Definizione di compatibilità con Android 4.1

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Definizione di compatibilità con Android 4.1
Revisione 3
Ultimo aggiornamento: 24 giugno 2013
Copyright © 2012, Google Inc. Tutti i diritti riservati.
compatibilità@android.com
Sommario
1. Introduzione
2. Risorse
3. Software
3.1. Compatibilità API invecchiata per uomo
3 .2. Compatibilità API morbida
3.2.1. Permessi
3 .2.2. Costruisci parametri rs
3 .2.3. Compatibilità delle intenzioni
3.2.3.1. Scopi dell'applicazione principale
3 .2.3.2. Sostituzioni di intenti
3 .2.3.3. Spazi dei nomi di intenti
3 .2.3.4. Intenzioni di trasmissione
3.3. Compatibilità API nativa
3.3.1 Interfacce binarie dell'applicazione
3.4. Compatibilità Web
3.4.1. Compatibilità WebView
3.4.2. Compatibilità del browser
3.5. Compatibilità comportamentale API
3.6. Spazi dei nomi API
3.7. Compatibilità con macchine virtuali
3 .8. Compatibilità dell'interfaccia utente
3.8.1. Widget
3.8.2. Notifiche
3 .8.3. Ricerca
3 .8.4. Brindisi
3 .8.5. Temi
3 .8.6. Documenti in diretta Wal
3 .8.7. Visualizzazione dell'applicazione recente
3 .8.8. Impostazioni di gestione dell'input
3 .8.9. Blocco schermo telecomando
3.9 Amministrazione del dispositivo
3.10 Accessibilità
3 .11 Sintesi vocale
4. Compatibilità dell'imballaggio dell'applicazione
5. Compatibilità multimediale
5.1. Codec multimediali
5.2. Codifica video
5.3. Registrazione audio
5.4. Latenza audio
5 .5. Protocolli di rete
6. Compatibilità con gli strumenti dello sviluppatore
7. Compatibilità hardware
7 .1. Display e grafica
7.1.1. Configurazione dello schermo
7.1.2. Visualizza metriche
7.1.3. Orientamento schermo n
7 .1.4. Accelerazione grafica 2D e 3D
7 .1.5. Modalità di compatibilità delle applicazioni legacy
7 .1.6. Tipi di schermo
7 .1.7. Tecnologia dello schermo
7.2. Dispositivi di immissione
7 .2.1. Tastiera del computer
7 .2.2. Navigazione senza tocco
7.2.3. Tasti di navigazione
7.2.4. Ingresso touchscreen
7.2.5. Ingresso tocco falso
7.2.6. Microfono
7.3. Sensori
7 .3.1. Accelerometro

7.3.1. Accelerometro
7 .3.2. Magnetometro
7 .3.3. GPS
7 .3.4. Giroscopio
7 .3.5. Barometro
7 .3.6. Termometro
7 .3.7. Fotometro
7 .3.8. Sensore di prossimità
7 .4. Connettività dati
7.4.1. Telefonia
7.4.2. IEEE 802.11 (WiFi)
7.4.2.1. Wi-Fi diretto
7.4.3. Bluetooth
7.4.4. Near Field Communication
7 .4.5. Capacità di rete minima
7.5. telecamere
7.5.1. Fotocamera posteriore
7 .5.2. Fotocamera frontale
7 .5.3. Comportamento dell'API della fotocamera
7 .5.4. Orientamento della fotocamera
7.6. Memoria e archiviazione
7.6.1. Memoria e archiviazione minime
7 .6.2. Archiviazione condivisa dell'applicazione
7.7. USB
8. Compatibilità delle prestazioni
9. Compatibilità del modello di sicurezza
9.1. Permessi
9 .2. UID e isolamento del processo
9 .3. Autorizzazioni del file system
9.4. Ambienti di esecuzione alternativi
10. Test di compatibilità del software
10.1. Suite di test di compatibilità
10.2. Verificatore CTS
10.3. Applicazioni di riferimento
11. Software aggiornabile
12. Contattaci
Appendice A - Procedura di test Bluetooth

1. Introduzione
Questo documento enumera i requisiti che devono essere soddisfatti affinché i dispositivi lo facciano
essere compatibile con Android 4.1.
L'uso di "must", "must not", "required", "shal", "shal not", "dovrebbe", "non dovrebbe",
"consigliato", "maggio" e "facoltativo" è conforme allo standard IETF definito in RFC2119
[ Risorse, 1].
Come utilizzato in questo documento, un "implementatore del dispositivo" o "implementatore" è una persona o
organizzazione che sviluppa una soluzione hardware/software con Android 4.1. Un dispositivo
implementazione" o "implementazione" è la soluzione hardware/software così sviluppata.
Per essere considerato compatibile con Android 4.1, le implementazioni del dispositivo DEVONO soddisfare
i requisiti presentati nella presente Definizione di compatibilità, compresi eventuali documenti
incorporato tramite riferimento.
Laddove questa definizione o i test software descritti nella Sezione 10 tacciano,
ambiguo o incompleto, è responsabilità dell'implementatore del dispositivo garantire
compatibilità con le implementazioni esistenti.
Per questo motivo, il progetto Android Open Source [Risorse, 3] è sia il riferimento
e implementazione preferita di Android. Gli implementatori dei dispositivi sono forti
incoraggiati a basare le loro implementazioni nella misura più ampia possibile sul
codice sorgente "upstream" disponibile da Android Open Source Project. Mentre alcuni
i componenti possono ipoteticamente essere sostituiti con implementazioni alternative questo
la pratica è fortemente sconsigliata, poiché il superamento dei test del software diverrà
sostanziale e più difficile. È responsabilità dell'implementatore garantire un comportamento completo
compatibilità con l'implementazione standard di Android, incluso e oltre il
Suite di test di compatibilità. Infine, si noti che alcune sostituzioni di componenti e
le modifiche sono espressamente vietate dal presente documento.
2. Risorse
1. Livelli di requisiti IETF RFC2119: http://www.ietf.org/rfc/rfc2119.txt
2. Panoramica del programma di compatibilità Android:
http://source.android.com/compatibility/index.html
3. Progetto Open Source Android: http://source.android.com/
4. Definizioni API e documentazione:
http://developer.android.com/refe rence/packages.html
5. Riferimento autorizzazioni Android:
http://developer.android.com/reference/android/Manifest.p ermission.html
6. Riferimento android.os.Build:
http://developer.android.com/reference/android/os/Build.html
7. Stringhe di versione consentite per Android 4.1:
http://source.android.com/compatibility/4.1/versions.html
8. Renderscript:
http://developer.android.com/guide/topics/graphics/rendersc ript.html
9. Accelerazione hardware:
http://developer.android.com/guide/topics/graphics/hardware-accel.html
10. classe android.webkit.WebView:
http://developer.android.com/reference/android/webkit/WebView.html
11. HTML5: http://www.whatwg.org/specs/web-apps/current-work/multipage/
12. Funzionalità offline HTML5: http://dev.w3.org/html5/spec/Overview.html#offline
13. Tag video HTML5: http://dev.w3.org/html5/spec/Overview.html#video
14. API di geolocalizzazione HTML5/W3C: http://www.w3.org/TR/geolocation-API/
15. Webdatabase HTML5/W3C A PI: http://www.w3.org/TR/webdatabase/
16. API dDB dell'indice HTML5/W3C: http://www.w3.org/TR/IndexedDB/
17. Specifica della Dalvik Virtual Machine: disponibile nel codice sorgente di Android, all'indirizzo
dalvik/docs
18. Widget app:
http://developer.android.com/guide/practices/ui_guidelines/widget_design.html
19. Notifiche:
http://developer.android.com/guide/topics/ui/notifiers/notifications.html
20. Risorse per l'applicazione: http://code.google.com/android/reference/available-
risorse.html
21. Guida allo stile dell'icona della barra di stato:
http://developer.android.com/guide/practices/ui_guidelines/icon_design_status_b ar.html
22. Gestore ricerca:
http://developer.android.com/reference/android/app/SearchManager.html
23. Brindisi: http://developer.android.com/reference/android/widget/Toast.html
24. Temi: http://developer.android.com/guide/topics/ui/themes.html

25. Classe R.style: h ttp://developer.android.com/reference/android/R.style.html
26. Documenti Live Wal: http://developer.android.com/resources/articles/live-
wal paper.html
27. Amministrazione del dispositivo Android:
http://developer.android.com/guide/topics/admin/device-admin.html
28. classe android.app.admin.DevicePolicyManager:
http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html
29. API del servizio di accessibilità Android:
http://developer.android.com/reference/android/accessibilityservice/package-
sommario.html
30. API di accessibilità Android:
http://developer.android.com/reference/android/view/accessibility/package-
sommario.html
31. Progetto Eyes Free: http://code.google.com/p/eyes-free
32. API di sintesi vocale :
http://developer.android.com/reference/android/speech/tts/package-
sommario.html
33. Documentazione dello strumento di riferimento (per adb, aapt, ddms):
http://developer.android.com/guide/developing/tools/index.html
34. Descrizione del file apk di Android:
http://developer.android.com/guide/topics/fundamentals.html
35. File manifest: http://developer.android.com/guide/topics/manifes t/manifest-
intro.html
36. Strumento di test delle scimmie:
http://developer.android.com/guide/developing/tools/monkey.html
37. Classe Android android.content.pm.PackageManager e caratteristiche hardware
Elenco:
http://developer.android.com/reference/android/content/pm/PackageManager.html
38. Supporto di più schermi:
http://developer.android.com/guide/practices/screens_support.html
39. android.util.DisplayMetrics:
http://developer.android.com/reference/android/util/DisplayMetrics.html
40. Android.content.res.Configurazione:
http://developer.android.com/reference/android/content/res/Configuration.htm l
41. android.hardware.SensorEvent:
http://developer.android.com/reference/android/hardware/SensorEvent.html
42. API Bluetooth:
http://developer.android.com/reference/android/bluetooth/package-summary.html
43. Protocollo push NDEF: http://source.android.com/compatibility/ndef-push-
protocollo.pdf
44. MIFARE MF1S503X: http://www.nxp.com/documents/data_sheet/MF1S503x.p df
45. MIFARE MF1S703X: http://www.nxp.com/documents/data_sheet/MF1S703x.p df
46. ​​MIFARE MF0ICU1 : http://www.nxp.com/documents/data_sheet/MF0ICU1.pdf
47. MIFARE MF0ICU2:
http://www.nxp.com/d ocuments/short_data_sheet/MF0ICU2_SDS.pdf
48. MIFARE AN130511:
http://www.nxp.com/documents/application_note/AN130511.pdf
49. MIFARE AN130411:
http://www.nxp.com/documents/application_note/AN130411.pdf
50. API di orientamento della fotocamera:
http://developer.android.com/reference/android/hardware/Camera.html#setDisplayOrientation(int)
51. Android.hardware.Fotocamera:
http://developer.android.com/reference/android/hardware/Camera.html
52. Accessori Android aperti:
http://developer.android.com/guide/topics/usb/accessory.html
53. API host USB: http://developer.android.com/guide/topics/usb/host.html
54. Riferimento per la sicurezza e le autorizzazioni Android:
http://developer.android.com/guide/topics/security/security.html
55. App per Android : http://code.google.com/p/apps-for-android
56. classe android.app.DownloadManager:
http://developer.android.com/reference/android/app/DownloadMana ger.html
57. Trasferimento file Android : http://www.android.com/filetransfer
58. Formati multimediali Android: http://developer.android.com/guide/appendice/media-
formats.html
59. Protocollo D raft HTTP Live Streaming: http://tools.ietf.org/html/d raft-pantos-http-
live-streaming-03
60. Consegna della connessione NFC: http://www.nfc-
forum.org/specs/spec_list/#conn_handover
61. Accoppiamento semplice sicuro Bluetooth tramite NFC: http://www.nfc-
forum.org/resources/AppDocs/NFCForum_AD_BTSSP_1_0.pdf
62. API multicast Wi-Fi:
http://developer.android.com/reference/android/net/wifi/WifiManager.MulticastLock.html

