1. Introduzione

Questo documento elenca i requisiti che devono essere soddisfatti affinché i dispositivi siano compatibili con Android 6.0.

L'uso di "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY" e "OPTIONAL" è conforme a IETF standard definito in RFC2119 [ Risorse, 1 ].

Come utilizzato in questo documento, un "implementatore del dispositivo" o "implementatore" è una persona o un'organizzazione che sviluppa una soluzione hardware/software con Android 6.0. Una “implementazione del dispositivo” o “implementazione” è la soluzione hardware/software così sviluppata.

Per essere considerate compatibili con Android 6.0, le implementazioni del dispositivo DEVONO soddisfare i requisiti presentati nella presente Definizione di compatibilità, inclusi eventuali documenti incorporati tramite riferimento.

Laddove questa definizione o i test software descritti nella sezione 10 siano silenziosi, ambigui o incompleti, è responsabilità dell'implementatore del dispositivo garantire la compatibilità con le implementazioni esistenti.

Per questo motivo, il progetto Android Open Source [ Risorse, 2 ] è sia l'implementazione di riferimento che quella preferita di Android. Agli implementatori dei dispositivi SI RACCOMANDA FORTEMENTE di basare le proprie implementazioni nella massima misura possibile sul codice sorgente "upstream" disponibile dal progetto Android Open Source. Sebbene alcuni componenti possano ipoteticamente essere sostituiti con implementazioni alternative, SI CONSIGLIA FORTEMENTE di non seguire questa pratica, poiché superare i test del software diventerà sostanzialmente più difficile. È responsabilità dell'implementatore garantire la piena compatibilità comportamentale con l'implementazione Android standard, inclusa e oltre la Compatibility Test Suite. Infine, si noti che alcune sostituzioni e modifiche di componenti sono esplicitamente vietate da questo documento.

Molte delle risorse elencate nella sezione 14 derivano direttamente o indirettamente dall'SDK di Android e saranno funzionalmente identiche alle informazioni contenute nella documentazione dell'SDK. In tutti i casi in cui la presente Definizione di compatibilità o la Suite di test di compatibilità non sono d'accordo con la documentazione dell'SDK, la documentazione dell'SDK è considerata autorevole. Tutti i dettagli tecnici forniti nei riferimenti inclusi nella sezione 14 sono considerati per inclusione parte della presente Definizione di compatibilità.

2. Tipi di dispositivi

Sebbene il progetto Android Open Source sia stato utilizzato nell'implementazione di una varietà di tipi di dispositivi e fattori di forma, molti aspetti dell'architettura e dei requisiti di compatibilità sono stati ottimizzati per i dispositivi portatili. A partire da Android 5.0, il progetto Android Open Source mira ad abbracciare una più ampia varietà di tipi di dispositivi come descritto in questa sezione.

Il dispositivo portatile Android si riferisce a un'implementazione del dispositivo Android che viene generalmente utilizzata tenendolo in mano, come lettori mp3, telefoni e tablet. Implementazioni del dispositivo portatile Android:

• DEVE avere un touchscreen incorporato nel dispositivo.
• DEVE avere una fonte di alimentazione che garantisca mobilità, come una batteria.

Per dispositivo Android Television si intende un'implementazione del dispositivo Android che costituisce un'interfaccia di intrattenimento per la fruizione di media digitali, film, giochi, app e/o TV in diretta per utenti seduti a circa tre metri di distanza (un'interfaccia utente "appoggiata allo schienale" o "interfaccia utente da 10 piedi") "). Dispositivi TV Android:

• DEVE avere uno schermo incorporato OPPURE includere una porta di uscita video, come VGA, HDMI o una porta wireless per il display.
• DEVE dichiarare le funzionalità android.software.leanback e android.hardware.type.television [ Risorse, 3 ].

Per dispositivo Android Watch si intende un'implementazione del dispositivo Android destinata ad essere indossata sul corpo, magari al polso, e:

• DEVE avere uno schermo con una lunghezza diagonale fisica compresa tra 1,1 e 2,5 pollici.
• DEVE dichiarare la funzionalità android.hardware.type.watch.
• DEVE supportare uiMode = UI_MODE_TYPE_WATCH [ Risorse, 4 ].

L'implementazione di Android Automotive si riferisce a un'unità principale del veicolo che esegue Android come sistema operativo per parte o tutte le funzionalità del sistema e/o di infotainment. Implementazioni Android Automotive:

• DEVE dichiarare la funzionalità android.hardware.type.automotive.
• DEVE supportare uiMode = UI_MODE_TYPE_CAR [ Risorse, 5 ].

Tutte le implementazioni di dispositivi Android che non rientrano in nessuno dei tipi di dispositivi sopra indicati DEVONO comunque soddisfare tutti i requisiti presenti in questo documento per essere compatibili con Android 6.0, a meno che il requisito non sia esplicitamente descritto come applicabile solo a uno specifico tipo di dispositivo Android di cui sopra.

2.1 Configurazioni del dispositivo

Questo è un riepilogo delle principali differenze nella configurazione hardware in base al tipo di dispositivo. (Le celle vuote indicano un "MAGGIO"). Non tutte le configurazioni sono trattate in questa tabella; vedere le sezioni hardware pertinenti per maggiori dettagli.

Categoria	Caratteristica	Sezione	Palmare	Televisione	Orologio	Settore automobilistico	Altro
Ingresso	Tasto direzionale	7.2.2. Navigazione senza tocco		DOVERE
	Touch screen	7.2.4. Ingresso sul touchscreen	DOVERE		DOVERE		DOVREBBE
	Microfono	7.8.1. Microfono	DOVERE	DOVREBBE	DOVERE	DOVERE	DOVREBBE
Sensori	Accelerometro	7.3.1 Accelerometro	DOVREBBE		DOVREBBE		DOVREBBE
	GPS	7.3.3. GPS	DOVREBBE			DOVREBBE
Connettività	Wifi	7.4.2. IEEE 802.11	DOVREBBE	DOVERE		DOVREBBE	DOVREBBE
	Wi-Fi diretto	7.4.2.1. Wi-Fi diretto	DOVREBBE	DOVREBBE			DOVREBBE
	Bluetooth	7.4.3. Bluetooth	DOVREBBE	DOVERE	DOVERE	DOVERE	DOVREBBE
	Bluetooth a basso consumo energetico	7.4.3. Bluetooth	DOVREBBE	DOVERE	DOVREBBE	DOVREBBE	DOVREBBE
	Modalità periferica/host USB	7.7. USB	DOVREBBE			DOVREBBE	DOVREBBE
Produzione	Porte per altoparlanti e/o uscita audio	7.8.2. Uscita audio	DOVERE	DOVERE		DOVERE	DOVERE

3. Software

3.1. Compatibilità API gestita

L'ambiente di esecuzione del bytecode Dalvik gestito è il veicolo principale per le applicazioni Android. L'API (Application Programming Interface) Android è l'insieme di interfacce della piattaforma Android esposte alle applicazioni in esecuzione nell'ambiente di runtime gestito. Le implementazioni del dispositivo DEVONO fornire implementazioni complete, inclusi tutti i comportamenti documentati, di qualsiasi API documentata esposta dall'SDK di Android [ Risorse, 6 ] o qualsiasi API decorata con il marcatore "@SystemApi" nel codice sorgente Android upstream.

Le implementazioni del dispositivo NON DEVONO omettere alcuna API gestita, alterare le interfacce o le firme API, deviare dal comportamento documentato o includere no-op, tranne dove specificamente consentito dalla presente Definizione di compatibilità.

Questa definizione di compatibilità consente di omettere dalle implementazioni del dispositivo alcuni tipi di hardware per i quali Android include API. In questi casi, le API DEVONO essere ancora presenti e comportarsi in modo ragionevole. Vedere la sezione 7 per i requisiti specifici per questo scenario.

3.2. Compatibilità API soft

Oltre alle API gestite della sezione 3.1 , Android include anche una significativa API "soft" solo in fase di runtime, sotto forma di intenti, autorizzazioni e aspetti simili delle applicazioni Android che non possono essere applicati in fase di compilazione dell'applicazione.

3.2.1. Autorizzazioni

Gli implementatori del dispositivo DEVONO supportare e applicare tutte le costanti di autorizzazione come documentato dalla pagina di riferimento sulle autorizzazioni [ Risorse, 7 ]. Tieni presente che la sezione 9 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 [ Resources, 8 ] che hanno lo scopo di descrivere il dispositivo corrente. Per fornire valori coerenti e significativi tra le implementazioni del dispositivo, la tabella seguente include ulteriori restrizioni sui formati di questi valori a cui le implementazioni del dispositivo DEVONO conformarsi.

Parametro	Dettagli
VERSIONE.RELEASE	La versione del sistema Android attualmente in esecuzione, in formato leggibile dall'uomo. Questo campo DEVE avere uno dei valori stringa definiti in [ Risorse, 9 ].
VERSIONE.SDK	La versione del sistema Android attualmente in esecuzione, in un formato accessibile al codice dell'applicazione di terze parti. Per Android 6.0, questo campo DEVE avere il valore intero 23.
VERSIONE.SDK_INT	La versione del sistema Android attualmente in esecuzione, in un formato accessibile al codice dell'applicazione di terze parti. Per Android 6.0, questo campo DEVE avere il valore intero 23.
VERSIONE.INCREMENTALE	Un valore scelto dall'implementatore del dispositivo che designa la build specifica del sistema Android attualmente in esecuzione, in formato leggibile dall'uomo. Questo valore NON DEVE essere riutilizzato per build diverse rese disponibili agli utenti finali. Un utilizzo tipico di questo campo è indicare quale numero di build o identificatore di modifica del controllo del codice sorgente è stato utilizzato per generare la build. Non ci sono requisiti sul formato specifico di questo campo, tranne che NON DEVE essere null o una stringa vuota ("").
ASSE	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 quello di indicare la revisione specifica della scheda che alimenta il dispositivo. Il valore di questo campo DEVE essere codificabile come ASCII a 7 bit e corrispondere all'espressione regolare "^[a-zA-Z0-9_-]+$".
MARCA	Un valore che riflette il nome del marchio associato al dispositivo come noto agli utenti finali. DEVE essere in un formato leggibile dall'uomo e DOVREBBE rappresentare il produttore del dispositivo o il marchio aziendale con cui il dispositivo è commercializzato. Il valore di questo campo DEVE essere codificabile come ASCII a 7 bit e corrispondere all'espressione regolare "^[a-zA-Z0-9_-]+$".
SUPPORTATO_ABIS	Il nome del set di istruzioni (tipo CPU + convenzione ABI) del codice nativo. Vedere la sezione 3.3. Compatibilità API nativa .
SUPPORTATO_32_BIT_ABIS	Il nome del set di istruzioni (tipo CPU + convenzione ABI) del codice nativo. Vedere la sezione 3.3. Compatibilità API nativa .
SUPPORTATO_64_BIT_ABIS	Il nome del secondo set di istruzioni (tipo CPU + convenzione ABI) del codice nativo. Vedere la sezione 3.3. Compatibilità API nativa .
CPU_ABI	Il nome del set di istruzioni (tipo CPU + convenzione ABI) del codice nativo. Vedere la sezione 3.3. Compatibilità API nativa .
CPU_ABI2	Il nome del secondo set di istruzioni (tipo CPU + convenzione ABI) del codice nativo. Vedere la sezione 3.3. Compatibilità API nativa .
DISPOSITIVO	Un valore scelto dall'implementatore del dispositivo contenente il nome di sviluppo o il nome in codice che identifica la configurazione delle caratteristiche hardware e il design industriale del dispositivo. Il valore di questo campo DEVE essere codificabile come ASCII a 7 bit e corrispondere all'espressione regolare "^[a-zA-Z0-9_-]+$".
IMPRONTA DIGITALE	Una stringa che identifica in modo univoco questa build. DOVREBBE essere ragionevolmente leggibile dall'uomo. DEVE seguire questo modello: $(MARCA)/$(PRODOTTO)/ $(DISPOSITIVO):$(VERSIONE.RELEASE)/$(ID)/$(VERSIONE.INCREMENTALE):$(TIPO)/$(TAG) Per esempio: acme/mioprodotto/ miodispositivo:6.0/LMYXX/3359:userdebug/test-keys L'impronta digitale NON DEVE includere caratteri di spazi bianchi. Se altri campi inclusi nel modello precedente contengono caratteri di spazio bianco, DEVONO essere sostituiti nell'impronta digitale creata con un altro carattere, ad esempio il carattere di sottolineatura ("_"). Il valore di questo campo DEVE essere codificabile come ASCII a 7 bit.
HARDWARE	Il nome dell'hardware (dalla riga di comando del kernel o /proc). DOVREBBE essere ragionevolmente leggibile dall'uomo. Il valore di questo campo DEVE essere codificabile come ASCII a 7 bit e corrispondere all'espressione regolare "^[a-zA-Z0-9_-]+$".
OSPITE	Una stringa che identifica in modo univoco l'host su cui è stata creata la build, in formato leggibile dall'uomo. Non ci sono requisiti sul formato specifico di questo campo, tranne che NON DEVE essere null o una stringa vuota ("").
ID	Un identificatore scelto dall'implementatore del dispositivo per fare riferimento a una versione specifica, in formato leggibile dall'uomo. Questo campo può essere uguale a android.os.Build.VERSION.INCREMENTAL, ma DOVREBBE essere un valore sufficientemente significativo per consentire agli utenti finali di distinguere tra build di software. Il valore di questo campo DEVE essere codificabile come ASCII a 7 bit e corrispondere all'espressione regolare "^[a-zA-Z0-9._-]+$".
PRODUTTORE	Il nome commerciale del produttore dell'attrezzatura originale (OEM) del prodotto. Non ci sono requisiti sul formato specifico di questo campo, tranne che NON DEVE essere null o una stringa vuota ("").
MODELLO	Un valore scelto dall'implementatore del dispositivo contenente il nome del dispositivo noto all'utente finale. 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 che NON DEVE essere null o una stringa vuota ("").
PRODOTTO	Un valore scelto dall'implementatore del dispositivo contenente il nome di sviluppo o il nome in codice del prodotto specifico (SKU) che DEVE essere univoco all'interno dello stesso marchio. DEVE essere leggibile dall'uomo, ma non è necessariamente destinato alla visualizzazione da parte degli utenti finali. Il valore di questo campo DEVE essere codificabile come ASCII a 7 bit e corrispondere all'espressione regolare "^[a-zA-Z0-9_-]+$".
SERIALE	Un numero di serie hardware, che DEVE essere disponibile e univoco su tutti i dispositivi con lo stesso MODELLO e PRODUTTORE. Il valore di questo campo DEVE essere codificabile come ASCII a 7 bit e corrispondere all'espressione regolare "^([a-zA-Z0-9]{6,20})$".
TAG	Un elenco di tag separati da virgole scelti dall'implementatore del dispositivo che distingue ulteriormente la build. Questo campo DEVE avere uno dei valori corrispondenti alle tre tipiche configurazioni di firma della piattaforma Android: release-keys, dev-keys, test-keys.
TEMPO	Un valore che rappresenta il timestamp di quando si è verificata la compilazione.
TIPO	Un valore scelto dall'implementatore del dispositivo che specifica la configurazione di runtime della build. Questo campo DEVE avere uno dei valori corrispondenti alle tre tipiche configurazioni di runtime di Android: user, userdebug o eng.
UTENTE	Un nome o un ID utente dell'utente (o dell'utente automatizzato) che ha generato la build. Non ci sono requisiti sul formato specifico di questo campo, tranne che NON DEVE essere null o una stringa vuota ("").
SICUREZZA_PATCH	Un valore che indica il livello della patch di sicurezza di una build. DEVE significare che la build include tutte le patch di sicurezza rilasciate tramite il Bollettino di sicurezza pubblica Android designato. DEVE essere nel formato [AAAA-MM-GG], corrispondente a una delle stringhe del livello di patch di sicurezza Android dei bollettini di pubblica sicurezza , ad esempio "2015-11-01".
BASE_OS	Un valore che rappresenta il parametro FINGERPRINT della build che per il resto è identica a questa build ad eccezione delle patch fornite nel Bollettino pubblico sulla sicurezza di Android. DEVE riportare il valore corretto e se tale build non esiste, riporta una stringa vuota ("").

3.2.3. Compatibilità degli intenti

Le implementazioni del dispositivo DEVONO rispettare il sistema di intenti ad accoppiamento lento di Android, come descritto nelle sezioni seguenti. Con "onorato" si intende che l'implementatore del dispositivo DEVE fornire un'attività o un servizio Android che specifica un filtro di intenti corrispondente che si lega e implementa il comportamento corretto per ciascun modello di intenti specificato.

3.2.3.1. Intenti dell'applicazione principale

Gli intenti Android consentono ai componenti dell'applicazione di richiedere funzionalità da altri componenti Android. Il progetto Android upstream include un elenco di applicazioni considerate applicazioni Android principali, che implementa diversi modelli di intenti per eseguire azioni comuni. Le principali applicazioni Android sono:

• Orologio da tavolo
• Navigatore
• Calendario
• Contatti
• Galleria
• Ricerca globale
• Lanciatore
• Musica
• Impostazioni

Le implementazioni dei dispositivi DOVREBBERO includere le applicazioni Android principali, a seconda dei casi, ma DEVE includere un componente che implementa gli stessi modelli di intenti definiti da tutti i componenti di attività o servizio "pubblici" di queste applicazioni Android principali. Tieni presente che i componenti Attività o Servizio sono considerati “pubblici” quando l'attributo android:exported è assente o ha il valore true.

