 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

Implementações de dispositivos:

• 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

Implementações de dispositivos:

• 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

  Implementações de dispositivos:

  • 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. Permissões

  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.