63. Assistenza all'azione:
http://developer.android.com/reference/android/content/Intent.html#ACTION_ASSIST
64. Specifiche di ricarica USB:
http://www.usb.org/developers/devclass_docs/USB_Battery_Charging_1.2.pdf
65. Android Beam: h ttp://developer.android.com/guide/topics/nfc/nfc.html
66. Audio USB Android:
http://developer.android.com/reference/android/hardware/usb/UsbConstants.html#USB_CLASS_AUDIO
67. Impostazioni di condivisione NFC Android:
http://developer.android.com/reference/android/provider/Settings.html#ACTION_NFCSHARING_SETTINGS
68. Wifi diretto (WiFi P2P):
http://developer.android.com/reference/android/net/wifi/p2p/WifiP2pManager.html
69. Cliente di controllo remoto multimediale:
http://developer.android.com/reference/android/media/RemoteControlClient.html
70. API di eventi di movimento:
http://developer.android.com/reference/android/view/MotionEvent.html
71. Configurazione input tocco: http://source.android.com/tech/input/touch-
dispositivi.html
Molte di queste risorse derivano direttamente o indirettamente dall'SDK di Android 4.1,
e sarà funzionalmente identico alle informazioni nella documentazione di tale SDK. In qualunque
casi in cui questa Definizione di compatibilità o Compatibility Test Suite non sono d'accordo
la documentazione SDK, la documentazione SDK è considerata autorevole. Qualunque
i dettagli tecnici forniti nei riferimenti sopra inclusi sono presi in considerazione da
inclusione a far parte di questa definizione di compatibilità.
3. Software
3.1. Compatibilità API gestita
L'ambiente di esecuzione gestito (basato su Dalvik) è il veicolo principale per Android
applicazioni. L'interfaccia di programmazione dell'applicazione Android (API) è l'insieme di
Interfacce della piattaforma Android esposte alle applicazioni in esecuzione nella macchina virtuale gestita
ambiente. Le implementazioni dei dispositivi DEVONO fornire implementazioni complete,
compresi tutti i comportamenti documentati, di qualsiasi API documentata esposta da Android
4.1 SDK [Risorse, 4].
Le implementazioni dei dispositivi NON DEVONO omettere le API gestite, alterare le interfacce API o
firme, deviare dal comportamento documentato o includere no-op, tranne dove
specificamente consentito dalla presente definizione di compatibilità.
Questa definizione di compatibilità consente alcuni tipi di hardware per i quali Android
include le API che devono essere omesse dalle implementazioni del dispositivo. In questi casi, le API DEVONO
essere comunque presente e comportarsi in modo ragionevole. Vedere la Sezione 7 per i dettagli
requisiti per questo scenario.
3.2. Compatibilità API morbida
Oltre alle API gestite della Sezione 3.1, Android include anche un significativo
API "soft" di solo runtime, sotto forma di elementi come intenti, autorizzazioni e
aspetti simili delle applicazioni Android che non possono essere applicati durante la compilazione dell'applicazione
volta.
3.2.1. Permessi
Gli implementatori del dispositivo DEVONO supportare e far rispettare tutte le costanti di autorizzazione come
documentato dalla pagina di riferimento dell'autorizzazione [Risorse, 5]. Si noti che la Sezione 10
elenca i requisiti aggiuntivi relativi al modello di sicurezza Android.
3.2.2. Costruisci parametri
Le API Android includono una serie di costanti nella classe android.os.Build
[Risorse, 6] che hanno lo scopo di descrivere il dispositivo corrente. Per fornire coerente,
valori significativi tra le implementazioni del dispositivo, la tabella seguente include ulteriori
restrizioni sui formati di questi valori a cui le implementazioni del dispositivo DEVONO
c onformare.
Parametro
Commenti
La versione del sistema Android attualmente in esecuzione, in formato leggibile dall'uomo. Questo campo DEVE averne uno
android.os.Build.VERSION.RELEASE
dei valori stringa definiti in [Risorse, 7].
La versione del sistema Android attualmente in esecuzione, in un formato accessibile al codice dell'applicazione di terze parti.
android.os.Build.VERSION.SDK
Per Android 4.1, questo campo DEVE avere il valore intero 16.

La versione del sistema Android attualmente in esecuzione, in un formato accessibile al codice dell'applicazione di terze parti.
android.os.Build.VERSION.SDK_INT
Per Android 4.1, questo campo DEVE avere il valore intero 16.
Un valore scelto dall'implementatore del dispositivo che designa la build specifica dell'Android attualmente in esecuzione
sistema, in formato leggibile. Questo valore NON DEVE essere riutilizzato per diverse build messe a disposizione
android.os.Build.VERSION.INCREMENTAL
utenti finali. Un uso tipico di questo campo è indicare quale numero di build o identificatore di modifica del controllo del codice sorgente era
utilizzato per generare la build. Non ci sono requisiti sul formato specifico di questo campo, tranne che DEVE
NON essere null o la stringa vuota ("").
Un valore scelto dall'implementatore del dispositivo che identifica l'hardware interno specifico utilizzato dal dispositivo, in
formato leggibile dall'uomo. Un possibile utilizzo di questo campo è per indicare la specifica revisione dell'alimentazione della scheda
android.os.Build.BOARD
il dispositivo. Il valore di questo campo DEVE essere codificabile come ASCI a 7 bit e corrispondere all'espressione regolare
"^[a-zA-Z0-9.,_-]+$".
Un valore scelto dall'implementatore del dispositivo che identifica il nome dell'azienda, organizzazione, persona, ecc.
che ha prodotto il dispositivo, in formato leggibile dall'uomo. Un possibile utilizzo di questo campo è quello di indicare l'OEM
android.os.Build.BRAND
e/o vettore che ha venduto il dispositivo. Il valore di questo campo DEVE essere codificabile come ASCI a 7 bit e corrispondere a
espressione regolare "^[a-zA-Z0-9.,_-]+$".
Il nome del set di istruzioni (tipo di CPU + convenzione ABI) del codice nativo. Vedere Sezione 3.3: API nativa
android.os.Build.CPU_ABI
Compatibilità.
Il nome del secondo set di istruzioni (tipo di CPU + convenzione ABI) del codice nativo. Vedi Sezione 3.3: Nativo
android.os.Build.CPU_ABI2
Compatibilità AP I.
V alore scelto dall'implementatore del dispositivo che identifica la specifica configurazione o revisione della scocca
android.os.Build.DEVICE
(talvolta chiamato "design industriale") del dispositivo. Il valore di questo campo DEVE essere codificabile come 7 bit
ASCI e confronta l'espressione regolare "^[a-zA-Z0-9.,_-]+$".
Una stringa che identifica in modo univoco questa build. DOVREBBE essere ragionevolmente leggibile dall'uomo. DEVE seguire questo
modello:
$(MARCHIO)/$(PRODOTTO)/$(DISPOSITIVO):$(VERSIONE.RELEASE)/$(ID)/$(VERSIONE.INCREMENTALE):$(TIPO)/$(TAGS)
Per esempio:
android.os.Build.FINGERPRINT
acme/mydevice/generic:4.1/JRN53/3359:userdebug/test-keys
L'impronta digitale NON DEVE includere spazi bianchi. Se sono presenti altri campi inclusi nel modello sopra
caratteri di spazio bianco, DEVONO essere sostituiti nell'impronta digitale di build con un altro carattere, come il
carattere di sottolineatura ("_"). Il valore di questo campo DEVE essere codificabile come ASCI a 7 bit.
Il nome dell'hardware (dalla riga di comando del kernel o /proc). DOVREBBE essere ragionevolmente umano-
android.os.Build.HARDWARE
leggibile. Il valore di questo campo DEVE essere codificabile come ASCI a 7 bit e corrispondere all'espressione regolare "^[a-
zA-Z0-9.,_-]+$".
Una stringa che identifica in modo univoco l'host su cui è stata costruita la build, in un formato leggibile dall'uomo. Non ci sono
android.os.Build.HOST
requisiti sul formato specifico di questo campo, tranne per il fatto che NON DEVE essere null o la stringa vuota ("").
Un identificatore scelto dall'implementatore del dispositivo per fare riferimento a una versione specifica, in formato leggibile dall'uomo. Questo
il campo può essere lo stesso di android.os.Build.VERSION.INCREMENTAL, ma DOVREBBE essere un valore sufficientemente
android.os.Build.ID
significativo per gli utenti finali per distinguere tra build di software. Il valore di questo campo DEVE essere codificabile
come ASCI a 7 bit e corrisponde all'espressione regolare "^[a-zA-Z0-9.,_-]+$".
Il nome commerciale del produttore di apparecchiature originali (OEM) del prodotto. Non ci sono requisiti
android.os.Build.PRODUTTORE
il formato specifico di questo campo, tranne che NON DEVE essere null o la stringa vuota ("").
Un valore scelto dall'implementatore del dispositivo contenente il nome del dispositivo noto all'utente finale. Questo
android.os.Build.MODEL
DOVREBBE essere lo stesso nome con cui il dispositivo viene commercializzato e venduto agli utenti finali. Non ci sono
requisiti sul formato specifico di questo campo, tranne per il fatto che NON DEVE essere null o la stringa vuota ("").
Un valore scelto dall'implementatore del dispositivo contenente il nome di sviluppo o il nome in codice del prodotto
android.os.Build.PRODUCT
(SKU). DEVE essere leggibile dall'uomo, ma non è necessariamente destinato alla visualizzazione da parte degli utenti finali. Il valore di questo
il campo DEVE essere codificabile come ASCI a 7 bit e corrispondere all'espressione regolare "^[a-zA-Z0-9.,_-]+$".
Un numero di serie dell'hardware, se disponibile. Il valore di questo campo DEVE essere codificabile come ASCI a 7 bit e corrispondere
android.os.Build.SERIAL
l'espressione regolare "^([a-zA-Z0-9]{0,20})$".
Un elenco separato da virgole di tag scelti dall'implementatore del dispositivo che distinguono ulteriormente la build. Per
android.os.Build.TAGS
esempio, "non firmato, debug". Il valore di questo campo DEVE essere codificabile come ASCI a 7 bit e corrispondere al normale
espressione "^[a-zA-Z0-9.,_-]+$".
android.os.Build.TIME
Un valore che rappresenta il timestamp di quando si è verificata la compilazione.
Un valore scelto dall'implementatore del dispositivo che specifica la configurazione di runtime della build. Questo campo
DOVREBBE avere uno dei valori corrispondenti alle tre tipiche configurazioni di runtime di Android: "utente",
android.os.Build.TYPE
"userdebug" o "eng". Il valore di questo campo DEVE essere codificabile come ASCI a 7 bit e corrispondere al normale
espressione "^[a-zA-Z0-9.,_-]+$".
Un nome o un ID utente dell'utente (o utente automatizzato) che ha generato la build. Non ci sono requisiti
android.os.Build.USER
il formato specifico di questo campo, tranne che NON DEVE essere null o la stringa vuota ("").
3.2.3. Compatibilità delle intenzioni
Le implementazioni del dispositivo DEVONO onorare il sistema di intenti ad accoppiamento libero di Android, come