3.2.3.2. Risoluzione dell'intento

Poiché Android è una piattaforma estensibile, le implementazioni del dispositivo DEVONO consentire che ogni modello di intent a cui si fa riferimento nella sezione 3.2.3.1 venga sovrascritto da applicazioni di terze parti. L'implementazione open source Android upstream lo consente per impostazione predefinita; gli implementatori del dispositivo NON DEVONO attribuire privilegi speciali all'utilizzo di questi modelli di intenti da parte delle applicazioni di sistema, né impedire ad applicazioni di terze parti di vincolarsi e assumere il controllo di questi modelli. Questo divieto include specificamente, ma non è limitato alla disabilitazione dell'interfaccia utente "Scelta" che consente all'utente di selezionare tra più applicazioni che gestiscono tutte lo stesso modello di intenti.

Le implementazioni del dispositivo DEVONO fornire un'interfaccia utente affinché gli utenti possano modificare l'attività predefinita per gli intenti.

Tuttavia, le implementazioni del dispositivo POSSONO fornire attività predefinite per modelli URI specifici (ad esempio http://play.google.com) quando l'attività predefinita fornisce un attributo più specifico per l'URI dei dati. Ad esempio, un modello di filtro di intenti che specifica l'URI dei dati "http://www.android.com" è più specifico del modello di intenti principale del browser per "http://".

Android include anche un meccanismo che consente alle app di terze parti di dichiarare un comportamento di collegamento di app predefinito autorevole per determinati tipi di intenti URI web [ Risorse, 140 ]. Quando tali dichiarazioni autorevoli vengono definite nei modelli di filtro degli intenti di un'app, le implementazioni del dispositivo:

• DEVE tentare di convalidare eventuali filtri di intenti eseguendo i passaggi di convalida definiti nella specifica Digital Asset Links [ Risorse, 141 ] come implementato dal Gestore pacchetti nel progetto Android Open Source upstream.
• DEVE tentare la convalida dei filtri di intenti durante l'installazione dell'applicazione e impostare tutti i filtri di intenti UIR convalidati con successo come gestori di app predefiniti per i relativi UIR.
• PUÒ impostare filtri di intenti URI specifici come gestori di app predefiniti per i loro URI, se vengono verificati con successo ma altri filtri URI candidati falliscono la verifica. Se un'implementazione del dispositivo fa ciò, DEVE fornire le sovrascritture del modello per URI appropriate all'utente nel menu delle impostazioni.
• DEVE fornire all'utente i controlli Collegamenti app per app nelle Impostazioni come segue:
  • L'utente DEVE essere in grado di sovrascrivere in modo olistico il comportamento predefinito dei collegamenti dell'app affinché un'app sia: sempre aperta, chiedi sempre o non aprire mai, che deve applicarsi allo stesso modo a tutti i filtri di intenti dell'URI candidato.
  • L'utente DEVE essere in grado di vedere un elenco dei filtri di intenti URI candidati.
  • L'implementazione del dispositivo PUÒ fornire all'utente la possibilità di sovrascrivere filtri di intenti URI candidati specifici che sono stati verificati con successo, in base al filtro per intent.
  • L'implementazione del dispositivo DEVE fornire agli utenti la possibilità di visualizzare e sovrascrivere filtri di intenti URI candidati specifici se l'implementazione del dispositivo consente ad alcuni filtri di intenti URI candidati di riuscire nella verifica mentre altri possono fallire.

3.2.3.3. Spazi dei nomi di intenti

Le implementazioni del dispositivo NON DEVONO includere alcun componente Android che rispetti qualsiasi nuovo intento o modello di intento di trasmissione utilizzando un'AZIONE, una CATEGORIA o un'altra stringa di chiave nello spazio dei nomi android.* o com.android.*. Gli implementatori del dispositivo NON DEVONO includere componenti Android che rispettano nuovi intenti o modelli di intenti di trasmissione utilizzando un'AZIONE, una CATEGORIA o un'altra stringa chiave in uno spazio pacchetto appartenente a un'altra organizzazione. Gli implementatori del dispositivo NON DEVONO alterare o estendere nessuno dei modelli di intenti utilizzati dalle app principali elencate nella sezione 3.2.3.1 . Le implementazioni dei dispositivi POSSONO includere modelli di intenti che utilizzano spazi dei nomi chiaramente e ovviamente associati alla propria organizzazione. Questo divieto è analogo a quello specificato per le classi del linguaggio Java nella sezione 3.6 .

3.2.3.4. Intenti di trasmissione

Le applicazioni di terze parti si affidano alla piattaforma per trasmettere determinati intenti per notificare loro cambiamenti nell'ambiente hardware o software. I dispositivi compatibili con Android DEVONO trasmettere gli intenti di trasmissione pubblica in risposta agli eventi di sistema appropriati. Gli intenti di trasmissione sono descritti nella documentazione dell'SDK.

3.2.3.5. Impostazioni predefinite dell'app

Android include impostazioni che forniscono agli utenti un modo semplice per selezionare le applicazioni predefinite, ad esempio per la schermata Home o gli SMS. Laddove opportuno, le implementazioni del dispositivo DEVONO fornire un menu di impostazioni simile ed essere compatibili con il modello di filtro intent e i metodi API descritti nella documentazione dell'SDK come di seguito.

Implementazioni del dispositivo:

• DEVE rispettare l'intento android.settings.HOME_SETTINGS di mostrare un menu di impostazioni dell'app predefinito per la schermata principale, se l'implementazione del dispositivo riporta android.software.home_screen [ Risorse, 10 ]
• DEVE fornire un menu di impostazioni che chiamerà l'intento android.provider.Telephony.ACTION_CHANGE_DEFAULT per mostrare una finestra di dialogo per modificare l'applicazione SMS predefinita, se l'implementazione del dispositivo riporta android.hardware.telephony [ Risorse, 11 ]
• DEVE rispettare l'intento android.settings.NFC_PAYMENT_SETTINGS di mostrare un menu di impostazioni dell'app predefinito per Tocca e paga, se l'implementazione del dispositivo riporta android.hardware.nfc.hce [ Risorse, 10 ]

3.3. Compatibilità API nativa

3.3.1. Interfacce binarie dell'applicazione

Il bytecode Dalvik gestito può richiamare il codice nativo fornito nel file .apk dell'applicazione 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 una serie di interfacce binarie applicative (ABI) nell'NDK di Android. Le implementazioni del dispositivo DEVONO essere compatibili con uno o più ABI definiti e DEVONO implementare la compatibilità con Android NDK, come di seguito.

Se l'implementazione di un dispositivo include il supporto per un'ABI Android, essa:

• DEVE includere il supporto per il codice in esecuzione nell'ambiente gestito per richiamare il codice nativo, utilizzando la semantica JNI (Java Native Interface) standard
• DEVE essere compatibile con il codice sorgente (ovvero compatibile con l'intestazione) e compatibile con il codice binario (per ABI) con ciascuna libreria richiesta nell'elenco seguente
• DEVE supportare l'equivalente ABI a 32 bit se è supportata una qualsiasi ABI a 64 bit
• DEVE riportare accuratamente l'Application Binary Interface (ABI) nativa supportata dal dispositivo, tramite i parametri android.os.Build.SUPPORTED_ABIS, android.os.Build.SUPPORTED_32_BIT_ABIS e android.os.Build.SUPPORTED_64_BIT_ABIS, ciascuno un elenco separato da virgole di ABI ordinati dal più al meno preferito
• DEVE riportare, tramite i parametri di cui sopra, solo gli ABI documentati e descritti nell'ultima versione della documentazione di gestione ABI NDK di Android [ Risorse, 12 ] e DEVE includere il supporto per l'estensione Advanced SIMD (nota anche come NEON) [ Risorse, 13 ]
• DOVREBBE essere creato utilizzando il codice sorgente e i file di intestazione disponibili nel progetto Android Open Source upstream

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.x)
• libGLESv2.so (OpenGL ES 2.0)
• libGLESv3.so (OpenGL ES 3.x)
• libEGL.so (gestione superficie OpenGL nativa)
• libjnigraphics.so
• libOpenSLES.so (supporto audio OpenSL ES 1.0.1)
• libOpenMAXAL.so (supporto OpenMAX AL 1.0.1)
• libandroid.so (supporto attività Android nativo)
• libmediandk.so (supporto API multimediali native)
• Supporto per OpenGL, come descritto di seguito

Tieni presente che le versioni future di Android NDK potrebbero introdurre il supporto per ABI aggiuntivi. Se l'implementazione di un dispositivo non è compatibile con un'ABI predefinita esistente, NON DEVE segnalare il supporto per alcuna ABI.

Tieni presente che le implementazioni del dispositivo DEVONO includere libGLESv3.so e DEVE essere collegato simbolicamente (collegamento simbolico) a libGLESv2.so. a sua volta, DEVE esportare tutti i simboli di funzione OpenGL ES 3.1 e Android Extension Pack [ Risorse, 14 ] come definito nella versione NDK android-21. Anche se devono essere presenti tutti i simboli, devono essere completamente implementate solo le funzioni corrispondenti per le versioni e le estensioni OpenGL ES effettivamente supportate dal dispositivo.

Le implementazioni del dispositivo, se includono una libreria nativa con il nome libvulkan.so, DEVONO esportare simboli di funzione e fornire un'implementazione dell'API Vulkan 1.0 e delle estensioni VK_KHR_surface, VK_KHR_swapchain e VK_KHR_android_surface come definito dal Gruppo Khronos e superare i test di conformità Khronos.

La compatibilità del codice nativo è impegnativa. Per questo motivo, agli implementatori del dispositivo SI RACCOMANDA FORTEMENTE di utilizzare le implementazioni delle librerie sopra elencate dal progetto Android Open Source upstream.

3.3.2. Compatibilità del codice nativo ARM a 32 bit

L'architettura ARMv8 depreca diverse operazioni della CPU, comprese alcune operazioni utilizzate nel codice nativo esistente. Sui dispositivi ARM a 64 bit, le seguenti operazioni deprecate DEVONO rimanere disponibili per il codice ARM nativo a 32 bit, tramite il supporto nativo della CPU o tramite l'emulazione software:

• Istruzioni SWP e SWPB
• Istruzione SETEND
• Operazioni con barriera CP15ISB, CP15DSB e CP15DMB

Le versioni legacy di Android NDK utilizzavano /proc/cpuinfo per scoprire le funzionalità della CPU dal codice nativo ARM a 32 bit. Per compatibilità con le applicazioni create utilizzando questo NDK, i dispositivi DEVONO includere le seguenti righe in /proc/cpuinfo quando viene letto dalle applicazioni ARM a 32 bit:

• "Caratteristiche: ", seguito da un elenco di eventuali funzionalità opzionali della CPU ARMv7 supportate dal dispositivo
• "Architettura CPU:", seguito da un numero intero che descrive l'architettura ARM supportata più alta del dispositivo (ad esempio, "8" per i dispositivi ARMv8)

Questi requisiti si applicano solo quando /proc/cpuinfo viene letto da applicazioni ARM a 32 bit. I dispositivi NON DOVREBBERO alterare /proc/cpuinfo quando letti da applicazioni ARM o non ARM a 64 bit.

3.4. Compatibilità Web

3.4.1. Compatibilità WebView

La funzionalità della piattaforma android.software.webview DEVE essere segnalata su qualsiasi dispositivo che fornisce un'implementazione completa dell'API android.webkit.WebView e NON DEVE essere segnalata su dispositivi senza un'implementazione completa dell'API. L'implementazione Android Open Source utilizza il codice del progetto Chromium per implementare android.webkit.WebView [ Risorse, 15 ]. Poiché non è possibile sviluppare una suite di test completa per un sistema di rendering web, gli implementatori del dispositivo DEVONO utilizzare la specifica build upstream di Chromium nell'implementazione WebView. Nello specifico:

• Le implementazioni del dispositivo android.webkit.WebView DEVONO essere basate sulla build Chromium del progetto Android Open Source upstream per Android 6.0. Questa build include un insieme specifico di funzionalità e correzioni di sicurezza per WebView [ Risorse, 16 ].
• La stringa dello user agent riportata da WebView DEVE essere in questo formato:

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

  • Il valore della stringa $(VERSION) DEVE essere uguale al valore di android.os.Build.VERSION.RELEASE.
  • Il valore della stringa $(MODEL) DEVE essere uguale al valore di android.os.Build.MODEL.
  • Il valore della stringa $(BUILD) DEVE essere uguale al valore di android.os.Build.ID.
  • Il valore della stringa $(CHROMIUM_VER) DEVE essere la versione di Chromium nel progetto Android Open Source upstream.
  • Le implementazioni del dispositivo POSSONO omettere Mobile nella stringa dell'agente utente.

Il componente WebView DOVREBBE includere il supporto per quante più funzionalità HTML5 possibili e, se supporta la funzionalità, DOVREBBE essere conforme alle specifiche HTML5 [ Risorse, 17 ].

3.4.2. Compatibilità del browser

Il browser autonomo PUÒ essere basato su una tecnologia browser diversa da WebKit. Tuttavia, anche se viene utilizzata un'applicazione browser alternativa, il componente android.webkit.WebView fornito alle applicazioni di terze parti DEVE essere basato su WebKit, come descritto nella sezione 3.4.1 .

Le implementazioni POSSONO fornire una stringa dell'agente utente personalizzata nell'applicazione browser autonoma.

L'applicazione browser autonoma (basata sull'applicazione WebKit Browser upstream o su un sostituto di terze parti) DOVREBBE includere il supporto per la maggior parte possibile di HTML5 [ Risorse, 17 ]. Come minimo, le implementazioni del dispositivo DEVONO supportare ciascuna di queste API associate a HTML5:

• cache dell'applicazione/operazione offline [ Risorse, 18 ]
• il tag <video> [ Risorse, 19 ]
• geolocalizzazione [ Risorse, 20 ]

Inoltre, le implementazioni del dispositivo DEVONO supportare l'API di webstorage HTML5/W3C [ Risorse, 21 ] e DOVREBBERO supportare l'API IndexedDB HTML5/W3C [ Risorse, 22 ]. Tieni presente che poiché gli organismi di standardizzazione dello sviluppo web stanno passando a favorire IndexedDB rispetto al webstorage, si prevede che IndexedDB diventi un componente richiesto in una futura versione di Android.

3.5. Compatibilità comportamentale dell'API

I comportamenti di ciascuno dei tipi di API (gestita, soft, nativa e web) devono essere coerenti con l'implementazione preferita del progetto Android Open Source upstream [ Risorse, 2 ]. 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 di 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. La Compatibility Test Suite (CTS) verifica la compatibilità comportamentale di parti significative della piattaforma, ma non di tutte. È responsabilità dell'implementatore garantire la compatibilità comportamentale con il progetto Android Open Source. Per questo motivo, gli implementatori di dispositivi dovrebbero utilizzare il codice sorgente disponibile tramite il progetto open source Android ove possibile, piuttosto che reimplementare parti significative del sistema.

3.6. Spazi dei nomi API

Android segue le convenzioni dello spazio dei nomi del pacchetto e della classe definite dal linguaggio di programmazione Java. Per garantire la compatibilità con applicazioni di terze parti, gli implementari del dispositivo non devono apportare modifiche proibite (vedi sotto) a questi spazi dei nomi dei pacchetti:

• Giava.*
• Javax.*
• sole.*
• Android.*
• com.android.*

Le modifiche proibite includono :

• Le implementazioni del dispositivo non devono modificare le API esposte pubblicamente sulla piattaforma Android modificando qualsiasi metodo o firme di classe o rimuovendo le classi o i campi di classe.
• Gli implementari del dispositivo possono modificare l'implementazione sottostante delle API, ma tali modifiche non devono influire sul comportamento dichiarato e la firma in lingua Java di qualsiasi API esposta pubblicamente.
• Gli implementari del dispositivo non devono aggiungere elementi esposti pubblicamente (come classi o interfacce o campi o metodi per classi o interfacce esistenti) alle API sopra.

Un "elemento esposto pubblicamente" è un costrutto che non è decorato con il marcatore "@Hide" utilizzato nel codice sorgente Android a monte. In altre parole, gli implementari del dispositivo non devono esporre nuove API o alterare le API esistenti negli spazi dei nomi sopra indicati. Gli implementatori di dispositivi possono apportare modifiche solo interne, ma tali 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 uno spazio dei nomi di proprietà o riferirsi a un'altra organizzazione. Ad esempio, gli implementatori di dispositivi non devono aggiungere API al COM.Google.* O spazio dei nomi simile: solo Google può farlo. Allo stesso modo, Google non deve aggiungere API agli spazi dei nomi di altre società. Inoltre, se un'implementazione del dispositivo include API personalizzate al di fuori dello spazio dei nomi Android standard, quelle API devono essere confezionate in una libreria condivisa Android in modo che solo le app che le usano esplicitamente (tramite LT; usi-Librarygt; meccanismo) siano influenzate dall'aumento della memoria utilizzo di tali API.