descritto nelle sezioni seguenti. Per "onorato", si intende l'implementatore del dispositivo
DEVE fornire un'attività o un servizio Android che specifichi un filtro di intenti corrispondente e
si lega e implementa il comportamento corretto per ogni modello di intento specificato.
3.2.3.1. Scopi dell'applicazione di base
Il progetto a monte di Android definisce una serie di applicazioni principali, come contatti,
calendario, galleria di foto, lettore musicale e così via. Gli implementatori del dispositivo POSSONO sostituire
queste applicazioni con versioni alternative.
Tuttavia, tali versioni alternative DEVONO rispettare gli stessi modelli di intenti forniti
dal progetto a monte. Ad esempio, se un dispositivo contiene un lettore musicale alternativo,
deve comunque rispettare lo schema di intenti emesso da applicazioni di terze parti per scegliere un brano.
Le seguenti applicazioni sono considerate applicazioni di base del sistema Android:
Orologio da tavolo
Browser
Calendario
Contatti
Galleria
Ricerca globale
Lanciatore
Musica
Impostazioni
Le applicazioni principali del sistema Android includono vari componenti di attività o servizi
che sono considerati "pubblici". Cioè, l'attributo "android:exported" potrebbe essere assente o
può avere il valore "vero".
Per ogni attività o servizio definito in una delle app principali del sistema Android che non lo è
contrassegnato come non pubblico tramite un attributo android:exported con il valore "false", dispositivo
le implementazioni DEVONO includere un componente dello stesso tipo che implementa il
stessi modelli di filtro Intento dell'app di sistema Android principale.
In altre parole, l'implementazione di un dispositivo PUÒ sostituire le app di sistema Android di base;
tuttavia, se lo fa, l'implementazione del dispositivo DEVE supportare tutti i modelli di intenti definiti
dalla sostituzione di ciascuna app di sistema Android principale.
3.2.3.2. Sostituzioni di intenti
Poiché Android è una piattaforma estensibile, le implementazioni dei dispositivi DEVONO consentire ogni intento
pattern a cui si fa riferimento nella Sezione 3.2.3.2 per essere sovrascritto da applicazioni di terze parti. Il
l'implementazione open source di Android a monte lo consente per impostazione predefinita; dispositivo
gli implementatori NON DEVONO attribuire privilegi speciali all'uso di applicazioni di sistema
questi modelli di intenti o impediscono alle applicazioni di terze parti di legarsi e assumere
controllo di questi modelli. Questo divieto include specificamente ma non si limita a
disabilitando l'interfaccia utente "Chooser" che consente all'utente di selezionare tra più
applicazioni che gestiscono tutte lo stesso schema di intenti.
Tuttavia, le implementazioni del dispositivo POSSONO fornire attività predefinite per URI specifici
pattern (es. http://play.google.com) se l'attività predefinita prevede un filtro più specifico
per l'URI dei dati. Ad esempio, un filtro di intent che specifica l'URI dei dati
"http://www.android.com" è più specifico del filtro del browser per "http://". Dispositivo
le implementazioni DEVONO fornire un'interfaccia utente per consentire agli utenti di modificare l'attività predefinita
per intenti.
3.2.3.3. Spazi dei nomi di intenti
Le implementazioni del dispositivo NON DEVONO includere alcun componente Android che ne rispetti
nuovi modelli di intenti o trasmissioni di intenti utilizzando una chiave ACTION, CATEGORY o un'altra chiave
stringa nello spazio dei nomi android.* o com.android.*. Gli implementatori di dispositivi NON DEVONO
includere tutti i componenti Android che rispettano eventuali nuovi modelli di intenti o di intenti di trasmissione
utilizzando una stringa di chiave ACTION, CATEGORY o un'altra chiave in uno spazio di pacchetto a cui appartiene
un'altra organizzazione. Gli implementatori del dispositivo NON DEVONO alterare o estendere alcuno degli intenti
modelli utilizzati dalle app principali elencate nella Sezione 3.2.3.1. Implementazioni del dispositivo MAGGIO
includere modelli di intenti utilizzando spazi dei nomi chiaramente e ovviamente associati ai loro
propria organizzazione.
Questo divieto è analogo a quello specificato per le classi di linguaggio Java nella Sezione
3.6.
3.2.3.4. Intenzioni di trasmissione
Le applicazioni di terze parti si affidano alla piattaforma per trasmettere determinati intenti per notificarli

di cambiamenti nell'ambiente hardware o software. Dispositivi compatibili con Android
DEVE trasmettere gli intenti di trasmissione pubblica in risposta a un sistema appropriato
eventi. Gli intenti di trasmissione sono descritti nella documentazione dell'SDK.
3.3. Compatibilità API nativa
3.3.1 Interfacce binarie dell'applicazione
Il codice gestito in esecuzione in Dalvik può richiamare il codice nativo fornito nell'applicazione
.apk come file ELF .so compilato per l'architettura hardware del dispositivo appropriata.
Poiché il codice nativo dipende fortemente dalla tecnologia del processore sottostante, Android
definisce un numero di Application Binary Interfaces (ABI) in Android NDK, nel file
documenti/CPU-ARCH-ABIS.html. Se l'implementazione di un dispositivo è compatibile con uno o più
definiti ABI, DOVREBBE implementare la compatibilità con Android NDK, come di seguito.
Se l'implementazione di un dispositivo include il supporto per un ABI Android,:
DEVE includere il supporto per il codice in esecuzione nell'ambiente gestito da chiamare
codice nativo, utilizzando la semantica JNI (Java Native Interface) standard.
DEVE essere compatibile con la sorgente (cioè compatibile con l'intestazione) e compatibile con il binario (per
l'ABI) con ciascuna libreria richiesta nell'elenco seguente
DEVE riportare accuratamente l'interfaccia binaria dell'applicazione nativa (ABI) supportata
dal dispositivo, tramite l'API Android.os.Build.CPU_ABI
DEVE segnalare solo gli ABI documentati nell'ultima versione di Android
NDK, nel file docs/CPU-ARCH-ABIS.txt
DOVREBBE essere compilato utilizzando il codice sorgente e i file di intestazione disponibili nel file
progetto open source Android a monte
Le seguenti API di codice nativo DEVONO essere disponibili per le app che includono codice nativo:
libc (libreria C)
libm (libreria matematica)
Supporto minimo per C++
Interfaccia JNI
liblog (registrazione Android)
libz (compressione Zlib)
libdl (linker dinamico)
libGLESv1_CM.so (OpenGL ES 1.0)
libGLESv2.so (OpenGL ES 2.0)
libEGL.so (gestione nativa della superficie OpenGL)
libjnigraphics.so
libOpenSLES.so (supporto audio OpenSL ES 1.0.1)
libOpenMAXAL.so (supporto OpenMAX AL 1.0.1)
libandroid.so (supporto nativo per attività Android)
Supporto per OpenGL, come descritto di seguito
Tieni presente che le versioni future di Android NDK potrebbero introdurre il supporto per ulteriori
ABI. Se l'implementazione di un dispositivo non è compatibile con un ABI predefinito esistente, esso
NON DEVE segnalare il supporto per qualsiasi ABI al .
La compatibilità del codice nativo è impegnativa. Per questo motivo va ripetuto
gli implementatori di dispositivi sono MOLTO fortemente incoraggiati a utilizzare l'upstream
implementazioni delle librerie sopra elencate per garantire la compatibilità.
3.4. Compatibilità Web
3.4.1. Compatibilità WebView
L'implementazione Android Open Source utilizza il motore di rendering WebKit per
implementare android.webkit.WebView. Perché non è possibile sviluppare a
suite di test completa per un sistema di rendering web, che gli implementatori di dispositivi DEVONO utilizzare
la specifica build upstream di WebKit nell'implementazione di WebView. In particolare:
Le implementazioni android.webkit.WebView delle implementazioni del dispositivo DEVONO essere
basato sulla build 534.30 WebKit dall'albero Open Source di Android a monte
per Android 4.1. Questa build include un insieme specifico di funzionalità e sicurezza
correzioni per la visualizzazione Web. Gli implementatori di dispositivi POSSONO includere personalizzazioni a
implementazione del WebKit; tuttavia, tali personalizzazioni NON DEVONO alterare il
comportamento della visualizzazione Web, incluso il comportamento di rendering.
La stringa dell'agente utente riportata da WebView DEVE essere in questo formato:
Mozilla/5.0 (Linux; U; Android $(VERSIONE); $(LOCALE); $(MODELLO)
Build/$(BUILD)) AppleWebKit/534.30 (KHTML, come Gecko) Version/4.1
Mobile Safari/534.30
Il valore della stringa $(VERSION) DEVE essere uguale al valore per

Il valore della stringa $(VERSION) DEVE essere uguale al valore per
android.os.Build.VERSION.RELEASE
Il valore della stringa $(LOCALE) DOVREBBE seguire le convenzioni ISO per
codice paese e lingua, e DOVREBBE fare riferimento all'attuale configurato
locale del dispositivo
Il valore della stringa $(MODEL) DEVE essere uguale al valore per
android.os.Build.MODEL
Il valore della stringa $(BUILD) DEVE essere uguale al valore per
android.os.Build.ID
Le implementazioni del dispositivo POSSONO omettere Mobile nella stringa dell'agente utente
Il componente WebView DOVREBBE includere il supporto per la maggior parte di HTML5
[Risorse, 11] possibile. Come minimo, le implementazioni dei dispositivi DEVONO supportare ciascuna di esse
queste API associate a HTML5 nella visualizzazione Web:
cache dell'applicazione/operazione offline [Risorse, 12]
il tag <video> [Risorse, 13]
geolocalizzazione [Reso urces, 14]
Ulteriori y, le implementazioni del dispositivo DEVONO supportare l'API di archiviazione web HTML5/W3C
[Risorse, 15] e DOVREBBE supportare l'API HTML5/W3C IndexedDB [Risorse,
16]. Si noti che poiché gli organismi per gli standard di sviluppo web stanno passando a favore
IndexedDB su webstorage, IndexedDB dovrebbe diventare un requisito
componente in una versione futura di Android.
Le API HTML5, come tutte le API JavaScript, DEVONO essere disabilitate per impostazione predefinita in una visualizzazione Web,
a meno che lo sviluppatore non li abiliti esplicitamente tramite le solite API Android.
3.4.2. Compatibilità del browser
Le implementazioni del dispositivo DEVONO includere un'applicazione browser standalone per informazioni generali
navigazione web dell'utente. Il browser autonomo PUÒ essere basato su una tecnologia browser
diverso da WebKit. Tuttavia, anche se viene utilizzata un'applicazione browser alternativa, il
Il componente android.webkit.WebView fornito ad applicazioni di terze parti DEVE essere
basato su WebKit, come descritto nella Sezione 3.4.1.
Le implementazioni POSSONO spedire una stringa di user agent personalizzata nel browser autonomo
applicazione.
L'applicazione browser standalone (se basata sul browser WebKit a monte
applicazione o una sostituzione di terze parti) DOVREBBE includere il supporto per la maggior parte di
HTML5 [Risorse, 11] possibile. Come minimo, le implementazioni dei dispositivi DEVONO supportare
ciascuna di queste API associate a HTML5:
cache dell'applicazione/operazione offline [Risorse, 12]
il tag <video> [Risorse, 13]
geolocalizzazione [Risorse, 14]
Ulteriori y, le implementazioni del dispositivo DEVONO supportare l'API di archiviazione web HTML5/W3C
[Risorse, 15] e DOVREBBE supportare l'API HTML5/W3C IndexedDB [Risorse,
16]. Si noti che poiché gli organismi per gli standard di sviluppo web stanno passando a favore
IndexedDB su webstorage, IndexedDB dovrebbe diventare un requisito
componente in una versione futura di Android.

3.5. Compatibilità comportamentale API
I comportamenti di ciascuno dei tipi di API (gestiti, software, nativi e Web) devono essere
coerente con l'implementazione preferita dell'open source Android a monte
progetto [Risorse, 3]. Alcune aree specifiche di compatibilità sono:
I dispositivi NON DEVONO modificare il comportamento o la semantica di un Intento standard
I dispositivi NON DEVONO alterare il ciclo di vita o la semantica del ciclo di vita di un particolare tipo
del componente di sistema (come Servizio, Attività, ContentProvider, ecc.)
I dispositivi NON DEVONO modificare la semantica di un permesso standard
L'elenco di cui sopra non è completo. I test di Compatibility Test Suite (CTS).
porzioni significative della piattaforma per la compatibilità comportamentale, ma non al . È il
responsabilità dell'implementatore per garantire la compatibilità comportamentale con Android
Progetto Open Source. Per questo motivo, gli implementatori del dispositivo DEVONO utilizzare la fonte
codice disponibile tramite l'Android Open Source Project, ove possibile, anziché
implementare parti significative del sistema.
3.6. Spazi dei nomi API
Android segue le convenzioni dello spazio dei nomi dei pacchetti e delle classi definite da Java

linguaggio di programmazione. Per garantire la compatibilità con applicazioni di terze parti, dispositivo
gli implementatori NON DEVONO apportare modifiche vietate (vedi sotto) a questi
spazi dei nomi del pacchetto:
Giava.*
javax.*
sole.*
Android.*
com.android.*
Le modifiche vietate includono:
Le implementazioni del dispositivo NON DEVONO modificare le API pubblicamente esposte sul
Piattaforma Android modificando qualsiasi metodo o firme di classe o rimuovendo
classi o campi di classe.
Gli implementatori del dispositivo POSSONO modificare l'implementazione sottostante delle API, ma
tali modifiche NON DEVONO influire sul comportamento dichiarato e sul linguaggio Java
firma di qualsiasi API esposta pubblicamente.
Gli implementatori del dispositivo NON DEVONO aggiungere alcun elemento pubblicamente esposto (come
classi o interfacce, o campi o metodi a classi o interfacce esistenti) al
API sopra.
Un "elemento pubblicamente esposto" è qualsiasi costrutto che non è decorato con "@hide"
marker utilizzato nel codice sorgente Android a monte. In altre parole, dispositivo
gli implementatori NON DEVONO esporre nuove API o alterare le API esistenti negli spazi dei nomi
notato sopra. Gli implementatori del dispositivo POSSONO apportare modifiche solo interne, ma quelle
le modifiche NON DEVONO essere pubblicizzate o altrimenti esposte agli sviluppatori.
Gli implementatori di dispositivi POSSONO aggiungere API personalizzate, ma tali API NON DEVONO essere in a
namespace di proprietà di o riferito a un'altra organizzazione. Ad esempio, dispositivo
gli implementatori NON DEVONO aggiungere API allo spazio dei nomi com.google.* o simile; solo
Google potrebbe farlo. Allo stesso modo, Google NON DEVE aggiungere API ad altre società
spazi dei nomi. Y aggiuntivo, se l'implementazione di un dispositivo include API personalizzate esterne
lo spazio dei nomi Android standard, quelle API DEVONO essere impacchettate in un Android
libreria condivisa in modo che solo le app che le utilizzino esplicitamente (tramite la <uses-library>
meccanismo) sono influenzati dal maggiore utilizzo della memoria di tali API.
Se un implementatore del dispositivo propone di migliorare uno degli spazi dei nomi del pacchetto sopra
(ad esempio aggiungendo nuove utili funzionalità a un'API esistente o aggiungendo una nuova API), il
l'implementatore DOVREBBE visitare source.android.com e iniziare il processo per contribuire
modifiche e codice, secondo le informazioni su quel sito.
Tieni presente che le restrizioni di cui sopra corrispondono alle convenzioni standard per la denominazione delle API in
il linguaggio di programmazione Java; questa sezione mira semplicemente a rafforzarli
convenzioni e renderle vincolanti mediante l'inclusione in questa definizione di compatibilità.
3.7. Compatibilità con macchine virtuali
Le implementazioni del dispositivo DEVONO supportare il bytecode completo Dalvik Executable (DEX).
specifica e semantica della macchina virtuale Dalvik [Risorse, 17].
Le implementazioni del dispositivo DEVONO configurare Dalvik per allocare la memoria in conformità
con la piattaforma Android a monte, e come specificato dalla tabella seguente. (Vedere
Sezione 7.1.1 per le dimensioni dello schermo e le definizioni della densità dello schermo.)
Si noti che i valori di memoria specificati di seguito sono considerati valori minimi e dispositivo
i implementazione s MAGGIO allocare più memoria per applicazione.
Dimensione dello schermo
Densità dello schermo
Memoria dell'applicazione
piccolo/normale/grande
ldpi/mdpi
16 MB
piccolo/normale/grande
tvdpi/hdpi
32 MB
piccolo/normale/grande
xhdpi
64 MB
xgrande
mdpi
32 MB
xgrande
tvdpi/hdpi
64 MB
xgrande
xhdpi
128 MB
3.8. Compatibilità interfaccia utente
3.8.1. Widget
Android definisce un tipo di componente e l'API e il ciclo di vita corrispondenti che consentono

applicazioni per esporre un "AppWidget" all'utente finale [Risorse , 18]. L' Androide
La versione di riferimento Open Source include un'applicazione di avvio che include l'utente
vantaggi dell'interfaccia che consentono all'utente di aggiungere, visualizzare e rimuovere AppWidgets dal file
schermo di casa.
Le implementazioni del dispositivo POSSONO sostituire un'alternativa al Launcher di riferimento (es
schermo di casa). I lanciatori alternativi DEVONO includere il supporto integrato per AppWidgets,
ed esporre i vantaggi dell'interfaccia utente da aggiungere, configurare, visualizzare e rimuovere
AppWidgets direttamente all'interno del Launcher. I lanciatori alternativi POSSONO omettere questi utenti
elementi di interfaccia; tuttavia, se vengono omessi, l'implementazione del dispositivo DEVE
fornire un'applicazione separata accessibile dal Launcher che consenta agli utenti di aggiungere,
configurare, visualizzare e rimuovere AppWidgets.
Le implementazioni del dispositivo DEVONO essere in grado di eseguire il rendering di widget che sono 4 x 4 nel file
dimensione della griglia standard. (Consulta le Linee guida per la progettazione dei widget delle app nell'SDK di Android
documentazione [Risorse, 18] per i dettagli.
3.8.2. Notifiche
Android include API che consentono agli sviluppatori di notificare agli utenti eventi importanti
[Risorse, 19], utilizzando le funzionalità hardware e software del dispositivo.
Alcune API consentono alle applicazioni di eseguire notifiche o attirare l'attenzione utilizzando
hardware, in particolare suono, vibrazione e luce. Le implementazioni del dispositivo DEVONO
notifiche di supporto che utilizzano funzionalità hardware, come descritto nell'SDK
documentazione e, per quanto possibile, con l'hardware di implementazione del dispositivo.
Ad esempio, se l'implementazione di un dispositivo include un vibratore, DEVE essere correttamente
implementare le API di vibrazione. Se l'implementazione di un dispositivo manca di hardware, il
corresponding APIs MUST be implemented as no-ops. Note that this behavior is
further detailed in Section 7.
Additional y, the im plementatio n MUST correctly render al resources (icons, sound
files, etc.) provided for in the APIs [Resources, 20], or in the Status/System Bar icon
style guide [Resources, 21]. Device implementers MAY provide an alternative user
experience for notifications than that provided by the reference Android Open Source
implementati on; however, suc h alternative notification systems MUST support existing
notification resources, as above.
Android 4.1 includes support for rich notifications, such as interactive Views for
ongoing notifications. Device implementations MUST properly display and execute rich
notifications, as documented in the Android APIs.
3.8.3. Search
Android includes APIs [Resources, 22] that al ow developers to incorporate search into
their applications, and expose their application's data into the global system search.
General y speaking, this f unctionality cons ists of a single, system-wide user interface
that al ows users to enter queries, displays suggestions as users type, and displays
results. The Android APIs al ow developers to reuse this interface to provide search
within their own apps, and al ow 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 al ow developers to reuse this user
interface to provide search within their own applications. Device implementations
MUST implement the APIs that al ow third-party applications to add suggestions to the
search box when it is run in global search mode. If no third-party applications are
instal ed that make use of this functionality, the default behavior SHOULD be to display
web search engine results and suggestions.
3.8.4. Toasts
Applications can use the "Toast" API (defined in [Resources, 23]) 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. Themes
Android provides "themes" as a mechanism for applications to apply styles across an
entire Activity or application. Android 3.0 introduced a new "Holo" or "holographic"
theme as a set of defined styles for application developers to use if they want to match
the Holo theme look and feel as defined by the Android SDK [Resources, 24]. Device
implementations MUST NOT alter any of the Holo theme attributes exposed to