Se un implementatore del dispositivo propone di migliorare uno degli spazi dei nomi dei pacchetti sopra (ad esempio aggiungendo nuove funzionalità utili a un'API esistente o aggiungendo una nuova API), l'implementatore dovrebbe visitare fonte.android.com e iniziare il processo per contribuire alle modifiche e Codice, secondo le informazioni su quel sito.

Si noti che le restrizioni sopra corrispondono alle convenzioni standard per la denominazione delle API nel linguaggio di programmazione Java; Questa sezione mira semplicemente a rafforzare tali convenzioni e renderle vincolanti attraverso l'inclusione in questa definizione di compatibilità.

3.7. Compatibilità di runtime

Le implementazioni del dispositivo devono supportare l'intero formato Dalvik Executable (DEX) e la specifica e semantica Dalvik bytecode [ risorse, 23 ]. Gli implementatori di dispositivi dovrebbero utilizzare l'ART, l'implementazione a monte del formato eseguibile Dalvik e il sistema di gestione dei pacchetti dell'implementazione di riferimento.

Le implementazioni del dispositivo devono configurare i runtimes Dalvik per allocare la memoria in conformità con la piattaforma Android a monte e, come specificato dalla tabella seguente. (Vedere la 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 le implementazioni del dispositivo possono allocare più memoria per applicazione.

Layout dello schermo	Densità dello schermo	Memoria minima dell'applicazione
Orologio Android	120 dpi (LDPI)	32 MB
	160 dpi (MDPI)
	213 dpi (TVDPI)
	240 dpi (HDPI)	36 MB
	280 dpi (280dpi)
	320 dpi (XHDPI)	48 MB
	360 dpi (360dpi)
	400 dpi (400dpi)	56 MB
	420 dpi (420dpi)	64 MB
	480 dpi (xxhdpi)	88 MB
	560 dpi (560dpi)	112 MB
	640 dpi (xxxhdpi)	154 MB
piccolo/normale	120 dpi (LDPI)	32 MB
	160 dpi (MDPI)
	213 dpi (TVDPI)	48 MB
	240 dpi (HDPI)
	280 dpi (280dpi)
	320 dpi (XHDPI)	80 MB
	360 dpi (360dpi)
	400 dpi (400dpi)	96 MB
	420 dpi (420dpi)	112 MB
	480 dpi (xxhdpi)	128 MB
	560 dpi (560dpi)	192 MB
	640 dpi (xxxhdpi)	256 MB
grande	120 dpi (LDPI)	32 MB
	160 dpi (MDPI)	48 MB
	213 dpi (TVDPI)	80 MB
	240 dpi (HDPI)
	280 dpi (280dpi)	96 MB
	320 dpi (XHDPI)	128 MB
	360 dpi (360dpi)	160 MB
	400 dpi (400dpi)	192 MB
	420 dpi (420dpi)	228 MB
	480 dpi (xxhdpi)	256 MB
	560 dpi (560dpi)	384 MB
	640 dpi (xxxhdpi)	512 MB
xlarge	120 dpi (LDPI)	48 MB
	160 dpi (MDPI)	80 MB
	213 dpi (TVDPI)	96 MB
	240 dpi (HDPI)
	280 dpi (280dpi)	144 MB
	320 dpi (XHDPI)	192 MB
	360 dpi (360dpi)	240 MB
	400 dpi (400dpi)	288 MB
	420 dpi (420dpi)	336 MB
	480 dpi (xxhdpi)	384 MB
	560 dpi (560dpi)	576 MB
	640 dpi (xxxhdpi)	768 MB

3.8. Compatibilità dell'interfaccia utente

3.8.1. Launcher (schermata principale)

Android include un'applicazione di lancio (schermata iniziale) e supporto per applicazioni di terze parti per sostituire il lancio del dispositivo (schermata iniziale). Le implementazioni del dispositivo che consentono alle applicazioni di terze parti di sostituire la schermata domestica del dispositivo devono dichiarare la funzionalità della piattaforma Android.Software.home_screen.

3.8.2. Widget

Android definisce un tipo di componente e l'API e il ciclo di vita corrispondenti che consentono alle applicazioni di esporre un "appwidget" all'utente finale [ risorse, 24 ] una funzionalità che si consiglia fortemente di essere supportata dalle implementazioni del dispositivo portatile. Le implementazioni del dispositivo che supportano i widget di incorporamento nella schermata principale devono soddisfare i seguenti requisiti e dichiarare il supporto per la funzionalità della piattaforma Android.Software.App_Widgets.

• I lanci di dispositivi devono includere il supporto integrato per AppWidgets ed esporre le offerte di interfaccia utente per aggiungere, configurare, visualizzare e rimuovere AppWidget direttamente all'interno del lanciatore.
• Le implementazioni del dispositivo devono essere in grado di rendere i widget di 4 x 4 nella dimensione della griglia standard. Vedere le linee guida per la progettazione del widget app nella documentazione SDK Android [ risorse, 24 ] per i dettagli.
• Le implementazioni del dispositivo che includono il supporto per la schermata di blocco possono supportare i widget dell'applicazione sulla schermata di blocco.

3.8.3. Notifiche

Android include API che consentono agli sviluppatori di avvisare gli utenti di eventi notevoli [ risorse, 25 ], utilizzando le funzionalità hardware e software del dispositivo.

Alcune API consentono alle applicazioni di eseguire notifiche o attirare l'attenzione usando l'hardware: in particolare il suono, le vibrazioni e la luce. Le implementazioni del dispositivo devono supportare le notifiche che utilizzano funzionalità hardware, come descritto nella documentazione SDK e nella misura possibile con l'hardware di implementazione del dispositivo. Ad esempio, se un'implementazione del dispositivo include un vibratore, deve implementare correttamente le API di vibrazione. Se un'implementazione del dispositivo manca di hardware, le API corrispondenti devono essere implementate come no-op. Questo comportamento è ulteriormente dettagliato nella Sezione 7 .

Inoltre, l'implementazione deve rendere correttamente tutte le risorse (icone, file di animazione ecc.) Previsto nelle API [ risorse, 26 ] o nella guida in stile icona della barra dello stato/sistema [ risorse, 27 ], che nel caso di un Il dispositivo televisivo Android include la possibilità di non visualizzare le notifiche. Gli implementatori di dispositivi possono fornire un'esperienza utente alternativa per le notifiche rispetto a quella fornita dall'implementazione open source Android di riferimento; Tuttavia, tali sistemi di notifica alternativa devono supportare le risorse di notifica esistenti, come sopra.

Android include supporto per varie notifiche, come:

• Notifiche ricche . Viste interattive per le notifiche in corso.
• Notifiche heads-up . Visualizzazioni interattive Gli utenti possono agire o liquidare senza lasciare l'app corrente.
• Notifiche di blocco . Notifiche mostrate su una schermata di blocco con controllo granulare sulla visibilità.

Le implementazioni del dispositivo Android, quando tali notifiche sono rese visibili, devono eseguire correttamente notifiche ricche e heads-up e includere il titolo/nome, icona, testo come documentato nelle API Android [ Risorse, 28 ].

Android include API di servizio di listener di notifica che consentono alle app (una volta abilitate esplicitamente dall'utente) di ricevere una copia di tutte le notifiche quando vengono pubblicate o aggiornate. Le implementazioni del dispositivo devono inviare correttamente e prontamente le notifiche nella loro interalità a tutti questi servizi di ascoltatore installati e abilitati per gli utenti, inclusi tutti i metadati collegati all'oggetto di notifica.

3.8.4. Ricerca

Android include API [ Risorse, 29 ] che consentono agli sviluppatori di incorporare la ricerca nelle loro applicazioni ed esporre i dati della loro applicazione nella ricerca del sistema globale. In generale, questa funzionalità è costituita da una singola interfaccia utente a livello di sistema che consente agli utenti di inserire query, visualizzare i suggerimenti come utilizzano gli utenti e visualizzare i risultati. Le API Android consentono agli sviluppatori di riutilizzare questa interfaccia per fornire ricerca all'interno delle proprie app e consentono agli sviluppatori di fornire risultati all'interfaccia utente di ricerca globale comune.

Le implementazioni del dispositivo Android dovrebbero includere la ricerca globale, una singola interfaccia utente di ricerca condivisa a livello di sistema in grado di suggerimenti in tempo reale in risposta all'input dell'utente. Le implementazioni del dispositivo dovrebbero implementare le API che consentono agli sviluppatori di riutilizzare questa interfaccia utente per fornire la ricerca all'interno delle proprie applicazioni. Le implementazioni del dispositivo che implementano l'interfaccia di ricerca globale devono implementare le API che consentono alle applicazioni di terze parti di aggiungere suggerimenti alla casella di ricerca quando viene eseguita in modalità di ricerca globale. Se non vengono installate applicazioni di terze parti che utilizzino questa funzionalità, il comportamento predefinito dovrebbe essere quello di visualizzare i risultati e i suggerimenti dei motori di ricerca Web.

Le implementazioni del dispositivo Android dovrebbero implementare un assistente sul dispositivo per gestire l'azione assist [ Risorse, 30 ].

Android include anche le API di assistenza per consentire alle applicazioni di eleggere quante informazioni sul contesto attuale sono condivise con l'assistente sul dispositivo [ risorse, 31 ]. Le implementazioni del dispositivo a supporto dell'azione assist devono indicare chiaramente all'utente finale quando il contesto viene condiviso visualizzando una luce bianca attorno ai bordi dello schermo. Per garantire una chiara visibilità all'utente finale, l'indicazione deve soddisfare o superare la durata e la luminosità dell'implementazione del progetto open source Android.

3.8.5. Toast

Le applicazioni possono utilizzare l'API "Toast" per visualizzare brevi stringhe non modali per l'utente finale, che scompaiono dopo un breve periodo di tempo [ risorse, 32 ]. Le implementazioni del dispositivo devono visualizzare brindisi dalle applicazioni agli utenti finali in un modo ad alta visibilità.

3.8.6. Temi

Android fornisce "temi" come meccanismo per le applicazioni per applicare stili in un'intera attività o applicazione.

Android include una famiglia a tema "Holo" come insieme di stili definiti per gli sviluppatori di applicazioni se vogliono abbinare l'aspetto del tema Holo come definito dall'SDK Android [ risorse, 33 ]. Le implementazioni del dispositivo non devono alterare nessuno degli attributi del tema Holo esposti alle applicazioni [ risorse, 34 ].

Android include una famiglia di temi "materiale" come insieme di stili definiti per gli sviluppatori di applicazioni da utilizzare se vogliono abbinare l'aspetto e la sensazione del tema del design attraverso l'ampia varietà di diversi tipi di dispositivi Android. Le implementazioni del dispositivo devono supportare la famiglia del tema "materiale" e non devono alterare nessuno degli attributi tematici materiali o le loro attività esposte alle applicazioni [ risorse, 35 ].

Android include anche una famiglia a tema "dispositivo predefinito" come insieme di stili definiti per gli sviluppatori di applicazioni da utilizzare se vogliono abbinare l'aspetto del tema del dispositivo come definito dall'implementatore del dispositivo. Le implementazioni del dispositivo possono modificare gli attributi del tema predefinito del dispositivo esposti alle applicazioni [ Risorse, 34 ].

Android supporta un tema variante con barre di sistema traslucide, che consente agli sviluppatori di applicazioni di riempire l'area dietro lo stato e la barra di navigazione con il loro contenuto dell'app. Per abilitare un'esperienza di sviluppatore coerente in questa configurazione, è importante che lo stile dell'icona della barra di stato sia mantenuto tra diverse implementazioni del dispositivo. Pertanto, le implementazioni del dispositivo Android devono utilizzare il bianco per le icone di stato del sistema (come la potenza del segnale e il livello della batteria) e le notifiche emesse dal sistema, a meno che l'icona non indicasse uno stato problematico o un'app richieda una barra di stato della luce utilizzando la flag System_Ui_Flag_light_Status_Bar. Quando un'app richiede una barra di stato della luce, le implementazioni del dispositivo Android devono modificare il colore delle icone di stato del sistema in nero [ Risorse, 34 ].

3.8.7. Sfondi animati

Android definisce un tipo di componente e un corrispondente API e ciclo di vita che consente alle applicazioni di esporre uno o più "sfondi vivi" all'utente finale [ Risorse, 36 ]. Gli sfondi dal vivo sono animazioni, motivi o immagini simili con capacità di input limitate che vengono visualizzate come sfondo, dietro altre applicazioni.

L'hardware è considerato in grado di eseguire sfondi vivi in ​​modo affidabile se può eseguire tutti gli sfondi vivi, senza limiti alla funzionalità, a un frame rate ragionevole senza effetti avversi su altre applicazioni. Se le limitazioni nell'hardware causano crash di sfondi e/o applicazioni, malfunzionamento, consumano CPU eccessiva o batteria o eseguono una velocità di frame inaccettabilmente bassa, l'hardware è considerato incapace di eseguire sfondo in tempo reale. Ad esempio, alcuni sfondi in diretta possono utilizzare un contesto OpenGL 2.0 o 3.x per rendere i loro contenuti. Lo sfondo in diretta non si eseguerà in modo affidabile su hardware che non supporta più contesti OpenGL perché l'uso del sfondo in diretta di un contesto OpenGL può essere in conflitto con altre applicazioni che utilizzano anche un contesto OpenGL.

Implementazioni del dispositivo in grado di eseguire sfondi in diretta in modo affidabile come descritto sopra, dovrebbero implementare sfondi in diretta e, se implementati, devono segnalare il flag di funzionalità della piattaforma Android.Software.live_wallpaper.

3.8.8. Commutazione dell'attività

Il codice sorgente Android upstream include la schermata Panoramica [ Risorse, 37 ], un'interfaccia utente a livello di sistema per la commutazione delle attività e la visualizzazione di attività e attività di recente accessibile utilizzando un'immagine in miniatura dello stato grafico dell'applicazione nel momento in cui l'utente ha lasciato ultimo l'applicazione. Le implementazioni del dispositivo, incluso la chiave di navigazione delle funzioni di rece, come dettagliato nella Sezione 7.2.3 , possono modificare l'interfaccia ma devono soddisfare i seguenti requisiti:

• Deve visualizzare i recenti affiliati come gruppo che si muove insieme.
• Deve supportare almeno fino a 6 attività visualizzate.
• Dovrebbe almeno visualizzare il titolo di 4 attività alla volta.
• Dovrebbe visualizzare il colore di evidenziazione, l'icona, il titolo dello schermo in recenti.
• Deve implementare il comportamento di blocco dello schermo [ risorse, 38 ] e fornire all'utente un menu Impostazioni per attivare la funzione.
• Dovrebbe visualizzare una convenienza di chiusura ("X") ma può ritardare fino a quando l'utente non interagisce con gli schermi.

Le implementazioni del dispositivo sono fortemente consigliate di utilizzare l'interfaccia utente Android a monte (o un'interfaccia basata su miniatura simile) per la schermata Panoramica.

3.8.9. Gestione delle input

Android include il supporto per la gestione delle input e il supporto per i redattori di metodi di input di terze parti [ risorse, 39 ]. Le implementazioni del dispositivo che consentono agli utenti di utilizzare metodi di input di terze parti sul dispositivo devono dichiarare la funzionalità della piattaforma Android.Software.input_Methods e supportare API IME come definito nella documentazione SDK Android.

Le implementazioni del dispositivo che dichiarano la funzione Android.Software.input_Methods devono fornire un meccanismo accessibile dall'utente per aggiungere e configurare i metodi di input di terze parti. Le implementazioni del dispositivo devono visualizzare l'interfaccia Impostazioni in risposta all'intento Android.settings.input_method_settings.

3.8.10. Controllo multimediale della schermata di blocco

L'API client Remote Control è deprecata da Android 5.0 a favore del modello di notifica multimediale che consente alle applicazioni multimediali di integrarsi con i controlli di riproduzione visualizzati sulla schermata di blocco [ Risorse, 40 ] come notifiche di schermata di blocco. Le implementazioni del dispositivo devono rendere correttamente il modello di notifica multimediale come parte delle notifiche della schermata di blocco descritte nella Sezione 3.8.3.

3.8.11. Sogni

Android include supporto per screensaver interattivi chiamati Dreams [ Risorse, 41 ]. Dreams consente agli utenti di interagire con le applicazioni quando un dispositivo connesso a una fonte di alimentazione è inattivo o attratto in un dock da scrivania. I dispositivi di orologi Android possono implementare i sogni, ma altri tipi di implementazioni del dispositivo dovrebbero includere il supporto per i sogni e fornire un'opzione Impostazioni per gli utenti di configurare i sogni in risposta all'intento Android.settings.dream_settings.

3.8.12. Posizione

Quando un dispositivo ha un sensore hardware (ad es. GPS) in grado di fornire le coordinate di posizione, le modalità di posizione devono essere visualizzate nel menu di posizione all'interno delle impostazioni [ risorse, 42 ].

3.8.13. Unicode e carattere

Android include il supporto per i personaggi delle emoji a colori. Quando le implementazioni di dispositivi Android includono un IME, i dispositivi dovrebbero fornire un metodo di input all'utente per i caratteri Emoji definiti in Unicode 6.1 [ Risorse, 43 ]. Tutti i dispositivi devono essere in grado di rendere questi personaggi emoji nel glifo a colori.