applications [ Resources, 25].
Android 4.0 introduced a new "Device Default" theme as a set of defined styles for
application developers to use if they want to match the look and feel of the device
theme as defined by the device implementer. Device implementations MAY modify the
DeviceDefault theme attributes exposed to applications [Re sources, 25].
3.8.6. Live Wallpapers
Android defines a component type and corresponding API and lifecycle that al ows
applications to expose one or more "Live Wal papers" to the end user [Resources, 26].
Live Wal papers are animations, patterns, or similar images with limited input
capabilities that display as a wal paper, behind other applications.
Hardware is considered capable of reliably running live wal papers if it can run al live
wal papers, with no limitations on functionality, at a reasonable framerate with no
adverse affects on other applications. If limitations in the hardware cause wal papers
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 wal paper. As an example, some live wal papers may use an Open GL 1.0 or 2.0
context to render their content. Live wal paper wil not run reliably on hardware that
does not support multiple OpenGL contexts because the live wal paper use of an
OpenGL context may conflict with other applications that also use an OpenGL context.
Device implementations capable of running live wal papers reliably as described
above SHOULD implement live wal papers. Device implementations determined to not
run live wal papers reliably as described above MUST NOT implement live wal papers.
3.8.7. Recent Application Display
The upstream Android 4.1 source code includes a user interface for displaying recent
applications using a thumbnail image of the application's graphical state at the
moment the user last left the application. Device implementations MAY alter or
eliminate this user interface; however, a future version of Android is planned to make
more extensive use of this functionality. Device implementations are strongly
encouraged to use the upstream Android 4.1 user interface (or a similar thumbnail-
based interface) for recent applications, or else they may not be compatible with a
future version of Android.
3.8.8. Input Management Settings
Android 4.1 includes support for Input Management Engines. The Android 4.1 APIs
al ow custom app IMEs to specify user-tunable settings. Device implementations
MUST include a way for the user to access IME settings at al times when an IME that
provides such user settings is displayed.
3.8.9. Lock Screen Remote Control
Android 4.0 introduced support for Remote Control API that lets media applications
integrate with playback controls that are displayed in a remote view like the device
lock screen [Resources, 69]. Device implementations SHOULD include support for
embedding remote controls in the device lock screen.
3.9 Device Administration
Android 4.1 includes features that al ow security-aware applications to perform device
administration functions at the system level, such as enforcing password policies or
performing remote wipe, through the Android Device Administration API [Resources,
27]. Device implementations MUST provide an implementation of the
DevicePolicyManager class [Resources, 28], and SHOULD support the ful range of
device administration policies defined in the Android SDK documentation [Resources,
27].

Note: while some of the requirements outlined above are stated as "SHOULD" for
Android 4.1, the Compatibility Definition for a future version is planned to change these
to "MUST". That is, these requirements are optional in Android 4.1 but will be
required
by a future version. Existing and new devices that run Android 4.1 are very
strongly encouraged to meet these requirements in Android 4.1
, or they wil not
be able to attain Android compatibility when upgraded to the future version.
3.10 Accessibility
Android 4.1 provides an accessibility layer that helps users with disabilities to navigate
their devices more easily. In addition, Android 4.1 provides platform APIs that enable

accessibility service implementations to receive cal backs for user and system events
and generate alternate feedback mechanisms, such as text-to-speech, haptic
feedback, and trackbal /d-pad navigation [R esources, 29]. D evice implementations
MUST provide an implementation of the Android accessibility framework consistent
with the default Android implementation. Specifical y, device implementations MUST
meet the fol owing requirements.
Device implementations MUST support third party accessibility service
i mplementations through the android.accessibilityservice APIs [Resources,
30].
Device implementations MUST generate AccessibilityEvents and deliver
these events to al registered AccessibilityService implementations in a
manner consistent with the default Android implementation.
Device implementations MUST provide a user-accessible mechanism to enable
and disable accessibility services, and MUST display this interface in response
to the android.provider.Settings.ACTION_ACCESSIBILITY_SETTINGS intent.
Additional y, device implementations SHOULD provide an implementation of an
accessibility service on the device, and SHOULD provide a mechanism for users to
enable the accessibility service during device setup. An open source implementation
of an accessibility service is available from the Eyes Free project [Resources, 31].
3.11 Text-to-Speech
Android 4.1 includes APIs that al ow applications to make use of text-to-speech (TTS)
services, and al ows service providers to provide implementations of TTS services
[Resources, 32]. Device implementations MUST meet these requirements related to
t he Android TTS framework:
Device implementations MUST support the Android TTS framework APIs and
SHOULD include a TTS engine supporting the languages available on the
device. Note that the upstream Android open source software includes a ful -
featured TTS engine implementation.
Device implementations MUST support instal ation of third-party TTS engines.
Device implementations MUST provide a user-accessible interface that al ows
users to select a TTS engine for use at the system level.
4. Application Packaging Compatibility
Device implementations MUST instal and run Android ".apk" files as generated by the
"aapt" tool included in the official Android SDK [Resources, 33].
Devices implementations MUST NOT extend eithe r the .apk [Reso urces, 34], Android
Manifest [Resources, 35], Dalvik bytecode [Resources, 17], or renderscript bytecode
formats in such a way that would prevent those files from instal in g and running co rrectly
on other c ompatible device s. Device impleme nters SHOULD u se the reference
upstream implementation of Dalvik, and the reference implementation's package
management system.
5. Multimedia Compatibility
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 core media formats specified in the
Android SDK documentation [Resources, 58] except where explicitly permitted in this
document. Specifical y, device implementations MUST support the media formats,
encoders, decoders, file types and container formats defined in the tables below. Al of
these codecs are provided as s oftware impleme ntations 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.

Note that these tables do not list specific bitrate requirements for most video codecs
because 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.

File Type(s) /
Format /
Type
Encoder
Decoder
Details
Container
Codec
Formats
Support for
REQUIRED
mono/stereo/5.0/5.1*
MPEG-4
Required for device implementations
content with
AAC Profile
that include microphone hardware
REQUIRED
standard sampling
(AAC LC)
and define
3GPP
rates from 8 to 48
android.hardware.microphone.
(.3gp)
kHz.
MPEG-4
Support for
(.mp4,
MPEG-4
mono/stereo/5.0/5.1*
.m4a)
HE AAC
content with
ADTS raw

REQUIRED
Profile
standard sampling
AAC (.aac,
(AAC+)
rates from 16 to 48
decode in
kHz.
Androide
3.1+,
Support for
MPEG-4
REQUIRED for device
encode in
mono/stereo/5.0/5.1*
HE AAC v2
implementations that include
Androide
content with
Profile
microphone hardware and

4.0+, ADIF
standard sampling
(enhanced
define
not
rates from 16 to 48
AAC+)
android.hardware.microphone
supported)
kHz.
MPEG-TS
MPEG-4
(.ts, not
Audio
REQUIRED for device
Support for
seekable,
Object Type
implementations that include
mono/stereo content
Androide
ER AAC
microphone hardware and
REQUIRED
with standard
3.0+)
ELD
define
sampling rates from
(Enhanced
android.hardware.microphone
16 to 48 kHz.
Low Delay
AAC)
REQUIRED
Required for device implementations
4.75 to 12.2 kbps
AMR-NB
that include microphone hardware
REQUIRED
3GPP (.3gp)
sampled @ 8kHz
and define
android.hardware.microphone.
REQUIRED
Required for device implementations
9 rates from 6.60
AMR-WB
that include microphone hardware
REQUIRED
kbit/s to 23.85 kbit/s
3GPP (.3gp)
and define
sampled @ 16kHz
android.hardware.microphone.
Mono/Stereo (no
multichannel).
Audio
Sample rates up to
48 kHz (but up to
44.1 kHz is
recommended on
devices with 44.1
REQUIRED
FLAC

kHz output, as the 48
FLAC (.flac) only
(Android 3.1+)
to 44.1 kHz
downsampler does
not include a low-
pass filter). 16-bit
recommended; no
dither applied for 24-
bit.
Mono/Stereo 8-
320Kbps constant
MP3

REQUIRED
MP3 (.mp3)
(CBR) or variable
bit-rate (VBR)
Type 0 and
MIDI Type 0 and 1.
1 (.mid,
DLS Version 1 and
.xmf, .mxmf)
2. XMF and Mobile
RTTTL/RTX
MIDI

REQUIRED
XMF. Support for
(.rtttl, .rtx)
ringtone formats
OTA (.ota)
RTTTL/RTX, OTA,
iMelody
and iMelody
(.imy)

Ogg (.ogg)
Vorbis

REQUIRED

Matroska
(.mkv)
8-bit and 16-bit
linear PCM** (rates
up to limit of
hardware).Devices
MUST support
PCM/WAVE
REQUIRED
REQUIRED
WAVE (.wav)
sampling rates for
raw PCM recording
at 8000,16000 and
44100 Hz
frequencies
JPEG
REQUIRED
REQUIRED
Base+progressive
JPEG (.jpg)
GIF

REQUIRED

GIF (.gif)
Image
PNG
REQUIRED
REQUIRED

PNG (.png)
BMP

REQUIRED

BMP (.bmp)
WEBP
REQUIRED
REQUIRED

WebP (.webp)
REQUIRED
Required for device implementations
3GPP
that include camera hardware and
(.3gp)
H.263
REQUIRED

define android.hardware.camera
MPEG-4
or
(.mp4)
android.hardware.camera.front.
3GPP
(.3gp)
REQUIRED
MPEG-4
(.mp4)
Required for device implementations
MPEG-TS
that include camera hardware and
Baseline Profile
Video
H.264 AVC
REQUIRED
(.ts, AAC
define android.hardware.camera
(BP)
audio only,
or
not
android.hardware.camera.front.
seekable,
Androide
3.0+)
MPEG-4

REQUIRED

3GPP (.3gp)
SP
WebM (.webm)
REQUIRED
and Matroska
VP8

(Android

(.mkv, Android
2.3.3+)
4.0+)
*Note: Only downmix of 5.0/5.1 content is required; recording or rendering more than 2
channels is optional. **Note: 16-bit linear PCM capture is mandatory. 8-bit linear PCM
capture is not mandatory.
5.2 Video Encoding
Android device implementations that include a rear-facing camera and declare
android.hardware.camera SHOULD support the fol owing video encoding profiles.
HD (When supported by
 
SD (Low quality) SD (High quality)
hardware)
H.264 Baseline
H.264 Baseline
Video codec
H.264 Baseline Profile
Profile
Profile
Video
176 x 144 px
480 x 360 px
1280 x 720 px
resolution
Video frame 12 fps
30 fps
30 fps
rate
500 Kbps or
Video bitrate 56 Kbps
2 Mbps or higher
higher
Audio codec AAC-LC
AAC-LC
AAC-LC

Audio
1 (mono)
2 (stereo)
2 (stereo)
channels
Audio bitrate 24 Kbps
128 Kbps
192 Kbps
5.3. Audio Recording
When an application has used the android.media.AudioRecord API to start recording
an audio stream, device implementations that include microphone hardware and
declare android.hardware.microphone MUST sample and record audio with each of
these behaviors:
The device SHOULD exhibit approximately flat amplitude versus frequency
characteristics; specifical y, ±3 dB, from 100 Hz to 4000 Hz
Audio input sensitivity SHOULD be set such that a 90 dB sound power level
(SPL) source at 1000 Hz yields RMS of 2500 for 16-bit samples.
PCM amplitude levels SHOULD linearly track input SPL changes over at least a
30 dB range from -18 dB to +12 dB re 90 dB SPL at the microphone.
Total harmonic distortion SHOULD be less than 1% for 1Khz at 90 dB SPL input
level.
In addition to the above recording specifications, when an application has started
recording an audio stream using the
android.media.MediaRecorder.AudioSource.VOICE_RECOGNITION audio source:
Noise reduction processing, if present, MUST be disabled.
Automatic gain control, if present, MUST be disabled.
Note: while some of the requirements outlined above are stated as "SHOULD" for
Android 4.1, the Compatibility Definition for a future version is planned to change these
to "MUST". That is, these requirements are optional in Android 4.1 but will be
required
by a future version. Existing and new devices that run Android 4.1 are very
strongly encouraged to meet these requirements in Android 4.1
, or they wil not
be able to attain Android compatibility when upgraded to the future version.
5.4. 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 actual y
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 al 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 physical y 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 cal back, 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 cal back, while the device is in recording mode
Using the above definitions, device implementations SHOULD exhibit each of these
properties:
cold output latency of 100 mil iseconds or less
warm output latency of 10 mil iseconds or less
continuous output latency of 45 mil iseconds or less
cold input latency of 100 mil iseconds or less
continuous input latency of 50 mil iseconds or less
Note: while the requirements outlined above are stated as "SHOULD" for Android 4.1,

the Compatibility Definition for a future version is planned to change these to "MUST".
That is, these requirements are optional in Android 4.1 but will be required by a future
version. Existing and new devices that run Android 4.1 are very strongly
encouraged to meet these requirements in Android 4.1
, or they wil 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. [Re sources, 37]
Conversely, if the device implementation does not meet these requirements it MUST
NOT report support for low-latency audio.
5.5. Network Protocols
Devices MUST support the media network protocols for audio and video playback as
specified in the Android SDK documentation [Resources, 58]. Specifical y, devices
MUST support the fol owing media network proto cols:
RTSP (RTP, SDP)
HTTP(S) progressive streaming
HTTP(S) Live Streaming draft protocol, Version 3 [Resources, 59]
6. Developer Tool Compatibility
Device implementations MUST support the Android Developer Tools provided in the
Android SDK. Specifical y, Android-compatible devices MUST be compatible with:
Android Debug Bridge (known as adb) [Resources, 33]
Device implementations MUST support al adb functions as doc umented in the
Android SDK. The device-side adb daemon MUST be inactive by default, and
there MUST be a user-accessible mechanism to turn on the Android Debug
Bridge.
Dalvik Debug Monitor Service (known as ddms) [Resources, 33]
Device implementations MUST support al 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, 36]
Device implementations MUST include the Monkey framework, and make it
available f or 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 typical y 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 al owing 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
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 stil be present
the API's behaviors MUST be implemented as no-ops in some reasonable
fashion
API methods MUST return nul values where permitted by the SDK
documentation
API methods MUST return no-op implementations of classes where nul 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. [Re sources, 37]
7.1. Display and Graphics
Android 4.1 includes facilities that automatical y adjust application assets and UI
layouts appropriately for the device, to ensure that third-party applications run wel on a
variety of hardware configurations [Resources, 38]. Devices MUST properly implement
these APIs and behaviors, as detailed in this section.
The units referenced by the requirements in this section are defined as fol ows:
"Physical diagonal size" is the distance in inches between two opposing corners
of the il uminated 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 fal 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".
A "density-independent pixel" or ("dp") is the virtual pixel unit normalized to a 160
dpi screen, calculated as: pixels = dps * (density / 160).
7.1.1. Screen Configuration
Screen Size
The Android UI framework supports a variety of different screen sizes, and al ows
applications to query the device screen size (aka "screen layout") via
android.content.res.Configuration.screenLayout with the
SCREENLAYOUT_SIZE_MASK. Device implementations MUST report the correct screen
size as defined in the Android SDK documentation [Resources, 38] and determined by
the upstream Android platform. Specifical y, device implementations must report the
correct screen size according to the fol owing logical d ensity-independe nt pixel (dp)
screen dimensions.
Devices MUST have screen sizes of at least 426 dp x 320 dp ('smal ')
Devices that report screen size 'normal' MUST have screen sizes of at least 480
dp x 320 dp
Devices that report screen size 'large' MUST have screen sizes of at least 640
dp x 480 dp
Devices that report screen size 'xlarge' MUST have screen sizes of at least 960
dp x 720 dp
In addition, devices MUST have screen sizes of at least 2.5 inches in physical diagonal
size.
Devices MUST NOT change their reported screen size at any time.
Applications optional y 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 smal , normal, large, and xlarge
screens, as described in the Android SDK documentation.
Screen Aspect Ratio
The aspect ratio MUST be between 1.3333 (4:3) and 1.85 (16:9).
Screen Density
The Android UI framework defines a set of standard logical densities to help
application developers target application resources. Device implementations MUST
report one of the fol owing logical Android framework densities through the
android.util.DisplayMetrics APIs, and MUST execute applications at this standard
density.
120 dpi, known as 'ldpi'
160 dpi, known as 'mdpi'
213 dpi, known as 'tvdpi'
240 dpi, known as 'hdpi'
320 dpi, known as 'xhdpi'
480 dpi, known as 'xxhdpi'
Device implementations SHOULD define the standard Android framework density that
is numerical y closest to the physical density of the screen, unless that logical density

is numerical y closest to the physical density of the screen, unless that logical density
pushes the reported screen size below the minimum supported. If the standard Android
framework density that is numerical y closest to the physical density results in a screen
size that is smal er than the smal est supported compatible screen size (320 dp width),
device implementations SHOULD report the next lowest standard Android framework
density.
7.1.2. Display Metrics
Device implementations MUST report correct values for al display metrics defined in
android.util.DisplayMetrics [Resources, 39].
7.1.3. Screen Orientation
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 MUST report the correct value for the device's current orientation, whenever
queried via the android.content.res.Configuration.orientation,
android.view.Display.getOrientation(), or other APIs.
Devices MUST NOT change the reported screen size or density when changing
orientation.
Devices MUST report which screen orientations they support (
android.hardware.screen.portrait and/or android.hardware.screen.landscape)
and MUST report at least one supported orientation. For example, a device with a
fixed-orientation landscape screen, such as a television or laptop, MUST only report
android.hardware.screen.landscape.
7.1.4. 2D and 3D Graphics Acceleration
Device implementations MUST support both OpenGL ES 1.0 and 2.0, as embodied
and detailed in the Android SDK documentations. Device implementations MUST also
support Android Renderscript, as detailed in the Android SDK documentation
[Resources, 8].
Device impleme ntations MUST also correctly identify themselves as supporting
OpenGL ES 1.0 and 2.0. That is:
The managed APIs (such as via the GLES10.getString() method) MUST report
support for OpenGL ES 1.0 and 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 report support for
OpenGL ES 1.0 and 2.0.
Device implementations MAY implement any desired OpenGL ES extensions.
However, device implementations MUST report via the OpenGL ES managed and
native APIs al extension strings that they do support, and conversely MUST NOT report
extension strings that they do not support.
Note that Android 4.1 includes support for applications to optional y specify that they
require specific OpenGL texture compression formats. These formats are typical y
vendor-specific. Device implementations are not required by Android 4.1 to implement
any specific texture compression format. However, they SHOULD accurately report any
texture compression formats that they do support, via the getString() method in the
OpenGL API.
Android 4.1 includes a mechanism for applications to declare that they wanted to
enable hardware acceleration for 2D graphics at the Application, Activity, Window or
View level through the use of a manifest tag android:hardwareAccelerated or direct
API cal s [Resources, 9].
In Android 4.1, device implementations MUST enable hardware acceleration by
default, and MUST disable hardware acceleration if the developer so requests by
setting android:hardwareAccelerated="false" or disabling hardware acceleration
directly through the Android View APIs.
In addition, device implementations MUST exhibit behavior consistent with the Android
SDK documentation on hardware acceleration [Resources, 9].
Android 4.1 includes a TextureView object that lets developers directly integrate
hardware-accelerated OpenGL ES textures as rendering targets in a UI hierarchy.
Device implementations MUST support the Textur eView API, and MUST exhibit

consistent behavior with the upstream Android implementation.
7.1.5. Legacy Application Compatibility Mode
Android 4.1 specifies a "compatibility mode" in which the framework operates in an
'normal' screen size equivalent (320dp width) mode for the benefit of legacy
applications not developed for old versions of Android that pre-date screen-size
independence. Device implementations MUST include support for legacy application
compatibility mode as implemented by the upstream Android open source code. That
is, device implementations MUST NOT alter the triggers or thresholds at which
compatibility mode is activated, and MUST NOT alter the behavior of the compatibility
mode itself.
7.1.6. Screen Types
Device implementation screens are classified as one of two types:
Fixed-pixel display implementations: the screen is a single panel that supports
only a single pixel width and height. Typical y the screen is physical y integrated
with the device. Examples include mobile phones, tablets, and so on.
Variable-pixel display implementations: the device implementation either has no
embedded screen and includes a video output port such as VGA, HDMI or a
wireless port for display, or has an embedded screen that can change pixel
dimensions. Examples include televisions, set-top boxes, and so on.
Fixed-Pixel Device Implementations
Fixed-pixel device implementations MAY use screens of any pixel dimensions,
provided that they meet the requirements defined this Compatibility Definition.
Fixed-pixel implementations MAY include a video output port for use with an external
display. However, if that display is ever used for running apps, the device MUST meet
the fol owing requirements:
The device MUST report the same screen configuration and display metrics, as
detailed in Sections 7.1.1 and 7.1.2, as the fixed-pixel display.
The device MUST report the same logical density as the fixed-pixel display.
The device MUST report screen dimensions that are the same as, or very close
to, the fixed-pixel display.
For example, a tablet that is 7" diagonal size with a 1024x600 pixel resolution is
considered a fixed-pixel large mdpi display implementation. If it contains a video
output port that displays at 720p or 1080p, the device implementation MUST scale the
output so that applications are only executed in a large mdpi window, regardless of
whether the fixed-pixel display or video output port is in use.
Variable-Pixel Device Implementations
Variable-pixel device implementations MUST support one or both of 1280x720, or
1920x1080 (that is, 720p or 1080p). Device implementations with variable-pixel
displays MUST NOT support any other screen configuration or mode. Device
implementations with variable-pixel screens MAY change screen configuration or
mode at runtime or boot-time. For example, a user of a set-top box may replace a
720p display with a 1080p display, and the device implementation may adjust
accordingly.
Additional y, variable-pixel device implementations MUST report the fol owing
configuration buckets for these pixel dimensions:
1280x720 (also known as 720p): 'large' screen size, 'tvdpi' (213 dpi) density
1920x1080 (also known as 1080p): 'large' screen size, 'xhdpi' (320 dpi) density
For clarity, device implementations with variable pixel dimensions are restricted to
720p or 1080p in Android 4.1, and MUST be configured to report screen size and
density buckets as noted above.
7.1.7. Screen Technology
The Android platform includes APIs that al ow applications to render rich graphics to
the display. Devices MUST support al of these APIs as defined by the Android SDK
unless specifical y al owed in this document. Specifical y:
Devices MUST support displays capable of rendering 16-bit color graphics and
SHOULD support displays capable of 24-bit color graphics.
Devices MUST support displays capable of rendering animations.
The display technology used MUST have a pixel aspect ratio (PAR) between 0.9