Android include il supporto per il carattere roboto 2 con pesi diversi-san-serif-sottile, sans-serif-lughip, sans-serif-medio, sans-serif-n-n-n-n-n-n-n-n-n-n-n-n-n-n-n-black, sans-serif condensato, sans-serif-light-light- Devono essere tutti inclusi per le lingue disponibili sul dispositivo e per la copertura piena di Unicode 7.0 di latino, greco e cirillico, tra cui le gamme latine estese A, B, C e D e tutti glifi nel blocco dei simboli di valuta di Unicode 7.0.

3.9. Amministrazione del dispositivo

Android include funzionalità che consentono alle applicazioni consapevoli della sicurezza di eseguire funzioni di amministrazione dei dispositivi a livello di sistema, come l'applicazione di politiche di password o l'esecuzione di una pulizia remota, attraverso l'API di amministrazione dei dispositivi Android [ risorse, 44 ]. Le implementazioni del dispositivo devono fornire un'implementazione della classe DevicePolicyManager [ risorse, 45 ]. Le implementazioni del dispositivo che includono il supporto per le schermate di blocco basate su Pin (Numeric) o Password (Alphanumeric) devono supportare l'intera gamma di politiche di amministrazione dei dispositivi definiti nella documentazione SDK Android [ Risorse, 44 ] e riportare la caratteristica della piattaforma Android.Software.Device_Admin.

3.9.1 Provuzione dei dispositivi

3.9.1.1 Provuzione del proprietario del dispositivo

Se un'implementazione del dispositivo dichiara la funzione Android.Software.device_admin, il flusso di configurazione fuori dalla scatola deve consentire di iscrivere un'applicazione DPC (Dispositive Policy Polict) come app per il proprietario del dispositivo [ risorse, 46 ]. Le implementazioni del dispositivo possono avere un'applicazione preinstallata che esegue le funzioni di amministrazione del dispositivo, ma questa applicazione non deve essere impostata come app per il proprietario del dispositivo senza consenso esplicito o azione da parte dell'utente o dell'amministratore del dispositivo.

Il processo di provisioning del proprietario del dispositivo (il flusso avviato da Android.App.Action.Provision_Managed_Device [ risorse, 47 ]) l'esperienza dell'utente deve allinearsi con l'implementazione AOSP

Se l'implementazione del dispositivo riporta Android.hardware.nfc, deve avere NFC abilitato, anche durante il flusso di configurazione fuori dalla scatola, al fine di consentire il provisioning NFC dei proprietari di dispositivi [ risorse, 48 ].

3.9.1.2 Produzione del profilo gestito

Se un'implementazione del dispositivo dichiara Android.Software.Managed_users, deve essere possibile iscrivere un'applicazione DPC (Dispositive Policy Controller) come proprietario di un nuovo profilo gestito [ Risorse, 49 ]

Il processo di provisioning del profilo gestito (il flusso avviato da Android.app.action.provision_managed_profile [ risorse, 50 ]) l'esperienza dell'utente deve allinearsi con l'implementazione AOSP

3.9.2 Supporto del profilo gestito

I dispositivi capaci di profilo gestito sono quei dispositivi che:

• Dichiarare Android.Software.device_admin (vedere la sezione 3.9 Amministrazione dei dispositivi)
• Non sono dispositivi a bassa RAM (vedere la Sezione 7.6.1
• Allocare l'archiviazione interna (non rimovibile) come archiviazione condivisa (vedere la Sezione 7.6.2 )

I dispositivi capaci di profilo gestito devono:

• Dichiarare il flag di funzionalità della piattaforma Android.Software.Managed_users.
• Supporto profili gestiti tramite le API Android.App.admin.devicepolicymanager
• Consenti di creare uno e un solo profilo gestito [ risorse, 50 ]
• Utilizzare un badge Icon (simile al badge di lavoro a monte Aosp) per rappresentare le applicazioni e i widget gestiti e altri elementi dell'interfaccia utente badge come recenti e notifiche
• Visualizza un'icona di notifica (simile al badge di lavoro a monte Aosp) per indicare quando l'utente è all'interno di un'applicazione del profilo gestito
• Visualizza un brindisi che indica che l'utente è nel profilo gestito se e quando il dispositivo si sveglia (action_user_present) e l'applicazione in primo piano è all'interno del profilo gestito
• Laddove esiste un profilo gestito, mostra una convenienza visiva nell'intento "scelta" per consentire all'utente di inoltrare l'intento dal profilo gestito all'utente primario o viceversa, se abilitato dal controller dei criteri del dispositivo
• Laddove esiste un profilo gestito, esponi le seguenti convenzioni utente sia per l'utente principale che per il profilo gestito:
  • Contabilità separata per batteria, posizione, dati mobili e utilizzo di archiviazione per l'utente primario e il profilo gestito.
  • Gestione indipendente delle applicazioni VPN installate all'interno dell'utente primario o del profilo gestito.
  • Gestione indipendente delle applicazioni installate all'interno dell'utente principale o del profilo gestito.
  • Gestione indipendente degli account all'interno dell'utente primario o del profilo gestito.
• Assicurarsi che il dialer predefinito possa cercare le informazioni del chiamante dal profilo gestito (se esiste) insieme a quelli del profilo primario, se il controller del critero del dispositivo lo consente.
• Deve garantire che soddisfi tutti i requisiti di sicurezza applicabili per un dispositivo con più utenti abilitati (vedere la sezione 9.5 ), anche se il profilo gestito non viene conteggiato come un altro utente oltre all'utente primario.

3.10. Accessibilità

Android fornisce un livello di accessibilità che aiuta gli utenti con disabilità per navigare più facilmente i propri dispositivi. Inoltre, Android fornisce API della piattaforma che consentono alle implementazioni del servizio di accessibilità di ricevere callback per eventi utente e di sistema e generare meccanismi di feedback alternativi, come la navigazione text-to-speech, tattile e navigazione trackball/D-pad [ risorse, 51 ].

Le implementazioni del dispositivo includono i seguenti requisiti:

• Le implementazioni automobilistiche Android dovrebbero fornire un'implementazione del framework di accessibilità Android coerente con l'implementazione di Android predefinita.
• Le implementazioni dei dispositivi (Android Automotive escluse) devono fornire un'implementazione del framework di accessibilità Android coerente con l'implementazione di Android predefinita.
• Le implementazioni dei dispositivi (Android Automotive escluse) devono supportare le implementazioni del servizio di accessibilità di terze parti tramite Android.AccessibilityService API [ Risorse, 52 ]
• Le implementazioni del dispositivo (Android Automotive escluse) devono generare accessibilità e consegnare questi eventi a tutte le accessibilità registrate Implementazioni in modo coerente con l'implementazione di Android predefinita
• Le implementazioni del dispositivo (dispositivi di orologi Android Automotive e Android senza esclusi output audio), devono fornire un meccanismo ad accesso utente per abilitare e disabilitare i servizi di accessibilità e devono visualizzare questa interfaccia in risposta a Android.Provider.settings.Action_Accessibility_Settings IntenT.

Inoltre, le implementazioni del dispositivo dovrebbero fornire un'implementazione di un servizio di accessibilità sul dispositivo e fornire un meccanismo per gli utenti per consentire il servizio di accessibilità durante la configurazione del dispositivo. Un'implementazione open source di un servizio di accessibilità è disponibile da The Eyes Free Project [ Risorse, 53 ].

3.11. Text-to-spealch

Android include API che consentono alle applicazioni di utilizzare i servizi TEX-to-Speech (TTS) e consente ai fornitori di servizi di fornire implementazioni dei servizi TTS [ risorse, 54 ]. Implementazioni del dispositivo che riportano la funzione Android.hardware.Audio.Output deve soddisfare questi requisiti relativi al framework Android TTS.

Implementazioni automobilistiche Android:

• Deve supportare le API Framework Android TTS.
• Può supportare l'installazione di motori TTS di terze parti. Se supportati, i partner devono fornire un'interfaccia accessibile dall'utente che consente all'utente di selezionare un motore TTS per l'uso a livello di sistema.

Tutte le altre implementazioni del dispositivo:

• Deve supportare le API Framework TTS Android e deve includere un motore TTS a supporto delle lingue disponibili sul dispositivo. Si noti che il software open source Android a monte include un'implementazione del motore TTS completo.
• Deve supportare l'installazione di motori TTS di terze parti
• Deve fornire un'interfaccia accessibile dall'utente che consente agli utenti di selezionare un motore TTS da utilizzare a livello di sistema

3.12. Framework di input TV

Il framework di input televisivi Android (TIF) semplifica la consegna di contenuti dal vivo ai dispositivi televisivi Android. TIF fornisce un'API standard per creare moduli di input che controllano i dispositivi televisivi Android. Le implementazioni di dispositivi televisivi Android devono supportare il framework di input TV [ risorse, 55 ].

Implementazioni del dispositivo che supportano TIF devono dichiarare la funzionalità della piattaforma Android.Software.live_tv.

3.12.1. App TV

Qualsiasi implementazione del dispositivo che dichiari il supporto per la TV in diretta deve avere un'applicazione TV installata (app TV). Il progetto open source Android fornisce un'implementazione dell'app TV.

L'app TV predefinita deve fornire l'accesso ai canali da ingressi installati e input di terze parti. Si noti che gli ingressi installati comprendono tutti gli ingressi forniti per impostazione predefinita, siano essi basati su TIF o meno.

L'app TV deve fornire strutture per installare e utilizzare i canali TV [ risorse, 56 ] e soddisfare i seguenti requisiti:

• Le implementazioni del dispositivo devono consentire l'installazione e la gestione degli input basati su TIF di terze parti (input di terze parti) [ Risorse, 57 ].
• Le implementazioni del dispositivo possono fornire una separazione visiva tra ingressi basati su TIF preinstallati (input installati) [ risorse, 58 ] e input di terze parti.
• Le implementazioni del dispositivo non devono visualizzare gli ingressi di terze parti più di una singola azione di navigazione dall'app TV (cioè espandere un elenco di input di terze parti dall'app TV).

3.12.1.1. Guida al programma elettronico

Le implementazioni di dispositivi televisivi Android devono mostrare un overlay informativo e interattivo, che deve includere una guida al programma elettronico (EPG) generato dai valori nei campi TVContract.programs [ risorse, 59 ]. L'EPG deve soddisfare i seguenti requisiti:

• L'EPG deve visualizzare le informazioni da tutti gli ingressi installati e gli ingressi di terze parti.
• L'EPG può fornire una separazione visiva tra gli ingressi installati e gli input di terze parti.
• L'EPG è fortemente consigliato per visualizzare ingressi installati e input di terze parti con uguale importanza. L'EPG non deve visualizzare gli ingressi di terze parti più di una singola azione di navigazione lontano dagli ingressi installati sull'EPG.
• Sulla modifica del canale, le implementazioni del dispositivo devono visualizzare i dati EPG per il programma attualmente riprodotto.

3.12.1.2. Navigazione

I dispositivi di input del dispositivo televisivo Android (cioè controllo remoto, applicazione del telecomando o controller di gioco) devono consentire la navigazione in tutte le sezioni attuabili dello schermo tramite D-Pad. D-Pad su e giù deve essere utilizzato per cambiare i canali TV in diretta quando non esiste una sezione attuabile sullo schermo.

L'app TV dovrebbe passare eventi chiave agli input HDMI tramite CEC.

3.12.1.3. Collegamento dell'app di input TV

Le implementazioni di dispositivi televisivi Android devono supportare il collegamento dell'app di input TV, che consente a tutti gli input di fornire collegamenti di attività dall'attività corrente a un'altra attività (cioè un collegamento dalla programmazione live a contenuti correlati) [ Risorse, 60 ]. L'app TV deve mostrare l'app di input TV quando viene fornita.

4. Compatibilità dell'imballaggio dell'applicazione

Le implementazioni del dispositivo devono installare ed eseguire file ".APK" Android, generati dallo strumento "AAPT" incluso nell'SDK Android ufficiale [ risorse, 61 ].

Le implementazioni dei dispositivi non devono estendere né il .Apk [ Risorse, 62 ], Android Manifest [ Risorse, 49 ], Dalvik Bytecode [ Resources, 23 ] o Renderscript Bytecode Formati in modo tale da impedire a tali file di installare e funzionare correttamente su Altri dispositivi compatibili.

5. Compatibilità multimediale

5.1. Codec multimediali

Le implementazioni del dispositivo devono supportare i formati di media di base specificati nella documentazione SDK Android [ Risorse, 64 ] tranne se esplicitamente consentite in questo documento. In particolare, le implementazioni del dispositivo devono supportare i formati multimediali, gli encoder, i decodificatori, i tipi di file e i formati di contenitori definiti nelle tabelle seguenti e riportate tramite MediaCodeClist [ Risorse, 65 ]. Le implementazioni del dispositivo devono inoltre essere in grado di decodificare tutti i profili riportati nel suo profilo CAMCORDER [ Risorse, 66 ] e devono essere in grado di decodificare tutti i formati che può codificare. Tutti questi codec sono forniti come implementazioni software nell'implementazione Android preferita dal progetto open source Android.

Si prega di notare che né Google né l'Alleanza Open Handset rendono alcuna rappresentanza che questi codec sono liberi da brevetti di terze parti. Coloro che intendono utilizzare questo codice sorgente in prodotti hardware o software sono consigliati che le implementazioni di questo codice, anche nel software open source o shareware, potrebbero richiedere licenze di brevetto dai detentori di brevetti pertinenti.

5.1.1. Codec audio

Formato/codec	Codificatore	Decodificatore	Dettagli	Tipi di file supportati/formati di container
Profilo AAC MPEG-4 (AAC LC)	Richiesto 1	NECESSARIO	Supporto per contenuto mono/stereo/5.0/5.1 2 con velocità di campionamento standard da 8 a 48 kHz.	3GPP (.3GP) MPEG-4 (.mp4, .m4a) ADTS RAW AAC (.AAC, decodifica in Android 3.1+, codifica in Android 4.0+, ADI non supportato) MPEG-TS (.TS, NON SECHEABLE, ANDROID 3.0+)
MPEG-4 HE Profilo AAC (AAC+)	Richiesto 1 (Android 4.1+)	NECESSARIO	Supporto per contenuto mono/stereo/5.0/5.1 2 con velocità di campionamento standard da 16 a 48 kHz.
MPEG-4 he AACV2 Profilo (AAC+Enhanced AAC+)		NECESSARIO	Supporto per contenuto mono/stereo/5.0/5.1 2 con velocità di campionamento standard da 16 a 48 kHz.
AAC ELD (AAC a basso ritardo a basso ritardo)	Richiesto 1 (Android 4.1+)	NECESSARIO (Android 4.1+)	Supporto per contenuti mono/stereo con velocità di campionamento standard da 16 a 48 kHz.
AMR-NB	Richiesto 3	Richiesto 3	4,75 a 12,2 kbps campionato @ 8 kHz	3GPP (.3GP)
AMR-WB	Richiesto 3	Richiesto 3	9 tassi da 6,60 kbit/s a 23,85 kbit/s campionati a 16 kHz
FLAC		NECESSARIO (Android 3.1+)	Mono/stereo (nessun multicanale). Tariffe di campionamento fino a 48 kHz (ma fino a 44,1 kHz sono raccomandati su dispositivi con output a 44,1 kHz, poiché il downsampler da 48 a 44,1 kHz non include un filtro passa-basso). 16 bit raccomandato; Nessun dither ha applicato a 24 bit.	Solo flac (.flac)
MP3		NECESSARIO	Mono/stereo 8-320kbps costante (CBR) o bitrate variabile (VBR)	Mp3 (.mp3)
MIDI		NECESSARIO	MIDI Tipo 0 e 1. DLS versione 1 e 2. XMF e mobile XMF. Supporto per formati di suoneria RTTTL/RTX, OTA e IMELODY	Tipo 0 e 1 (.mid, .xmf, .mxmf) Rtttl/rtx (.rtttl, .rtx) Ota (.ota) imelody (.imy)
Vorbis		NECESSARIO		Ogg (.ogg) Matroska (.mkv, Android 4.0+)
PCM/Wave	Richiesto 4 (Android 4.1+)	NECESSARIO	PCM lineare a 16 bit (tariffe fino al limite dell'hardware). I dispositivi devono supportare le tariffe di campionamento per la registrazione PCM grezza a frequenze 8000, 11025, 16000 e 44100 Hz.	Wave (.Wav)
Opus		NECESSARIO (Android 5.0+)		Matroska (.Mkv)

1 richiesto per le implementazioni del dispositivo che definiscono Android.hardware.microfono ma facoltativo per le implementazioni di dispositivi di orologi Android.

2 È richiesto solo un recesso del contenuto 5.0/5.1; La registrazione o il rendering di più di 2 canali è facoltativo.

3 richiesto per le implementazioni di dispositivi portatile Android.

4 richiesti per le implementazioni del dispositivo che definiscono Android.hardware.microfono, comprese le implementazioni di dispositivi di orologi Android.