and 1.1. That is, the pixel aspect ratio MUST be near square (1.0) with a 10%
tolerance.
7.2. Input Devices
7.2.1. Keyboard
Device implementations:
MUST include support for the Input Management Framework (which al ows third
party developers to create Input Management Engines - ie soft keyboard) as
detailed at http://developer.android.com
MUST provide at least one soft keyboard implementation (regardless of whether
a hard keyboard is present)
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, 40]
(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 trackbal , d-pad, or
wheel)
MUST report the correct value for
android.content.res.Configuration.navigation [Resources, 40]
MUST provide a reasonable alternative user interface m echanism for the
selection and editing of text, compatible with Input Management Engines. The
upstream Android open source software 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 al times when running applications. These functions MAY be implemented via
dedicated physical buttons (such as mechanical or capacitive touch buttons), or MAY
be implemented using dedicated software keys, gestures, touch panel, etc. Android
4.1 supports both implementations.
Android 4.1 introduces support for assist action [Resources, 63]. Device
implementations MUST make the assist action available to the user at al times when
running applications. This function MAY be impleme nted via hardwa re or software
keys.
Device implementations MAY use a distinct portion of the screen to display the
navigation keys, but if so, MUST meet these requirements:
Device implementation navigation keys MUST use a distinct portion of the
screen, not available to applications, and MUST NOT obscure or otherwise
interfere with the portion of the screen available to applications.
Device implementations MUST make available a portion of the display to
applications that meets the requirements defined in Section 7.1.1.
Device implementations MUST display the navigation keys when applications do
not specify a system UI mode, or specify SYSTEM_UI_FLAG_VISIBLE.
Device implementations MUST present the navigation keys in an unob trusive
"low profile" (eg. dimmed) mode when applications specify
SYSTEM_UI_FLAG_LOW_PROFILE.
Device implementations MUST hide the navigation keys when applications
specify SYSTEM_UI_FLAG_HIDE_NAVIGATION.
Device implementation MUST present a Menu key to applications when
targetSdkVersion <= 10 and SHOULD NOT present a Menu key when the
targetSdkVersion > 10.
Device implementations MUST make available a portion of the display to
applications that meets the requirements defined in Section 7.1.1.
7.2.4. Touchscreen input
Device implementations SHOULD have a pointer input syste m of some kind (either
mouse-like, or touch). However, if a device implementation does not support a pointer
input system, it MUST NOT report the android.hardware.touchscreen or
android.hardware.faketouch feature constant. Device implementations that do

include a pointer input system:
SHOULD support ful y independently tracked pointers, if the device input system
supports multiple pointers
MUST report the value of android.content.res.Configuration.touchscreen
[ Resources, 40] c orresponding to the type of the specific touchscreen on the
device
Android 4.0 includes support for a variety of touch screens, touch pads, and fake touch
input devices. Touch screen based device implementations are associated with a
display [Resources, 71] such that the user has the impression of directly manipulating
items on screen. Since the user is directly touching the screen, the system does not
require any additional affordances to indicate the objects being manipulated. In
contrast, a fake touch interface provides a user input system that approximates a
subset of touchscreen capabilities. For example, a mouse or remote control that drives
an on-screen cursor approximates touch, but requires the user to first point or focus
then click. Numerous input devices like the mouse, trackpad, gyro-based air mouse,
gyro-pointer, joystick, and multi-touch trackpad can support fake touch interactions.
Android 4.0 includes the feature constant android.hardware.faketouch, which
corresponds to a high-fidelity non-touch (that is, pointer-based) input device such as a
mouse or trackpad that can adequately emulate touch-based input (including basic
gesture support), and indicates that the device supports an emulated subset of
touchscreen functionality. Device implementations that declare the fake touch feature
MUST meet the fake touch requirements in Section 7.2.5.
Device implementations MUST report the correct feature corresponding to the type of
input used. Device implementations that include a touchscreen (single-touch or better)
MUST report the platform feature constant android.hardware.touchscreen. Device
implementations that report the platform feature constant
android.hardware.touchscreen MUST also report the platform feature constant
android.hardware.faketouch. Device implementations that do not include a
touchscreen (and rely on a pointer device only) MUST NOT report any touchscreen
feature, and MUST report only android.hardware.faketouch if they meet the fake
touch requirements in Section 7.2.5.
7.2.5. Fake touch inp ut
Device implementations that declare support for android.hardware.faketouch
MUST report the absolute X and Y screen positions of the pointer location and
display a visual pointer on the screen[Resources, 70]
MUST report touch event with the action code [Resources, 70] that specifies the
state change that occurs on the pointer g oing down or up on the screen
[Resources, 70]
MUST support pointer down and up on an object on the screen, which al ows
u sers to emulate tap on an object on the screen
MUST support pointer down, pointer up, pointer down then pointer up in the same
place on an object on the screen within a time threshold, which al ows users to
emulate double tap on an object on the screen [Resources, 70]
MUST support pointer down on an arbitrary point on the screen, pointer move to
any other arbitrary point on the screen, fol owed by a pointer up , which al ows
users to emulate a touch drag
MUST support pointer down then al ow users to quickly move the object to a
different position on the screen and then pointer up on the screen, which al ows
users to fling an object on the screen
Devices that declare support for android.hardware.faketouch.multitouch.distinct
MUST meet the requirements for faketouch above, and MUST also support distinct
tracking of two or more independent pointer inputs.
7.2.6. Microphone
Device implementations MAY omit a microphone. However, if a device implementation
omits a microphone, it MUST NOT report the android.hardware.microphone feature
constant, and must implement the audio recording API as no-ops, per Section 7.
Conversely, device implementations that do possess a microphone:
MUST report the android.hardware.microphone feature constant
SHOULD meet the audio quality requirements in Section 5.4
SHOULD meet the audio latency requirements in Section 5.5
7.3. Sensors

Android 4.1 includes APIs for accessing a variety of sensor types. Devices
implementations general y MAY omit these sensors, as provided for in the fol owing
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. [Re sources, 37]
MUST return an accurate list of supported sensors via the
SensorManager.getSensorList() and similar methods
MUST behave reasonably for al other sensor APIs (for example, by returning true
or false as appropriate when applications attempt to register listeners, not cal ing
sensor listeners when the corresponding sensors are not present; etc.)
MUST report al sensor measurements using the relevant International System of
Units (ie metric) values for each sensor type as defined in the Android SDK
documentation [Resources, 41]
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 4.1 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 4.1 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:
SHOULD be able to deliver events at 120 Hz or greater. Note that while the
accelerometer frequency above is stated as "SHOULD" for Android 4.1, the
Compatibility Definition for a future version is planned to change these to
"MUST". That is, these standards are optional in Android 4.1 but will be
required
in future versions. Existing and new devices that run Android 4.1 are
very strongly encouraged to meet these requirements in Android 4.1 so
they wil be able to upgrade to the future platform releases
MUST comply with the Android sensor coordinate system as detailed in the
Android APIs (see [Resources, 41])
MUST be capable of measuring from freefal up to twice gravity (2g) or more on
any three-dimension al 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, 41]).
MUST be capable of sampling a range of field strengths adequate to cover the
geomagnetic field
MUST have 8-bits of accuracy or mor e
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 temperature compensated
MUST be capable of measuring orientation changes up to 5.5*Pi
radians/second (that is, approximately 1,000 degrees per second)
SHOULD be able to deliver events at 200 Hz or greater. Note that while the
gyroscope frequency above is stated as "SHOULD" for Android 4.1, the
Compatibility Definition for a future version is planned to change these to
"MUST". That is, these standards are optional in Android 4.1 but will be
required
in future versions. Existing and new devices that run Android 4.1 are
very strongly encouraged to meet these requirements in Android 4.1 so
they wil be able to upgrade to the future platform releases
MUST have 12-bits of accuracy or more
MUST have a variance no greater than 1e-7 rad^2 / s^2 per Hz (variance per Hz,
or rad^2 / s). The variance is al owed to vary with the sampling rate, but must be
constrained by this value. In other words, if you measure the variance of the gyro
at 1 Hz sampling rate it should be no greater than 1e-7 rad^2/s^2.
MUST have timestamps as close to when the hardware event happened as
possible. The constant latency must be removed.
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
MUST be temperature compensated
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 4.1 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
7.4.1. Telephony
"Telephony" as used by the Android 4.1 APIs and this document refers specifical y to
hardware related to placing voice cal s and sending SMS messages via a GSM or
CDMA network. While these voice cal s may or may not be packet-switched, they are
for the purposes of Android 4.1 considered independent of any data connectivity that
may be implemented using the same network. In other words, the Android "telephony"
functionality and APIs refer specifical y to voice cal s and SMS; for instance, device
implementations that cannot place cal s or send/receive SMS messages MUST NOT
report the "android.hardware.telephony" feature or any sub-features, regardless of
whether they use a cel ular network for data connectivity.
Android 4.1 MAY be used on devices that do not include telephony hardware. That is,
Android 4.1 is compatible with devices that are not phones. However, if a device
implementation does include GSM or CDMA telephony, it MUST implement ful support
for the API for that technology. Device implementations that do not include telephony
hardware MUST implement the ful APIs as no-ops.
7.4.2. IEEE 802.11 (WiFi)
Android 4.1 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.

Device implementations MUST implement the multicast API as described in the SDK
documentation [ Resources, 62]. D evice implementations that do include Wifi support
MUST support multicast DNS (mDNS). Device implementations MUST not filter mDNS
packets (224.0.0.251) at any time of operation including when the screen is not in an
active state.
7.4.2.1. WiFi Direct
Device implementations SHOULD include support for Wifi direct (Wifi peer-to-peer). If
a device implementation does include support for Wifi direct, it MUST implement the
corresponding Android API as described in the SDK documentation [Resources, 68]. If
a device implementation includes support for Wifi direct, then it:
MUST support regular Wifi operation
SHOULD support concurrent wifi and wifi Direct operation
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, 42]. 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 ful y 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, 37]
MUST be capable of reading and writing NDEF messages via the fol owing NFC
s tandards:
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 fol owing NFC standards:
NfcA (ISO14443-3A)
NfcB (ISO14443-3B)
NfcF (JIS 6319-4)
IsoDep (ISO 14443-4)
NFC Forum Tag Types 1, 2, 3, 4 (defined by the NFC Forum)
SHOULD be capable of reading and writing NDEF messages via the fol owing
NFC standards. Note that while the NFC standards below are stated as
"SHOULD" for Android 4.1, the Compatibility Definition for a future version is
planned to change these to "MUST". That is, these standards are optional in
Android 4.1 but will be required in future versions. Existing and new devices
that run Android 4.1 are very strongly encouraged to meet these
requirements in Android 4.1
so they wil be able to upgrade to the future
platform releases.
NfcV (ISO 15693)
MUST be capable of transmitting and receiving data via the fol owing 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, 43]
SNEP 1.0 (defined by the NFC Forum)
MUST include support for Android Beam [Resources, 65]:
MUST implement the S NEP default serv er. Valid NDEF messages
received by the default SNEP server MUST be dispatched to applications
using the android.nfc.ACTION_NDEF_DISCOVERED intent. Disabling
Android Beam in settings MUST NOT disable dispatch of incoming NDEF
message.
Device implementations MUST honor the
android.settings.NFCSHARING_SETTINGS intent to show NFC sharing