5.1.2. Codec di immagine

Formato/codec	Codificatore	Decodificatore	Dettagli	Supported File Types/Container Formats
JPEG	NECESSARIO	NECESSARIO	Base+progressive	JPEG (.jpg)
GIF		NECESSARIO		GIF (.gif)
PNG	NECESSARIO	NECESSARIO		PNG (.png)
BMP		NECESSARIO		BMP (.bmp)
WebP	NECESSARIO	NECESSARIO		WebP (.webp)

5.1.3. Video Codecs

Format/Codec	Codificatore	Decoder	Dettagli	Supported File Types/ Container Formats
H.263	REQUIRED 1	REQUIRED 2		3GPP (.3gp) MPEG-4 (.mp4)
H.264 AVC	REQUIRED 2	REQUIRED 2	See section 5.2 and 5.3 for details	3GPP (.3gp) MPEG-4 (.mp4) MPEG-2 TS (.ts, AAC audio only, not seekable, Android 3.0+)
H.265 HEVC		REQUIRED 5	See section 5.3 for details	MPEG-4 (.mp4)
MPEG-2		STRONGLY RECOMMENDED 6	Profilo principale	MPEG2-TS
MPEG-4 SP		REQUIRED 2		3GPP (.3gp)
VP8 3	REQUIRED 2 (Android 4.3+)	REQUIRED 2 (Android 2.3.3+)	See section 5.2 and 5.3 for details	WebM (.webm) [ Resources, 67 Matroska (.mkv, Android 4.0+) 4
VP9		REQUIRED 2 (Android 4.4+)	See section 5.3 for details	WebM (.webm) [ Resources, 67 ] Matroska (.mkv, Android 4.0+) 4

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

2 Required for device implementations except Android Watch devices.

3 For acceptable quality of web video streaming and video-conference services, device implementations SHOULD use a hardware VP8 codec that meets the requirements in [ Resources, 68 ].

4 Device implementations SHOULD support writing Matroska WebM files.

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

6 Applies only to Android Television device implementations.

5.2. Video Encoding

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

Android device implementations with H.264 codec support, MUST support Baseline Profile Level 3 and the following SD (Standard Definition) video encoding profiles and SHOULD support Main Profile Level 4 and the following HD (High Definition) video encoding profiles. Android Television devices are STRONGLY RECOMMENDED to encode HD 1080p video at 30 fps.

	SD (Low quality)	SD (High quality)	HD 720p 1	HD 1080p 1
Risoluzione video	320 x 240 px	720 x 480 px	1280 x 720 px	1920 x 1080 px
Video frame rate	20 fps	30 fps	30 fps	30 fps
Bitrate video	384 Kbps	2 Mbps	4 Mbps	10 Mbps

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

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

	SD (Low quality)	SD (High quality)	HD 720p 1	HD 1080p 1
Risoluzione video	320 x 180 px	640 x 360 px	1280 x 720 px	1920 x 1080 px
Video frame rate	30 fps	30 fps	30 fps	30 fps
Bitrate video	800 Kbps	2 Mbps	4 Mbps	10 Mbps

1 When supported by hardware.

5.3. Video Decoding

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

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

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

Android device implementations with H.264 decoders, MUST support Main Profile Level 3.1 and the following SD video decoding profiles and SHOULD support the HD decoding profiles. Android Television devices MUST support High Profile Level 4.2 and the HD 1080p decoding profile.

	SD (Low quality)	SD (High quality)	HD 720p 1	HD 1080p 1
Risoluzione video	320 x 240 px	720 x 480 px	1280 x 720 px	1920 x 1080 px
Video frame rate	30 fps	30 fps	60 fps	30 fps / 60 fps 2
Bitrate video	800 Kbps	2 Mbps	8 Mbps	20 Mbps

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

2 REQUIRED for Android Television device implementations.

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

	SD (Low quality)	SD (High quality)	HD 720p 1	HD 1080p 1
Risoluzione video	320 x 180 px	640 x 360 px	1280 x 720 px	1920 x 1080 px
Video frame rate	30 fps	30 fps	30 fps / 60 fps 2	30 / 60 fps 2
Bitrate video	800 Kbps	2 Mbps	8 Mbps	20 Mbps

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

2 REQUIRED for Android Television device implementations.

Android device implementations, when supporting VP9 codec as described in section 5.1.3 , MUST support the following SD video decoding profiles and SHOULD support the HD decoding profiles. Android Television devices are STRONGLY RECOMMENDED to support the HD 1080p decoding profile and SHOULD support the UHD decoding profile. When the UHD video decoding profile is supported, it MUST support 8-bit color depth and SHOULD support VP9 Profile 2 (10-bit).

	SD (Low quality)	SD (High quality)	HD 720p 1	HD 1080p 2	UHD 2
Risoluzione video	320 x 180 px	640 x 360 px	1280 x 720 px	1920 x 1080 px	3840 x 2160 px
Video frame rate	30 fps	30 fps	30 fps	60 fps	60 fps
Bitrate video	600 Kbps	1.6 Mbps	4 Mbps	5 Mbps	20 Mbps

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

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

Android device implementations, when supporting H.265 codec as described in section 5.1.3 , MUST support the Main Profile Level 3 Main tier and the following SD video decoding profiles and SHOULD support the HD decoding profiles. Android Television devices are STRONGLY RECOMMENDED to support the UHD decoding profile and the HD 1080p decoding profile. If the HD 1080p decoding profile is supported, it MUST support the Main Profile Level 4.1 Main tier. If UHD decoding is supported, then it MUST support Main10 Level 5 Main Tier profile.

	SD (Low quality)	SD (High quality)	HD 720p 1	HD 1080p 2	UHD 2
Risoluzione video	352 x 288 px	640 x 360 px	1280 x 720 px	1920 x 1080 px	3840 x 2160 px
Video frame rate	30 fps	30 fps	30 fps	60 fps 2	60 fps
Bitrate video	600 Kbps	1.6 Mbps	4 Mbps	10 Mbps	20 Mbps

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

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

5.4. Registrazione audio

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

5.4.1. Raw Audio Capture

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

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

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

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

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

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

5.4.2. Capture for Voice Recognition

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

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

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

5.4.3. Capture for Rerouting of Playback

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

• STREAM_RING
• STREAM_ALARM
• STREAM_NOTIFICATION

5.5. Riproduzione audio

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

5.5.1. Raw Audio Playback

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

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

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

• Sampling rates : 24000, 48000

5.5.2. Audio Effects

Android provides an API for audio effects for device implementations [ Resources, 69 ]. Device implementations that declare the feature android.hardware.audio.output:

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

5.5.3. Audio Output Volume

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

5.6. Audio Latency

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

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

• output latency . The interval between when an application writes a frame of PCM-coded data and when the corresponding sound can be heard by an external listener or observed by a transducer.
• cold output latency . The output latency for the first frame, when the audio output system has been idle and powered down prior to the request.
• continuous output latency . The output latency for subsequent frames, after the device is playing audio.
• input latency . The interval between when an external sound is presented to the device and when an application reads the corresponding frame of PCM-coded data.
• cold input latency . The sum of lost input time and the input latency for the first frame, when the audio input system has been idle and powered down prior to the request.
• continuous input latency . The input latency for subsequent frames, while the device is capturing audio.
• cold output jitter . The variance among separate measurements of cold output latency values.
• cold input jitter . The variance among separate measurements of cold input latency values.
• continuous round-trip latency . The sum of continuous input latency plus continuous output latency plus one buffer period. The buffer period term allows processing time for the app and for the app to mitigate phase difference between input and output streams.
• OpenSL ES PCM buffer queue API . The set of PCM-related OpenSL ES APIs within Android NDK; see NDK_root/docs/opensles/index.html.

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

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

If a device implementation meets the requirements of this section after any initial calibration when using the OpenSL ES PCM buffer queue API, for continuous output latency and cold output latency over at least one supported audio output device, it is STRONGLY RECOMMENDED to report support for low-latency audio, by reporting the feature android.hardware.audio.low_latency via the android.content.pm.PackageManager class [ Resources, 70 ]. Conversely, if the device implementation does not meet these requirements it MUST NOT report support for low-latency audio.

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

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

5.7. Network Protocols

Devices MUST support the media network protocols for audio and video playback as specified in the Android SDK documentation [ Resources, 64 ]. Specifically, devices MUST support the following media network protocols:

• RTSP (RTP, SDP)
• HTTP(S) progressive streaming
• HTTP(S) Live Streaming draft protocol, Version 3 [ Resources, 71 ]

5.8. Secure Media

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

5.9. Interfaccia digitale per strumenti musicali (MIDI)

If a device implementation supports the inter-app MIDI software transport (virtual MIDI devices), and it supports MIDI over all of the following MIDI-capable hardware transports for which it provides generic non-MIDI connectivity, it is STRONGLY RECOMMENDED to report support for feature android.software.midi via the android.content.pm.PackageManager class [ Resources, 70 ].

The MIDI-capable hardware transports are:

• USB host mode (section 7.7 USB)
• USB peripheral mode (section 7.7 USB)

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

MIDI over Bluetooth LE acting in central role (section 7.4.3 Bluetooth) is in trial use status. A device implementation that reports feature android.software.midi, and which provides generic non-MIDI connectivity over Bluetooth LE, SHOULD support MIDI over Bluetooth LE.

5.10. Professional Audio

If a device implementation meets all of the following requirements, it is STRONGLY RECOMMENDED to report support for feature android.hardware.audio.pro via the android.content.pm.PackageManager class [ Resources, 70 ].

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

6. Developer Tools and Options Compatibility

6.1. Strumenti di sviluppo

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

• Android Debug Bridge (adb) [ Resources, 72 ]

Device implementations MUST support all adb functions as documented in the Android SDK including dumpsys [ Resources, 73 ]. The device-side adb daemon MUST be inactive by default and there MUST be a user-accessible mechanism to turn on the Android Debug Bridge. If a device implementation omits USB peripheral mode, it MUST implement the Android Debug Bridge via local-area network (such as Ethernet or 802.11).

Android includes support for secure adb. Secure adb enables adb on known authenticated hosts. Device implementations MUST support secure adb.

• Dalvik Debug Monitor Service (ddms) [ Resources, 74 ]

Device implementations MUST support all ddms features as documented in the Android SDK. As ddms uses adb, support for ddms SHOULD be inactive by default, but MUST be supported whenever the user has activated the Android Debug Bridge, as above.

• Monkey [ Resources, 75 ]

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

• SysTrace [ Resources, 76 ]

Device implementations MUST support systrace tool as documented in the Android SDK. Systrace must be inactive by default, and there MUST be a user-accessible mechanism to turn on Systrace.

Most Linux-based systems and Apple Macintosh systems recognize Android devices using the standard Android SDK tools, without additional support; however Microsoft Windows systems typically require a driver for new Android devices. (For instance, new vendor IDs and sometimes new device IDs require custom USB drivers for Windows systems.) If a device implementation is unrecognized by the adb tool as provided in the standard Android SDK, device implementers MUST provide Windows drivers allowing developers to connect to the device using the adb protocol. These drivers MUST be provided for Windows XP, Windows Vista, Windows 7, Windows 8 and Windows 10 in both 32-bit and 64-bit versions.

6.2. Opzioni sviluppatore

Android includes support for developers to configure application development-related settings. Device implementations MUST honor the android.settings.APPLICATION_DEVELOPMENT_SETTINGS intent to show application development-related settings [ Resources, 77 ]. The upstream Android implementation hides the Developer Options menu by default and enables users to launch Developer Options after pressing seven (7) times on the Settings > About Device > Build Number menu item. Device implementations MUST provide a consistent experience for Developer Options. Specifically, device implementations MUST hide Developer Options by default and MUST provide a mechanism to enable Developer Options that is consistent with the upstream Android implementation.

7. Hardware Compatibility

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

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

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

Device implementations MUST consistently report accurate hardware configuration information via the getSystemAvailableFeatures() and hasSystemFeature(String) methods on the android.content.pm.PackageManager class for the same build fingerprint. [ Resources, 70 ]

7.1. Display and Graphics

Android includes facilities that automatically adjust application assets and UI layouts appropriately for the device, to ensure that third-party applications run well on a variety of hardware configurations [ Resources, 78 ]. Devices MUST properly implement these APIs and behaviors, as detailed in this section.

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

• physical diagonal size . The distance in inches between two opposing corners of the illuminated portion of the display.
• dots per inch (dpi) . The number of pixels encompassed by a linear horizontal or vertical span of 1”. Where dpi values are listed, both horizontal and vertical dpi must fall within the range.
• proporzioni . The ratio of the pixels of the longer dimension to the shorter dimension of the screen. For example, a display of 480x854 pixels would be 854/480 = 1.779, or roughly “16:9”.
• density-independent pixel (dp) The virtual pixel unit normalized to a 160 dpi screen, calculated as: pixels = dps * (density/160).

7.1.1. Screen Configuration

7.1.1.1. Dimensione dello schermo

The Android UI framework supports a variety of different screen sizes, and allows applications to query the device screen size (aka “screen layout") via android.content.res.Configuration.screenLayout with the SCREENLAYOUT_SIZE_MASK. Device implementations MUST report the correct screen size as defined in the Android SDK documentation [ Resources, 78 ] and determined by the upstream Android platform. Specifically, device implementations MUST report the correct screen size according to the following logical density-independent pixel (dp) screen dimensions.

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

Inoltre,

• Android Watch devices MUST have a screen with the physical diagonal size in the range from 1.1 to 2.5 inches.
• Other types of Android device implementations, with a physically integrated screen, MUST have a screen at least 2.5 inches in physical diagonal size.

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

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

7.1.1.2. Proporzioni dello schermo

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

7.1.1.3. Screen Density

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

• 120 dpi (ldpi)
• 160 dpi (mdpi)
• 213 dpi (tvdpi)
• 240 dpi (hdpi)
• 280 dpi (280dpi)
• 320 dpi (xhdpi)
• 360 dpi (360dpi)
• 400 dpi (400dpi)
• 420 dpi (420dpi)
• 480 dpi (xxhdpi)
• 560 dpi (560dpi)
• 640 dpi (xxxhdpi)

Device implementations SHOULD define the standard Android framework density that is numerically closest to the physical density of the screen, unless that logical density pushes the reported screen size below the minimum supported. If the standard Android framework density that is numerically closest to the physical density results in a screen size that is smaller than the smallest supported compatible screen size (320 dp width), device implementations SHOULD report the next lowest standard Android framework density.

7.1.2. Display Metrics

Device implementations MUST report correct values for all display metrics defined in android.util.DisplayMetrics [ Resources, 79 ] and MUST report the same values regardless of whether the embedded or external screen is used as the default display.

7.1.3. Orientamento schermo

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

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

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

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

7.1.4. 2D and 3D Graphics Acceleration

Device implementations MUST support both OpenGL ES 1.0 and 2.0, as embodied and detailed in the Android SDK documentations. Device implementations SHOULD support OpenGL ES 3.0 or 3.1 on devices capable of supporting it. Device implementations MUST also support Android RenderScript, as detailed in the Android SDK documentation [ Resources, 80 ].

Device implementations MUST also correctly identify themselves as supporting OpenGL ES 1.0, OpenGL ES 2.0, OpenGL ES 3.0 or OpenGL 3.1. Questo è:

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

In addition to OpenGL ES 3.1, Android provides an extension pack with Java interfaces [ Resources, 81 ] and native support for advanced graphics functionality such as tessellation and the ASTC texture compression format. Android device implementations MAY support this extension pack, and—only if fully implemented—MUST identify the support through the android.hardware.opengles.aep feature flag.

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

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

Android includes a mechanism for applications to declare that they want to enable hardware acceleration for 2D graphics at the Application, Activity, Window, or View level through the use of a manifest tag android:hardwareAccelerated or direct API calls [ Resources, 82 ].

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, 82 ].

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

Android includes support for EGL_ANDROID_RECORDABLE, an EGLConfig attribute that indicates whether the EGLConfig supports rendering to an ANativeWindow that records images to a video. Device implementations MUST support EGL_ANDROID_RECORDABLE extension [ Resources, 83 ].

7.1.5. Legacy Application Compatibility Mode

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

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

7.1.6. Screen Technology

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

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

7.1.7. Secondary Displays

Android includes support for secondary display to enable media sharing capabilities and developer APIs for accessing external displays. If a device supports an external display either via a wired, wireless, or an embedded additional display connection then the device implementation MUST implement the display manager API as described in the Android SDK documentation [ Resources, 84 ].

7.2. Input Devices

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

7.2.1. Tastiera

Device implementations:

• MUST include support for the Input Management Framework (which allows third-party developers to create Input Method Editors—ie soft keyboard) as detailed at http://developer.android.com .
• MUST provide at least one soft keyboard implementation (regardless of whether a hard keyboard is present) except for Android Watch devices where the screen size makes it less reasonable to have a soft keyboard.
• MAY include additional soft keyboard implementations.
• MAY include a hardware keyboard.
• MUST NOT include a hardware keyboard that does not match one of the formats specified in android.content.res.Configuration.keyboard [ Resources, 85 ] (QWERTY or 12-key).

7.2.2. Non-touch Navigation

Device implementations:

• MAY omit a non-touch navigation option (trackball, d-pad, or wheel) if the device implementation is not an Android Television device.
• MUST report the correct value for android.content.res.Configuration.navigation [ Resources, 85 ].
• MUST provide a reasonable alternative user interface mechanism for the selection and editing of text, compatible with Input Management Engines. The upstream Android open source implementation includes a selection mechanism suitable for use with devices that lack non-touch navigation inputs.

7.2.3. Navigation Keys

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

• Android Handheld device implementations MUST provide the Home, Recents, and Back functions.
• Android Television device implementations MUST provide the Home and Back functions.
• Android Watch device implementations MUST have the Home function available to the user, and the Back function except for when it is in UI_MODE_TYPE_WATCH.
• Android Automotive implementations MUST provide the Home function and MAY provide Back and Recent functions.
• All other types of device implementations MUST provide the Home and Back functions.