settings [R esources, 67].
MUST implement the NPP server. Messages received by the NPP server
MUST be processed the same way as the SNEP default server.
MUST implement a SNEP client and attempt to send outbound P2P NDEF
to the default SNEP server when Android Beam is enabled. If no default
SNEP server is found then the client MUST attempt to send to an NPP
server.
MUST al ow foreground activities to set the outbound P2P NDEF message
using android.nfc.NfcAdapter.setNdefPushMessage, and
android.nfc.NfcAdapter.setNdefPushMessageCal back, and
android.nfc.NfcAdapter.enableForegroundNdefPush.
SHOULD use a gesture or on-screen confirmation, such as 'Touch to
Beam', before sending outbound P2P NDEF messages.
SHOULD enable Android Beam by default
MUST support NFC Connection handover to Bluetooth when the device
supports Bluetooth Object Push Profile. Device implementations must
support connection handover to Bluetooth when using
android.nfc.NfcAdapter.setBeamPushUris, by implementing the
"Connection Handover version 1.2" [Resources, 60] and "Bluetooth Secure
Simple Pairing Using NFC version 1.0" [Resources, 61 ] specs from the
NFC Forum. Such an implementation SHO ULD use SNEP G ET requests
for exchanging the handover request / select records over NFC, and it
MUST use the Bluetooth Object Push Profile for the actual Bluetooth data
transfer.
MUST pol for al supported technologies while in NFC discovery mode.
SHOULD be in NFC discovery mode while the device is awake with the screen
active and the lock-screen unlocked.
(Note that publicly available links are not available for the JIS, ISO, and NFC Forum
specifications cited above.)
Additional y, device implementations MAY include reader/writer support for the
fol owing MIFARE technologies.
MIFARE Classic (NXP MF1S503x [Resources, 44], MF1S703x [Resources, 44])
MIFARE Ultralight (NXP MF0ICU1 [Resources, 46], MF0ICU2 [Resources, 46])
NDEF on MIFARE Classic (NXP AN1 30511 [Resourc es, 48], AN13 0411
[Resources, 49])
Note th at Android 4.1 in cludes APIs for these MIFARE types. If a device
implementation supports MIFARE in the reader/writer role, it:
MUST implement the corresponding Android APIs as documented by the
Android SDK
MUST report the feature com.nxp.mifare from the
android.content.pm.PackageManager.hasSystemFeature() method.
[Resources, 37] Note that this is not a standard Android feature, and as such
does not appear as a constant on the PackageManager class.
MUST NOT imple ment 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, 37],
and MUST implement the Android 4.1 NFC API as a no-op.
As the classes android.nfc.NdefMessage and android.nfc.NdefRecord r epresent 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. Specifical y, 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 typical y 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.PreviewCal back 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 4.1 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 horizontal y reflect (ie mirror) the stream displayed by an app in a
CameraPreview, as fol ows:
If the device implementation is capable of being rotated by user (such as
automatical y via an accelerometer or manual y via user input), the camera
preview MUST be mirrored horizontal y relative to the device's current
orientation.
If the current application has explicitly requested that the Camera display
be rotated via a cal to the
android.hardware.Camera.setDisplayOrientation() [Resources, 50]
method, the camera preview MUST be mirrored horizontal y relative to the
orientation specified by the application.
Otherwise, the preview MUST be mirrored along the device's default
horizontal axis.
MUST mirror the image displayed by the postview in the same manner as the
camera preview image stream. (If the device implementation does not support
postview, this requirement obviously does not apply.)
MUST NOT mirror the final captured stil image or video streams returned to
application cal backs or committed to media storage
7.5.3. Camera API Behavior
Device implementations MUST implement the fol owing behaviors for the camera-
related APIs, for both front- and rear-facing cameras:
1. If an application has never cal ed
android.hardware.Camera.Parameters.setPreviewFormat(int), then the
device MUST use android.hardware.PixelFormat.YCbCr_420_SP for preview
data provided to application cal backs.
2. If an application registers an android.hardware.Camera.PreviewCallback
instance and the system cal s 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 MUST support the YV12 format (as denoted by the

android.graphics.ImageFormat.YV12 constant) for camera previews for both
front- and rear-facing cameras. (The hardware video decoder and camera may
use any native pixel format, but the device implementation MUST support
conversion to YV12.)
Device implementations MUST implement the ful Camera API included in the Android
4.1 SDK documentation [R esources, 51]), r egardless of whether the device includes
hardware autofocus or other capabilities. For instance, cameras that lack autofocus
MUST stil cal 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 cal backs must stil 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 al standard Camera parameters if the hardware
al ows, and MUST NOT support custom Camera parameter types.
Device implementations MUST broadcast the Camera.ACTION_NEW_PICTURE intent
whenever a new picture is taken by the camera and the entry of the picture has been
added to the media store.
Device implementations MUST broadcast the Camera.ACTION_NEW_VIDEO intent
whenever a new video is recorded by the camera and the entry of the picture has been
added to the media store.
7.5.4. 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 dimention. That is, when the
device is held in the landscape orientation, cameras MUST capture images in the
landscape orientation. This applies regardless of the device's natural orientation; that
is, it applies to landscape-primary devices as wel as portrait-primary devices.
7.6. Memory and Storage
7.6.1. Minimum Memory and Storage
Device implementations MUST have at least 340MB of memory available to the kernel
and userspace. The 340MB MUST be in addition to any memory dedicated to
hardware components such as radio, video, and so on that is not under the kernel's
control.
Device implementations MUST have at least 350MB of non-volatile storage available
for application private data. That is, the /data partition MUST be at least 350MB.
The Android APIs include a Download Manager that applications may use to download
data files [Resources, 56]. The device implementation of the Download Manager
MUST be capable of downloading individual files of at least 100MB in size to the
default "cache" location.
7.6.2. Application Shared Storage
Device implementations MUST offer shared storage for applications. 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 al ocate
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 (UMS) or Media Transfer Protocol (MTP).
Device implementations MAY use USB mass storage, but SHOULD use Media
Transfer Protocol. If the device implementation supports Media Transfer Protocol:
The device implementation SHOULD be compatible with the reference Android
MTP host, Android File Transfer [R esources, 57].
The device implementation SHOULD report a USB device class of 0x00.
The device implementation SHOULD report a USB interface name of 'MTP'.
If the device implementation lacks USB ports, it MUST provide a host computer with
access to the contents of shared storage by some other means, such as a network file
system.
It is il ustrative 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 SHOULD include a USB client port, and SHOULD include a
USB host port.
If a device implementation includes a USB client port:
the port MUST be connectable to a USB host with a standard USB-A port
the port SHOULD use the micro USB form factor on the device side. Existing
and new devices that run Android 4.1 are very strongly encouraged to meet
these requirements in Android 4.1
so they wil be able to upgrade to the future
platform releases
the port SHOULD be centered in the middle of an edge. Device implementations
SHOULD either locate the port on the bottom of the device (according to natural
orientation) or enable software screen rotation for al apps (including home
screen), so that the display draws correctly when the device is oriented with the
port at bottom. Existing and new devices that run Android 4.1 are very strongly
encouraged to meet these requirements in Android 4.1
so they wil be able
to upgrade to future platform releases.
if the device has other ports (such as a non-USB charging port) it SHOULD be
on the same edge as the micro-USB port
it MUST al ow a host connected to the device to access the contents of the
shared storage volume using either USB mass storage or Media Transfer
Protocol
it MUST implement the Android Open Accessory API and specification as
documented in the Android SDK documentation, and MUST declare support for
the hardware feature android.hardware.usb.accessory [Resources, 52]
it MUST implement the USB audio class as documented in the Android SDK
documentation [Resources, 66]
it SHOULD implement support for USB battery charging spec ification
[Resources, 64] Existing and new devices that run Android 4.1 are very
strongly encour aged to meet th
ese requirements in Android 4.1 so they
wil be able to upgrade to the future platform releases
If a device implementation includes a USB host port:
it MAY use a non-standard port form factor, but if so MUST ship with a cable or
cables adapting the port to standard USB-A
it MUST implement the Android USB host API as documented in the Android
SDK, and MUST declare support for the hardware feature
android.hardware.usb.host [Resources, 53]
Device implementations MUST implement the Android Debug Bridge. If a device
implementation omits a USB client port, it MUST implement the Android Debug Bridge
via local-area network (such as Ethern et or 802.11)

8. Performance Compatibility
Device implementations MUST meet the key performance metrics of an Android 4.1
compatible device defined in the table below:
Metric
Performance Threshold
Commenti
The fol owing applications
should launch within the
specified time.
The launch time is measured as the
total time to complete loading the
Browser: less than
default activity for the application,
Application
1300ms
including the time it takes to start the
Launch Time
Contacts: less than
Linux process, load the Android
700ms
package into the Dalvik VM, and cal
Settings: less than
onCreate.
700ms
When multiple applications
have been launched, re-
launching an already-
Simultaneous
running application after it

Applications
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, 54] in the Android developer documentation. Device
implementations MUST support instal ation of self-signed applications without
requiring any additional permissions/certificates from any third parties/authorities.
Specifical y, compatible devices MUST support the security mechanisms described in
the fol ow sub-sections.
9.1. Permissions
Device implementations MUST support the Android permissions model as defined in
the Android developer documentation [Resources, 54]. Specifical y, implementations
MUST enforce each permission defined as described in the SDK documentation; no
permissions may be omitted, altered, or i gnored. Impleme ntations 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, 54].
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, 54].
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 instal ed 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. Specifical y:
Alternate runtimes SHOULD instal apps via the PackageManager into separate
Android sandboxes (that is, Linux user IDs, etc.)
Alternate runtimes MAY provide a single Android sandbox shared by al
applications using the alternate runtime
Alternate runtimes and instal ed applications using an alternate runtime MUST
NOT reuse the sandbox of any other app instal ed 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 instal ing 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
wil be able to access that resource. If the runtime environment does not record
application capabilities in this manner, the runtime environment MUST list al
permissions held by the runtime itself when instal ing any application using that runtime.
10. Software Compatibility Testing
Device implementations MUST pass al tests described in this section.
However, note that no software test package is ful y 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 4.1
available from the Android Open Source Project. This wil 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. Additional y, device implementers SHOULD use the
r eference imple mentation 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 wil be versioned independently of this Compatibility
Definition, and multiple revisions of the CTS may be released for Android 4.1. Device
implementations MUST pass the latest CTS version available at the time the device
software is completed.
10.2. CTS Verifier
Device implementations MUST correctly execute al 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 al 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. Specifical y,
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 fol owing open
source applications:
The "Apps for Android" applications [Re sources, 55]
Replica Island (available in Android Market)
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
preinstal ed on the device. For instance, any of the fol owing approaches wil 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. That is,
the update mechanism MUST preserve application private data and application
shared data. Note that the upstream Android software includes an update mechanism
that satisfies this requirement.
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 ful y 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. Instal BluetoothChat.apk on the known-good device
3. Instal 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 cal s finish()), and implicitly sent
to background (via the user pressing Home.) Each test sequence MUST be performed
as described.