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

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

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

The Menu function is deprecated in favor of action bar since Android 4.0. Therefore the new device implementations shipping with Android 6.0 and later MUST NOT implement a dedicated physical button for the Menu function. Older device implementations SHOULD NOT implement a dedicated physical button for the Menu function, but if the physical Menu button is implemented and the device is running applications with targetSdkVersion > 10, the device implementation:

• MUST display the action overflow button on the action bar when it is visible and the resulting action overflow menu popup is not empty. For a device implementation launched before Android 4.4 but upgrading to Android 6.0, this is RECOMMENDED.
• MUST NOT modify the position of the action overflow popup displayed by selecting the overflow button in the action bar.
• MAY render the action overflow popup at a modified position on the screen when it is displayed by selecting the physical menu button.

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

Android device implementations with the support of the Assist action [ Resources, 30 ] MUST make this accessible with a single action (eg tap, double-click, or gesture) when other navigation keys are visible, and are STRONGLY RECOMMENDED to use the long-press on the Home button or software key as the single action.

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

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

7.2.4. Touchscreen Input

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

• SHOULD support fully independently tracked pointers, if the device input system supports multiple pointers.
• MUST report the value of android.content.res.Configuration.touchscreen [ Resources, 85 ] corresponding to the type of the specific touchscreen on the device.

Android includes support for a variety of touchscreens, touch pads, and fake touch input devices. Touchscreen based device implementations are associated with a display [ Resources, 86 ] such that the user has the impression of directly manipulating items on screen. Since the user is directly touching the screen, the system does not require any additional affordances to indicate the objects being manipulated. In contrast, a fake touch interface provides a user input system that approximates a subset of touchscreen capabilities. For example, a mouse or remote control that drives an on-screen cursor approximates touch, but requires the user to first point or focus then click. Numerous input devices like the mouse, trackpad, gyro-based air mouse, gyro-pointer, joystick, and multi-touch trackpad can support fake touch interactions. Android includes the feature constant android.hardware.faketouch, which corresponds to a high-fidelity non-touch (pointer-based) input device such as a mouse or trackpad that can adequately emulate touch-based input (including basic gesture support), and indicates that the device supports an emulated subset of touchscreen functionality. Device implementations that declare the fake touch feature MUST meet the fake touch requirements in section 7.2.5 .

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

7.2.5. Fake Touch Input

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

• MUST report the absolute X and Y screen positions of the pointer location and display a visual pointer on the screen [ Resources, 87 ].
• MUST report touch event with the action code that specifies the state change that occurs on the pointer going down or up on the screen [ Resources, 87 ].
• MUST support pointer down and up on an object on the screen, which allows users to emulate tap on an object on the screen.
• MUST support pointer down, pointer up, pointer down then pointer up in the same place on an object on the screen within a time threshold, which allows users to emulate double tap on an object on the screen [ Resources, 87 ].
• MUST support pointer down on an arbitrary point on the screen, pointer move to any other arbitrary point on the screen, followed by a pointer up, which allows users to emulate a touch drag.
• MUST support pointer down then allow users to quickly move the object to a different position on the screen and then pointer up on the screen, which allows users to fling an object on the screen.

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

7.2.6. Game Controller Support

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

7.2.6.1. Button Mappings

Android Television device implementations MUST support the following key mappings:

Pulsante	HID Usage 2	Android Button
A 1	0x09 0x0001	KEYCODE_BUTTON_A (96)
B 1	0x09 0x0002	KEYCODE_BUTTON_B (97)
X 1	0x09 0x0004	KEYCODE_BUTTON_X (99)
Y 1	0x09 0x0005	KEYCODE_BUTTON_Y (100)
D-pad up 1 D-pad down 1	0x01 0x0039 3	AXIS_HAT_Y 4
D-pad left 1 D-pad right 1	0x01 0x0039 3	AXIS_HAT_X 4
Left shoulder button 1	0x09 0x0007	KEYCODE_BUTTON_L1 (102)
Right shoulder button 1	0x09 0x0008	KEYCODE_BUTTON_R1 (103)
Left stick click 1	0x09 0x000E	KEYCODE_BUTTON_THUMBL (106)
Right stick click 1	0x09 0x000F	KEYCODE_BUTTON_THUMBR (107)
Casa 1	0x0c 0x0223	KEYCODE_HOME (3)
Back 1	0x0c 0x0224	KEYCODE_BACK (4)

1 [ Resources, 88 ]

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

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

4 [ Resources, 87 ]

Analog Controls 1	HID Usage	Android Button
Left Trigger	0x02 0x00C5	AXIS_LTRIGGER
Right Trigger	0x02 0x00C4	AXIS_RTRIGGER
Left Joystick	0x01 0x0030 0x01 0x0031	AXIS_X AXIS_Y
Right Joystick	0x01 0x0032 0x01 0x0035	AXIS_Z AXIS_RZ

1 [ Resources, 87 ]

7.2.7. Telecomando

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

• Search affordance . Device implementations MUST fire KEYCODE_SEARCH (or KEYCODE_ASSIST if the device supports an assistant) when the user invokes voice search on either the physical or software-based remote.
• Navigation . All Android Television remotes MUST include Back, Home, and Select buttons and support for D-pad events [ Resources, 88 ].

7.3. Sensori

Android includes APIs for accessing a variety of sensor types. Devices implementations generally MAY omit these sensors, as provided for in the following subsections. If a device includes a particular sensor type that has a corresponding API for third-party developers, the device implementation MUST implement that API as described in the Android SDK documentation and the Android Open Source documentation on sensors [ Resources, 89 ]. For example, device implementations:

• MUST accurately report the presence or absence of sensors per the android.content.pm.PackageManager class [ Resources, 70] .
• MUST return an accurate list of supported sensors via the SensorManager.getSensorList() and similar methods.
• MUST behave reasonably for all other sensor APIs (for example, by returning true or false as appropriate when applications attempt to register listeners, not calling sensor listeners when the corresponding sensors are not present; etc.).
• MUST report all sensor measurements using the relevant International System of Units (metric) values for each sensor type as defined in the Android SDK documentation [ Resources, 90 ].
• SHOULD report the event time in nanoseconds as defined in the Android SDK documentation, representing the time the event happened and synchronized with the SystemClock.elapsedRealtimeNano() clock. Existing and new Android devices are STRONGLY RECOMMENDED to meet these requirement so they will be able to upgrade to the future platform releases where this might become a REQUIRED component. The synchronization error SHOULD be below 100 milliseconds [ Resources, 91 ].
• MUST report sensor data with a maximum latency of 100 milliseconds + 2 * sample_time for the case of a sensor streamed with a minimum required latency of 5 ms + 2 * sample_time when the application processor is active. This delay does not include any filtering delays.
• MUST report the first sensor sample within 400 milliseconds + 2 * sample_time of the sensor being activated. It is acceptable for this sample to have an accuracy of 0.

The list above is not comprehensive; the documented behavior of the Android SDK and the Android Open Source Documentations on Sensors [ Resources, 89 ] is to be considered authoritative.

Some sensor types are composite, meaning they can be derived from data provided by one or more other sensors. (Examples include the orientation sensor, and the linear acceleration sensor.) Device implementations SHOULD implement these sensor types, when they include the prerequisite physical sensors as described in [ Resources, 92 ]. If a device implementation includes a composite sensor it MUST implement the sensor as described in the Android Open Source documentation on composite sensors [ Resources, 92 ].

Some Android sensors support a “continuous” trigger mode, which returns data continuously [ Resources, 93 ]. For any API indicated by the Android SDK documentation to be a continuous sensor, device implementations MUST continuously provide periodic data samples that SHOULD have a jitter below 3%, where jitter is defined as the standard deviation of the difference of the reported timestamp values between consecutive events.

Note that the device implementations MUST ensure that the sensor event stream MUST NOT prevent the device CPU from entering a suspend state or waking up from a suspend state.

Finally, when several sensors are activated, the power consumption SHOULD NOT exceed the sum of the individual sensor's reported power consumption.

7.3.1. Accelerometro

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

• MUST implement and report TYPE_ACCELEROMETER sensor [ Resources, 94 ].
• MUST be able to report events up to a frequency of at least 50 Hz for Android Watch devices as such devices have a stricter power constraint and 100 Hz for all other device types.
• SHOULD report events up to at least 200 Hz.
• MUST comply with the Android sensor coordinate system as detailed in the Android APIs [ Resources, 90 ].
• MUST be capable of measuring from freefall up to four times the gravity (4g) or more on any axis.
• MUST have a resolution of at least 12-bits and SHOULD have a resolution of at least 16-bits.
• SHOULD be calibrated while in use if the characteristics changes over the life cycle and compensated, and preserve the compensation parameters between device reboots.
• SHOULD be temperature compensated.
• MUST have a standard deviation no greater than 0.05 m/s^, where the standard deviation should be calculated on a per axis basis on samples collected over a period of at least 3 seconds at the fastest sampling rate.
• SHOULD implement the TYPE_SIGNIFICANT_MOTION, TYPE_TILT_DETECTOR, TYPE_STEP_DETECTOR, TYPE_STEP_COUNTER composite sensors as described in the Android SDK document. Existing and new Android devices are STRONGLY RECOMMENDED to implement the TYPE_SIGNIFICANT_MOTION composite sensor. If any of these sensors are implemented, the sum of their power consumption MUST always be less than 4 mW and SHOULD each be below 2 mW and 0.5 mW for when the device is in a dynamic or static condition.
• If a gyroscope sensor is included, MUST implement the TYPE_GRAVITY and TYPE_LINEAR_ACCELERATION composite sensors and SHOULD implement the TYPE_GAME_ROTATION_VECTOR composite sensor. Existing and new Android devices are STRONGLY RECOMMENDED to implement the TYPE_GAME_ROTATION_VECTOR sensor.
• MUST implement a TYPE_ROTATION_VECTOR composite sensor, if a gyroscope sensor and a magnetometer sensor is also included.

7.3.2. Magnetometro

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

• MUST implement the TYPE_MAGNETIC_FIELD sensor and SHOULD also implement TYPE_MAGNETIC_FIELD_UNCALIBRATED sensor. Existing and new Android devices are STRONGLY RECOMMENDED to implement the TYPE_MAGNETIC_FIELD_UNCALIBRATED sensor.
• MUST be able to report events up to a frequency of at least 10 Hz and SHOULD report events up to at least 50 Hz.
• MUST comply with the Android sensor coordinate system as detailed in the Android APIs [ Resources, 90 ].
• MUST be capable of measuring between -900 µT and +900 µT on each axis before saturating.
• MUST have a hard iron offset value less than 700 µT and SHOULD have a value below 200 µT, by placing the magnetometer far from dynamic (current-induced) and static (magnet-induced) magnetic fields.
• MUST have a resolution equal or denser than 0.6 µT and SHOULD have a resolution equal or denser than 0.2 µ.
• SHOULD be temperature compensated.
• MUST support online calibration and compensation of the hard iron bias, and preserve the compensation parameters between device reboots.
• MUST have the soft iron compensation applied—the calibration can be done either while in use or during the production of the device.
• SHOULD have a standard deviation, calculated on a per axis basis on samples collected over a period of at least 3 seconds at the fastest sampling rate, no greater than 0.5 µT.
• MUST implement a TYPE_ROTATION_VECTOR composite sensor, if an accelerometer sensor and a gyroscope sensor is also included.
• MAY implement the TYPE_GEOMAGNETIC_ROTATION_VECTOR sensor if an accelerometer sensor is also implemented. However if implemented, it MUST consume less than 10 mW and SHOULD consume less than 3 mW when the sensor is registered for batch mode at 10 Hz.

7.3.3. GPS

Device implementations SHOULD include a GPS 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. Giroscopio

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

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

7.3.5. Barometro

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

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

7.3.6. Termometro

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

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

7.3.7. Photometer

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

7.3.8. Proximity Sensor

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

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

7.3.9. High Fidelity Sensors

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

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

• SENSOR_TYPE_ACCELEROMETER
  • MUST have a measurement range between at least -8g and +8g
  • MUST have a measurement resolution of at least 1024 LSB/G
  • MUST have a minimum measurement frequency of 12.5 Hz or lower
  • MUST have a maxmium measurement frequency of 200 Hz or higher
  • MUST have a measurement noise not above 400uG/√Hz
  • MUST implement a non-wake-up form of this sensor with a buffering capability of at least 3000 sensor events
  • MUST have a batching power consumption not worse than 3 mW
• SENSOR_TYPE_GYROSCOPE
  • MUST have a measurement range between at least -1000 and +1000 dps
  • MUST have a measurement resolution of at least 16 LSB/dps
  • MUST have a minimum measurement frequency of 12.5 Hz or lower
  • MUST have a maxmium measurement frequency of 200 Hz or higher
  • MUST have a measurement noise not above 0.014°/s/√Hz
• SENSOR_TYPE_GYROSCOPE_UNCALIBRATED with the same quality requirements as SENSOR_TYPE_GYROSCOPE
• SENSOR_TYPE_GEOMAGNETIC_FIELD
  • MUST have a measurement range between at least -900 and +900 uT
  • MUST have a measurement resolution of at least 5 LSB/uT
  • MUST have a minimum measurement frequency of 5 Hz or lower
  • MUST have a maxmium measurement frequency of 50 Hz or higher
  • MUST have a measurement noise not above 0.5 uT
• SENSOR_TYPE_MAGNETIC_FIELD_UNCALIBRATED with the same quality requirements as SENSOR_TYPE_GEOMAGNETIC_FIELD and in addition:
  • MUST implement a non-wake-up form of this sensor with a buffering capability of at least 600 sensor events
• SENSOR_TYPE_PRESSURE
  • MUST have a measurement range between at least 300 and 1100 hPa
  • MUST have a measurement resolution of at least 80 LSB/hPa
  • MUST have a minimum measurement frequency of 1 Hz or lower
  • MUST have a maximum measurement frequency of 10 Hz or higher
  • MUST have a measurement noise not above 2 Pa/√Hz
  • MUST implement a non-wake-up form of this sensor with a buffering capability of at least 300 sensor events
  • MUST have a batching power consumption not worse than 2 mW
• TYPE_GAME_ROTATION_VECTOR
  • MUST implement a non-wake-up form of this sensor with a buffering capability of at least 300 sensor events.
  • MUST have a batching power consumption not worse than 4 mW.
• SENSOR_TYPE_SIGNIFICANT_MOTION
  • MUST have a power consumption not worse than 0.5 mW when device is static and 1.5 mW when device is moving
• SENSOR_TYPE_STEP_DETECTOR
  • MUST implement a non-wake-up form of this sensor with a buffering capability of at least 100 sensor events
  • MUST have a power consumption not worse than 0.5 mW when device is static and 1.5 mW when device is moving
  • MUST have a batching power consumption not worse than 4 mW
• SENSOR_TYPE_STEP_COUNTER
  • MUST have a power consumption not worse than 0.5 mW when device is static and 1.5 mW when device is moving
• SENSOR_TILT_DETECTOR
  • MUST have a power consumption not worse than 0.5 mW when device is static and 1.5 mW when device is moving

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

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

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

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

• SENSOR_TYPE_PROXIMITY: 100 sensor events

7.3.10. Sensore di impronte digitali

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

• MUST declare support for the android.hardware.fingerprint feature.
• MUST fully implement the corresponding API as described in the Android SDK documentation [ Resources, 95 ].
• MUST have a false acceptance rate not higher than 0.002%.
• Is STRONGLY RECOMMENDED to have a false rejection rate of less than 10%, as measured on the device
• Is STRONGLY RECOMMENDED to have a latency below 1 second, measured from when the fingerprint sensor is touched until the screen is unlocked, for one enrolled finger.
• MUST rate limit attempts for at least 30 seconds after five false trials for fingerprint verification.
• MUST have a hardware-backed keystore implementation, and perform the fingerprint matching in a Trusted Execution Environment (TEE) or on a chip with a secure channel to the TEE.
• MUST have all identifiable fingerprint data encrypted and cryptographically authenticated such that they cannot be acquired, read or altered outside of the Trusted Execution Environment (TEE) as documented in the implementation guidelines on the Android Open Source Project site [ Resources, 96 ].
• MUST prevent adding a fingerprint without first establishing a chain of trust by having the user confirm existing or add a new device credential (PIN/pattern/password) that's secured by TEE; the Android Open Source Project implementation provides the mechanism in the framework to do so.
• MUST NOT enable 3rd-party applications to distinguish between individual fingerprints.
• MUST honor the DevicePolicyManager.KEYGUARD_DISABLE_FINGERPRINT flag.
• MUST, when upgraded from a version earlier than Android 6.0, have the fingerprint data securely migrated to meet the above requirements or removed.
• SHOULD use the Android Fingerprint icon provided in the Android Open Source Project.

7.4. Data Connectivity

7.4.1. Telefonia

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

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

7.4.2. IEEE 802.11 (Wi-Fi)

Android Television device implementations MUST include support for one or more forms of 802.11 (b/g/a/n, etc.) and other types of Android device implementation SHOULD include support for one or more forms of 802.11. If a device implementation does include support for 802.11 and exposes the functionality to a third-party application, it MUST implement the corresponding Android API and:

• MUST report the hardware feature flag android.hardware.wifi.
• MUST implement the multicast API as described in the SDK documentation [ Resources, 97 ].
• MUST support multicast DNS (mDNS) and MUST NOT filter mDNS packets (224.0.0.251) at any time of operation including:
  • Even when the screen is not in an active state.
  • For Android Television device implementations, even when in standby power states.

7.4.2.1. Wi-Fi diretto

Device implementations SHOULD include support for Wi-Fi Direct (Wi-Fi peer-to-peer). If a device implementation does include support for Wi-Fi Direct, it MUST implement the corresponding Android API as described in the SDK documentation [ Resources, 98 ]. If a device implementation includes support for Wi-Fi Direct, then it:

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

7.4.2.2. Wi-Fi Tunneled Direct Link Setup

Android Television device implementations MUST include support for Wi-Fi Tunneled Direct Link Setup (TDLS) and other types of Android device implementations SHOULD include support for Wi-Fi TDLS as described in the Android SDK Documentation [ Resources, 99 ]. If a device implementation does include support for TDLS and TDLS is enabled by the WiFiManager API, the device:

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

7.4.3. Bluetooth

Android includes support for Bluetooth and Bluetooth Low Energy [ Resources, 100 ]. Device implementations that include support for Bluetooth and Bluetooth Low Energy MUST declare the relevant platform features (android.hardware.bluetooth and android.hardware.bluetooth_le respectively) and implement the platform APIs. Device implementations SHOULD implement relevant Bluetooth profiles such as A2DP, AVCP, OBEX, etc. as appropriate for the device. Android Television device implementations MUST support Bluetooth and Bluetooth LE.

Device implementations including support for Bluetooth Low Energy:

• MUST declare the hardware feature android.hardware.bluetooth_le.
• MUST enable the GATT (generic attribute profile) based Bluetooth APIs as described in the SDK documentation and [ Resources, 100 ].
• are STRONGLY RECOMMENDED to implement a Resolvable Private Address (RPA) timeout no longer than 15 minutes and rotate the address at timeout to protect user privacy.
• SHOULD support offloading of the filtering logic to the bluetooth chipset when implementing the ScanFilter API [ Resources, 101 ], and MUST report the correct value of where the filtering logic is implemented whenever queried via the android.bluetooth.BluetoothAdapter.isOffloadedFilteringSupported() method.
• SHOULD support offloading of the batched scanning to the bluetooth chipset, but if not supported, MUST report 'false' whenever queried via the android.bluetooth.BluetoothAdapater.isOffloadedScanBatchingSupported() method.
• SHOULD support multi advertisement with at least 4 slots, but if not supported, MUST report 'false' whenever queried via the android.bluetooth.BluetoothAdapter.isMultipleAdvertisementSupported() method.

7.4.4. Near-Field Communications

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

• MUST report the android.hardware.nfc feature from the android.content.pm.PackageManager.hasSystemFeature() method [ Resources, 70 ].
• MUST be capable of reading and writing NDEF messages via the following NFC standards:
  • MUST be capable of acting as an NFC Forum reader/writer (as defined by the NFC Forum technical specification NFCForum-TS-DigitalProtocol-1.0) via the following NFC standards:
    • NfcA (ISO14443-3A)
    • NfcB (ISO14443-3B)
    • NfcF (JIS X 6319-4)
    • IsoDep (ISO 14443-4)
    • NFC Forum Tag Types 1, 2, 3, 4 (defined by the NFC Forum)
  • STRONGLY RECOMMENDED to be capable of reading and writing NDEF messages as well as raw data via the following NFC standards. Note that while the NFC standards below are stated as STRONGLY RECOMMENDED, the Compatibility Definition for a future version is planned to change these to MUST. These standards are optional in this version but will be required in future versions. Existing and new devices that run this version of Android are very strongly encouraged to meet these requirements now so they will be able to upgrade to the future platform releases.
    • NfcV (ISO 15693)
  • SHOULD be capable of reading the barcode and URL (if encoded) of Thinfilm NFC Barcode [ Resources, 102 ] products.
  • MUST be capable of transmitting and receiving data via the following peer-to-peer standards and protocols:
    • ISO 18092
    • LLCP 1.2 (defined by the NFC Forum)
    • SDP 1.0 (defined by the NFC Forum)
    • NDEF Push Protocol [ Resources, 103 ]
    • SNEP 1.0 (defined by the NFC Forum)
  • MUST include support for Android Beam [ Resources, 104 ]:
    • MUST implement the SNEP default server. Valid NDEF messages received by the default SNEP server MUST be dispatched to applications using the android.nfc.ACTION_NDEF_DISCOVERED intent. Disabling Android Beam in settings MUST NOT disable dispatch of incoming NDEF message.
    • MUST honor the android.settings.NFCSHARING_SETTINGS intent to show NFC sharing settings [ Resources, 105 ].
    • MUST implement the NPP server. Messages received by the NPP server MUST be processed the same way as the SNEP default server.
    • MUST implement a SNEP client and attempt to send outbound P2P NDEF to the default SNEP server when Android Beam is enabled. If no default SNEP server is found then the client MUST attempt to send to an NPP server.
    • MUST allow foreground activities to set the outbound P2P NDEF message using android.nfc.NfcAdapter.setNdefPushMessage, and android.nfc.NfcAdapter.setNdefPushMessageCallback, and android.nfc.NfcAdapter.enableForegroundNdefPush.
    • SHOULD use a gesture or on-screen confirmation, such as 'Touch to Beam', before sending outbound P2P NDEF messages.
    • SHOULD enable Android Beam by default and MUST be able to send and receive using Android Beam, even when another proprietary NFC P2p mode is turned on.
    • MUST support NFC Connection handover to Bluetooth when the device supports Bluetooth Object Push Profile. Device implementations MUST support connection handover to Bluetooth when using android.nfc.NfcAdapter.setBeamPushUris, by implementing the “Connection Handover version 1.2” [ Resources, 106 ] and “Bluetooth Secure Simple Pairing Using NFC version 1.0” [ Resources, 107 ] specs from the NFC Forum. Such an implementation MUST implement the handover LLCP service with service name “urn:nfc:sn:handover” for exchanging the handover request/select records over NFC, and it MUST use the Bluetooth Object Push Profile for the actual Bluetooth data transfer. For legacy reasons (to remain compatible with Android 4.1 devices), the implementation SHOULD still accept SNEP GET requests for exchanging the handover request/select records over NFC. However an implementation itself SHOULD NOT send SNEP GET requests for performing connection handover.
  • MUST poll for all supported technologies while in NFC discovery mode.
  • SHOULD be in NFC discovery mode while the device is awake with the screen active and the lock-screen unlocked.

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

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

• MUST report the android.hardware.nfc.hce feature constant.
• MUST support NFC HCE APIs as defined in the Android SDK [ Resources, 108 ].

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

• MIFARE Classic
• MIFARE Ultralight
• NDEF on MIFARE Classic

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

• MUST implement the corresponding Android APIs as documented by the Android SDK.
• MUST report the feature com.nxp.mifare from the android.content.pm.PackageManager.hasSystemFeature() method [ Resources, 70 ]. Note that this is not a standard Android feature and as such does not appear as a constant in the android.content.pm.PackageManager class.
• MUST NOT implement the corresponding Android APIs nor report the com.nxp.mifare feature unless it also implements general NFC support as described in this section.

If a device implementation does not include NFC hardware, it MUST NOT declare the android.hardware.nfc feature from the android.content.pm.PackageManager.hasSystemFeature() method [ Resources, 70 ], and MUST implement the Android NFC API as a no-op.

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

7.4.5. Minimum Network Capability

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

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

Devices MAY implement more than one form of data connectivity.

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

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

IPv6 MUST be enabled by default.

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

IPv6 connectivity MUST be maintained in doze mode.

7.4.6. Sync Settings

Device implementations MUST have the master auto-sync setting on by default so that the method getMasterSyncAutomatically() returns “true” [ Resources, 109 ].

7.5. Macchine fotografiche

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

If a device implementation includes at least one camera, it SHOULD be possible for an application to simultaneously allocate 3 bitmaps equal to the size of the images produced by the largest-resolution camera sensor on the device.

7.5.1. Rear-Facing Camera

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

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

7.5.2. Fotocamera frontale

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

• MUST report the feature flag android.hardware.camera.any and android.hardware.camera.front.
• MUST have a resolution of at least VGA (640x480 pixels).
• MUST NOT use a front-facing camera as the default for the Camera API. The camera API in Android has specific support for front-facing cameras and device implementations MUST NOT configure the API to to treat a front-facing camera as the default rear-facing camera, even if it is the only camera on the device.
• MAY include features (such as auto-focus, flash, etc.) available to rear-facing cameras as described in section 7.5.1 .
• MUST horizontally reflect (ie mirror) the stream displayed by an app in a CameraPreview, as follows:
  • If the device implementation is capable of being rotated by user (such as automatically via an accelerometer or manually via user input), the camera preview MUST be mirrored horizontally relative to the device's current orientation.
  • If the current application has explicitly requested that the Camera display be rotated via a call to the android.hardware.Camera.setDisplayOrientation()[ Resources, 110 ] method, the camera preview MUST be mirrored horizontally relative to the orientation specified by the application.
  • Otherwise, the preview MUST be mirrored along the device's default horizontal axis.
• MUST mirror the image displayed by the postview in the same manner as the camera preview image stream. If the device implementation does not support postview, this requirement obviously does not apply.
• MUST NOT mirror the final captured still image or video streams returned to application callbacks or committed to media storage.

7.5.3. External Camera

Device implementations with USB host mode MAY include support for an external camera that connects to the USB port. If a device includes support for an external camera, it:

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

Video compression (such as MJPEG) support is RECOMMENDED to enable transfer of high-quality unencoded streams (ie raw or independently compressed picture streams). Camera-based video encoding MAY be supported. If so, a simultaneous unencoded/ MJPEG stream (QVGA or greater resolution) MUST be accessible to the device implementation.

7.5.4. Camera API Behavior

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

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

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

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

Device implementations MUST still implement the full Camera API included in the Android SDK documentation [ Resources, 111 ], regardless of whether the device includes hardware autofocus or other capabilities. For instance, cameras that lack autofocus MUST still call any registered android.hardware.Camera.AutoFocusCallback instances (even though this has no relevance to a non-autofocus camera.) Note that this does apply to front-facing cameras; for instance, even though most front-facing cameras do not support autofocus, the API callbacks must still be “faked” as described.

Device implementations MUST recognize and honor each parameter name defined as a constant on the android.hardware.Camera.Parameters class, if the underlying hardware supports the feature. If the device hardware does not support a feature, the API must behave as documented. Conversely, device implementations MUST NOT honor or recognize string constants passed to the android.hardware.Camera.setParameters() method other than those documented as constants on the android.hardware.Camera.Parameters. That is, device implementations MUST support all standard Camera parameters if the hardware allows, and MUST NOT support custom Camera parameter types. For instance, device implementations that support image capture using high dynamic range (HDR) imaging techniques MUST support camera parameter Camera.SCENE_MODE_HDR [ Resources, 112 ].

Because not all device implementations can fully support all the features of the android.hardware.camera2 API, device implementations MUST report the proper level of support with the android.info.supportedHardwareLevel property as described in the Android SDK [ Resources, 113 ] and report the appropriate framework feature flags [ Resources, 114 ].

Device implementations MUST also declare its Individual camera capabilities of android.hardware.camera2 via the android.request.availableCapabilities property and declare the appropriate feature flags [ Resources, 114 ]; a device must define the feature flag if any of its attached camera devices supports the feature.

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

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

7.5.5. Camera Orientation

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

7.6. Memoria e archiviazione

7.6.1. Minimum Memory and Storage

The memory available to the kernel and userspace on device implementations MUST be at least equal or larger than the minimum values specified by the following table. (See section 7.1.1 for screen size and density definitions.)

Density and screen size	32-bit device	64-bit device
Android Watch devices (due to smaller screens)	416MB	Non applicabile
280dpi or lower on small/normal screens mdpi or lower on large screens ldpi or lower on extra large screens	424MB	704MB
xhdpi or higher on small/normal screens hdpi or higher on large screens mdpi or higher on extra large screens	512MB	832MB
400dpi or higher on small/normal screens xhdpi or higher on large screens tvdpi or higher on extra large screens	896MB	1280MB
560dpi or higher on small/normal screens 400dpi or higher on large screens xhdpi or higher on extra large screens	1344MB	1824MB

The minimum memory values MUST be in addition to any memory space already dedicated to hardware components such as radio, video, and so on that is not under the kernel's control.

Device implementations with less than 512MB of memory available to the kernel and userspace, unless an Android Watch, MUST return the value "true" for ActivityManager.isLowRamDevice().

Android Television devices MUST have at least 5GB and other device implementations MUST have at least 1.5GB of non-volatile storage available for application private data. That is, the /data partition MUST be at least 5GB for Android Television devices and at least 1.5GB for other device implementations. Device implementations that run Android are STRONGLY RECOMMENDED to have at least 3GB of non-volatile storage for application private data so they will be able to upgrade to the future platform releases.

The Android APIs include a Download Manager that applications MAY use to download data files [ Resources, 115 ]. The device implementation of the Download Manager MUST be capable of downloading individual files of at least 100MB in size to the default “cache" location.

7.6.2. Application Shared Storage

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

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

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

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

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

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

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

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

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

• SHOULD be compatible with the reference Android MTP host, Android File Transfer [ Resources, 116 ].
• SHOULD report a USB device class of 0x00.
• SHOULD report a USB interface name of 'MTP'.

7.6.3. Adoptable Storage

Device implementations are STRONGLY RECOMMENDED to implement adoptable storage if the removable storage device port is in a long-term stable location, such as within the battery compartment or other protective cover [ Resources, 117 ].

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

7.7. USB

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

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

• The port MUST be connectable to a USB host that has a standard type-A or type -C USB port.
• The port SHOULD use micro-B, micro-AB or Type-C USB form factor. Existing and new Android devices are STRONGLY RECOMMENDED to meet these requirements so they will be able to upgrade to future platform releases.
• The port SHOULD either be located on the bottom of the device (according to natural orientation) or enable software screen rotation for all apps (including home screen), so that the display draws correctly when the device is oriented with the port at bottom. Existing and new Android devices are STRONGLY RECOMMENDED to meet these requirements so they will be able to upgrade to future platform releases.
• It SHOULD implement the Android Open Accessory (AOA) API and specification as documented in the Android SDK documentation, and if it is an Android Handheld device it MUST implement the AOA API. Device implementations implementing the AOA specification:
  • MUST declare support for the hardware feature android.hardware.usb.accessory [ Resources, 118 ].
  • MUST support establishing an AOA protocol based communication on first time connection with a USB host machine that acts as an accessory, without the need for the user to change the default USB mode.
  • MUST implement the USB audio class as documented in the Android SDK documentation [ Resources, 119 ].
  • And also the USB mass storage class, MUST include the string "android" at the end of the interface description iInterface string of the USB mass storage
• It SHOULD implement support to draw 1.5 A current during HS chirp and traffic as specified in the USB Battery Charging Specification, Revision 1.2 [ Resources, 120 ]. Existing and new Android devices are STRONGLY RECOMMENDED to meet these requirements so they will be able to upgrade to the future platform releases.
the Type-C resistor standard.
• The value of iSerialNumber in USB standard device descriptor MUST be equal to the value of android.os.Build.SERIAL.

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

• SHOULD use a type-C USB port, if the device implementation supports USB 3.1.
• MAY use a non-standard port form factor, but if so MUST ship with a cable or cables adapting the port to a standard type-A or type-C USB port.
• MAY use a micro-AB USB port, but if so SHOULD ship with a cable or cables adapting the port to a standard type-A or type-C USB port.
• is STRONGLY RECOMMENDED to implement the USB audio class as documented in the Android SDK documentation [ Resources, 119 ].
• 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, 121 ].
• SHOULD support device charging while in host mode; advertising a source current of at least 1.5A as specified in the Termination Parameters section of the USB Type-C Cable and Connector Specification, Revision 1.2 [ ] for USB Type-C connectors or using Charging Downstream Port(CDP) output current range as specified in the USB Battery Charging Specification, Revision 1.2 [ Resources, 120 ] for Micro-AB connectors.

7.8. Audio

7.8.1. Microfono

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

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

7.8.2. Uscita audio

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

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

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

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

7.8.2.1. Analog Audio Ports

In order to be compatible with the headsets and other audio accessories using the 3.5mm audio plug across the Android ecosystem [ Resources, 122 ], if a device implementation includes one or more analog audio ports, at least one of the audio port(s) SHOULD be a 4 conductor 3.5mm audio jack. If a device implementation has a 4 conductor 3.5mm audio jack, it:

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

7.8.3. Near-Ultrasound

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

• If PROPERTY_SUPPORT_MIC_NEAR_ULTRASOUND is "true", then
  • The microphone's mean power response in the 18.5 kHz to 20 kHz band MUST be no more than 15 dB below the response at 2 kHz.
  • The microphone's unweighted signal-to-noise ratio (SNR) over 18.5 kHz to 20 kHz for a 19 kHz tone at -26 dBFS MUST be no lower than 50 dB.
• If PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND is "true", then the speaker's mean response in 18.5 kHz - 20 kHz MUST be no lower than 40 dB below the response at 2 kHz.

8. Performance and Power

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

8.1. User Experience Consistency

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

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

8.2. File I/O Access Performance

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

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

8.3. Power-Saving Modes

All apps exempted from App Standby and/or Doze mode MUST be made visible to the end user. Further, the triggering, maintenance, wakeup algorithms and the use of Global system settings of these power-saving modes MUST not deviate from the Android Open Source Project.

8.4. Power Consumption Accounting

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

• MUST be able to track hardware component power usage and attribute that power usage to specific applications. Specifically, implementations:
  • MUST provide a per-component power profile that defines the current consumption value for each hardware component and the approximate battery drain caused by the components over time as documented in the Android Open Source Project site [ Resources, 123 ].
  • MUST report all power consumption values in milliampere hours (mAh)
  • SHOULD be attributed to the hardware component itself if unable to attribute hardware component power usage to an application.
  • MUST report CPU power consumption per each process's UID. The Android Open Source Project meets the requirement through the uid_cputime kernel module implementation.
• MUST make this power usage available via the adb shell dumpsys batterystats shell command to the app developer [ Resources, 124 ].
• MUST honor the android.intent.action.POWER_USAGE_SUMMARY intent and display a settings menu that shows this power usage [ Resources, 125 ].

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, 126 ] in the Android developer documentation. Device implementations MUST support installation of self-signed applications without requiring any additional permissions/certificates from any third parties/authorities. Specifically, compatible devices MUST support the security mechanisms described in the follow subsections.

9.1. Autorizzazioni

Device implementations MUST support the Android permissions model as defined in the Android developer documentation [ Resources, 126 ]. Specifically, implementations MUST enforce each permission defined as described in the SDK documentation; no permissions may be omitted, altered, or ignored. Implementations MAY add additional permissions, provided the new permission ID strings are not in the android.* namespace.

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

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

9.2. UID and Process Isolation

Device implementations MUST support the Android application sandbox model, in which each application runs as a unique Unixstyle UID and in a separate process. Device implementations MUST support running multiple applications as the same Linux user ID, provided that the applications are properly signed and constructed, as defined in the Security and Permissions reference [ Resources, 126 ].

9.3. Filesystem Permissions

Device implementations MUST support the Android file access permissions model as defined in the Security and Permissions reference [ Resources, 126 ].

9.4. Alternate Execution Environments

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

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

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

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

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

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

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

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

9.5. Multi-User Support

Android includes support for multiple users and provides support for full user isolation [ Resources, 127 ]. Device implementations MAY enable multiple users, but when enabled MUST meet the following requirements related to multi-user support [ Resources, 128 ]:

• Device implementations that do not declare the android.hardware.telephony feature flag MUST support restricted profiles, a feature that allows device owners to manage additional users and their capabilities on the device. With restricted profiles, device owners can quickly set up separate environments for additional users to work in, with the ability to manage finer-grained restrictions in the apps that are available in those environments.
• Conversely device implementations that declare the android.hardware.telephony feature flag MUST NOT support restricted profiles but MUST align with the AOSP implementation of controls to enable /disable other users from accessing the voice calls and SMS.
• Device implementations MUST, for each user, implement a security model consistent with the Android platform security model as defined in Security and Permissions reference document in the APIs [ Resources, 126 ].
• Each user instance on an Android device MUST have separate and isolated external storage directories. Device implementations MAY store multiple users' data on the same volume or filesystem. However, the device implementation MUST ensure that applications owned by and running on behalf a given user cannot list, read, or write to data owned by any other user. Note that removable media, such as SD card slots, can allow one user to access another's data by means of a host PC. For this reason, device implementations that use removable media for the primary external storage APIs MUST encrypt the contents of the SD card if multiuser is enabled using a key stored only on non-removable media accessible only to the system. As this will make the media unreadable by a host PC, device implementations will be required to switch to MTP or a similar system to provide host PCs with access to the current user's data. Accordingly, device implementations MAY but SHOULD NOT enable multi-user if they use removable media [ Resources, 129 ] for primary external storage.

9.6. Premium SMS Warning

Android includes support for warning users of any outgoing premium SMS message [ Resources, 130 ]. Premium SMS messages are text messages sent to a service registered with a carrier that may incur a charge to the user. Device implementations that declare support for android.hardware.telephony MUST warn users before sending a SMS message to numbers identified by regular expressions defined in /data/misc/sms/codes.xml file in the device. The upstream Android Open Source Project provides an implementation that satisfies this requirement.

9.7. Kernel Security Features

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

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

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

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

Device implementations:

• MUST set SELinux to global enforcing mode.
• MUST configure all domains in enforcing mode. No permissive mode domains are allowed, including domains specific to a device/vendor.
• MUST NOT modify, omit, or replace the neverallow rules present within the external/sepolicy folder provided in the upstream Android Open Source Project (AOSP) and the policy MUST compile with all neverallow rules present, for both AOSP SELinux domains as well as device/vendor specific domains.

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

9.8. Privacy

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

If a device implementation has a mechanism that routes network data traffic through a proxy server or VPN gateway by default (for example, preloading a VPN service with android.permission.CONTROL_VPN granted), the device implementation MUST ask for the user's consent before enabling that meccanismo.

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

9.9. Full-Disk Encryption

If the device implementation supports a secure lock screen reporting " true " for KeyguardManager.isDeviceSecure() [ Resources, 131 ], and is not a device with restricted memory as reported through the ActivityManager.isLowRamDevice() method, then the device MUST support full-disk encryption [ Resources, 132 ] of the application private data (/data partition), as well as the application shared storage partition (/sdcard partition) if it is a permanent, non-removable part of the device.

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

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

9.10. Verified Boot

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

• Declare the platform feature flag android.software.verified_boot
• Perform verification on every boot sequence
• Start verification from an immutable hardware key that is the root of trust, and go all the way up to the system partition
• Implement each stage of verification to check the integrity and authenticity of all the bytes in the next stage before executing the code in the next stage
• Use verification algorithms as strong as current recommendations from NIST for hashing algorithms (SHA-256) and public key sizes (RSA-2048)

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

Starting from Android 6.0, device implementations with Advanced Encryption Standard (AES) crypto performance above 50MiB/seconds MUST support verified boot for device integrity. If a device implementation is already launched without supporting verified boot on an earlier version of Android, such a device can not add support for this feature with a system software update and thus are exempted from the requirement.

9.11. Keys and Credentials

The Android Keystore System [ Resources, 133 ] allows app developers to store cryptographic keys in a container and use them in cryptographic operations through the KeyChain API [ Resources, 134 ] or the Keystore API [ Resources, 135 ].

All Android device implementations MUST meet the following requirements:

• SHOULD not limit the number of keys that can be generated, and MUST at least allow more than 8,192 keys to be imported.
• The lock screen authentication MUST rate limit attempts and SHOULD have an exponential backoff algorithm as implemented in the Android Open Source Project.
• When the device implementation supports a secure lock screen and has a secure hardware such as a Secure Element (SE) where a Trusted Execution Environment (TEE) can be implemented, then it:
  • Is STRONGLY RECOMMENDED to back up the keystore implementation with the secure hardware. The upstream Android Open Source Project provides the Keymaster Hardware Abstraction Layer (HAL) implementation that can be used to satisfy this requirement.
  • MUST perform the lock screen authentication in the secure hardware if the device has a hardware-backed keystore implementation and only when successful allow the authentication-bound keys to be used. The upstream Android Open Source Project provides the Gatekeeper Hardware Abstraction Layer (HAL) that can be used to satisfy this requirement [ Resources, 136 ].

Note that while the above TEE-related requirements are stated as STRONGLY RECOMMENDED, the Compatibility Definition for the next API version is planned to changed these to REQUIRED. If a device implementation is already launched on an earlier Android version and has not implemented a trusted operating system on the secure hardware, such a device might not be able to meet the requirements through a system software update and thus is STRONGLY RECOMMENDED to implement a TEE .

9.12. Data Deletion

Devices MUST provide users with a mechanism to perform a "Factory Data Reset" that allows logical and physical deletion of all data except for the system image and data in other partitions that can be regarded as part of the system image. This MUST satisfy relevant industry standards for data deletion such as NIST SP800-88. This MUST be used for the implementation of the wipeData() API (part of the Android Device Administration API) described in section 3.9 Device Administration .

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

10. Software Compatibility Testing

Device implementations MUST pass all tests described in this section.

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

10.1. Compatibility Test Suite

Device implementations MUST pass the Android Compatibility Test Suite (CTS) [ Resources, 137 ] available from the Android Open Source Project, using the final shipping software on the device. Additionally, device implementers SHOULD use the reference implementation in the Android Open Source tree as much as possible, and MUST ensure compatibility in cases of ambiguity in CTS and for any reimplementations of parts of the reference source code.

The CTS is designed to be run on an actual device. Like any software, the CTS may itself contain bugs. The CTS will be versioned independently of this Compatibility Definition, and multiple revisions of the CTS may be released for Android 6.0. Device implementations MUST pass the latest CTS version available at the time the device software is completed.

10.2. CTS Verifier

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

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

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

11. Updatable Software

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

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

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

However, if the device implementation includes support for an unmetered data connection such as 802.11 or Bluetooth PAN (Personal Area Network) profile:

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

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

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

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

Android includes features that allow the Device Owner app (if present) to control the installation of system updates. To facilitate this, the system update subsystem for devices that report android.software.device_admin MUST implement the behavior described in the SystemUpdatePolicy class [ Resources, 138 ].

12. Document Changelog

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

Sezione	Sommario dei cambiamenti
Vari	Replaced instances of the "encouraged" term with "RECOMMENDED"
2. Device Types	Update for Android Automotive implementations
3.2.2. Build Parameters	Additions for the hardware serial number and for the security patch level of a build
3.2.3.2. Intent Resolution	Section renamed from "Intent Overrides" to "Intent Resolution," with new requirements related to authoritative default app linking
3.3.1. Application Binary Interfaces	Additions for Android ABI support; change related to Vulkan library name
3.4.1. WebView Compatibility	Change for the user agent string reported by the WebView
3.7. Runtime Compatibility	Updates to memory allocation table
3.8.4. Ricerca	Updates regarding Assistant requirements
3.8.6. Temi	Added requirement to support black system icons when requested by the SYSTEM_UI_FLAG_LIGHT_STATUS_BAR flag
3.8.8. Activity Switching	Relaxed Overview title count requirement.
3.8.10. Lock Screen Media Control	Lock Screen Media Control to refer to 3.8.3 in detail.
3.9.1. Device Provisioning	Contains new sections for device owner provisioning and managed profile provisioning
3.9.2. Managed Profile Support	New section with requirements for device support of managed profile functionality
3.12.1. TV App	Added section to clarify TV App requirements for Android Television devices
3.12.1.1. Electronic Program Guide	Added section to clarify EPG requirements for Android Television devices
3.12.1.2. Navigazione	Added section to clarify TV App navigation requirements for Android Television devices
3.12.1.3. TV input app linking	Added section to clarify TV input app linking support requirements for Android Television devices
5.1. Media Codecs	Updates regarding support for core media formats and decoding.
5.1.3. Video Codecs	Changes and additions related to Android Televisions
5.2. Video Encoding	Changes for encoders
5.3. Video Decoding	Changes for decoders, including regarding support for dynamic video resolution, frame rate switching, and more
5.4. Registrazione audio	Additions related to audio capture
5.6. Audio Latency	Update regarding reporting of support for low-latency audio
5.10. Professional Audio	General updates for professional audio support; updates for mobile device (jack) specifications, USB audio host mode, and other updates
5.9. Interfaccia digitale per strumenti musicali (MIDI)	Added new section on optional Musical Instrument Digital Interface (MIDI) support
6.1. Strumenti di sviluppo	Update for drivers supporting Windows 10
7.1.1.3. Screen Density	Updates for screen density, for example related to an Android watch
7.2.3. Navigation Keys	Updated requirements for device implementations that include the Assist action
7.3. Sensors (and subsections)	New requirements for some sensor types
7.3.9. High Fidelity Sensors	New section with requirements for devices supporting high fidelity sensors
7.3.10. Sensore di impronte digitali	New section on requirements related to fingerprint sensors
7.4.2. IEEE 802.11 (Wi-Fi)	Updates regarding support for multicast DNS (mDNS)
7.4.3. Bluetooth	Addition related to Resolvable Private Address (RPA) for Bluetooth Low Energy (BLE)
7.4.4. Near-Field Communications	Additions to requirements for Near-Field Communications (NFC)
7.4.5. Minimum Network Capability	Added requirements for IPv6 support
7.6.3. Adoptable Storage	New section for implementation of adoptable storage
7.7. USB	Requirement related to implementing the AOA specification
7.8.3. Near-Ultrasound	Additions related to near-ultrasound recording, playback, and audio	Relax Near-ultrasound microphone SNR requirement.
8.3. Power-Saving Modes	New section with requirements regarding the App Standby and Doze modes
8.4. Power Consumption Accounting	New section with requirements for tracking hardware component power usage and attributing that power usage to specific applications
9.1. Autorizzazioni	Addition to Permissions requirements
9.7. Kernel Security Features	SE Linux updates
9.8. Privacy	Addition regarding user's consent for access to shared storage over a USB port
9.9. Full-Disk Encryption	Requirements related to full disk encryption
9.10. Verified Boot	Additional requirement for verified boot
9.11. Keys and Credentials	New section of requirements related to keys and credentials
9.12. Data Deletion	New section for "Factory Data Reset"
11. Updatable Software	Requirement related to the system update policy set by the device owner

13. Contact Us

You can join the android-compatibility forum [Resources, 139 ] and ask for clarifications or bring up any issues that you think the document does not cover.

14. Resources

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

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

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

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

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

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

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

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

9. Android 6.0 allowed version strings: http://source.android.com/docs/compatibility/6.0/versions.html

10. Android Developer Settings: http://developer.android.com/reference/android/provider/Settings.html

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

12. Android NDK ABI Management: https://developer.android.com/ndk/guides/abis.html

13. Advanced SIMD architecture: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0388f/Beijfcja.html

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

31. Android Assist APIs: https://developer.android.com/reference/android/app/assist/package-summary.html

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

47. Android Device Owner Provisioning Flow: http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#ACTION_PROVISION_MANAGED_DEVICE

48. Device Owner Provisioning via NFC: /devices/tech/admin/provision.html#device_owner_provisioning_via_nfc

49. Android Profile Owner App: http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#isProfileOwnerApp(java.lang.String)

50. Android Managed Profile Provisioning flow: http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#ACTION_PROVISION_MANAGED_PROFILE

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

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

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

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

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

56. TV App channels: http://developer.android.com/reference/android/media/tv/TvContract.Channels.html

57. Third-party TV inputs: /devices/tv/index.html#third-party_input_example

58. TV inputs: /devices/tv/index.html#tv_inputs

59. TV channel EPG fields: https://developer.android.com/reference/android/media/tv/TvContract.Programs.html

60. TV input app linking: http://developer.android.com/reference/android/media/tv/TvContract.Channels.html#COLUMN_APP_LINK_INTENT_URI

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

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

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

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

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

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

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

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

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

70. Android android.content.pm.PackageManager class and Hardware Features List: http://developer.android.com/reference/android/content/pm/PackageManager.html

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

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

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

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

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

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

77. Android Application Development-Related Settings: http://developer.android.com/reference/android/provider/Settings.html#ACTION_APPLICATION_DEVELOPMENT_SETTINGS

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

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

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

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

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

83. EGL Extension-EGL_ANDROID_RECORDABLE: http://www.khronos.org/registry/egl/extensions/ANDROID/EGL_ANDROID_recordable.txt

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

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

86. Touch Input Configuration: http://source.android.com/docs/core/interaction/input/touch-devices

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

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

89. Android Open Source sensors: http://source.android.com/docs/core/interaction/sensors

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

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

92. Android Open Source composite sensors: /docs/core/interaction/sensors/sensor-types#composite_sensor_type_summary

93. Continuous trigger mode: http://developer.android.com/reference/android/hardware/Sensor.html#TYPE_ACCELEROMETER

95. Android Fingerprint API: https://developer.android.com/reference/android/hardware/fingerprint/package-summary.html

96. Android Fingerprint HAL: /devices/tech/security/authentication/fingerprint-hal.html

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

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

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

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

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

102. NFC Barcode: http://developer.android.com/reference/android/nfc/tech/NfcBarcode.html

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

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

105. Android NFC Sharing Settings: http://developer.android.com/reference/android/provider/Settings.html#ACTION_NFCSHARING_SETTINGS

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

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

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

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

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

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

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

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

114. Camera version support: http://source.android.com/docs/core/camera/versioning

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

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

117. Adoptable storage: http://source.android.com/docs/core/storage/adoptable

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

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

120. USB Battery Charging Specification, Revision 1.2: http://www.usb.org/developers/docs/devclass_docs/BCv1.2_070312.zip

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

122. Wired audio headset: http://source.android.com/docs/core/interaction/accessories/headset/plug-headset-spec

123. Power profile components: http://source.android.com/docs/core/power/values

124. Batterystats: https://developer.android.com/tools/dumpsys#battery

125. Power usage summary: http://developer.android.com/reference/android/content/Intent.html#ACTION_POWER_USAGE_SUMMARY

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

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

128. External Storage reference: http://source.android.com/docs/core/storage/traditional

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

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

131. Secure lock screen reporting: http://developer.android.com/reference/android/app/KeyguardManager.html#isDeviceSecure()

132. Android Open Source Encryption: http://source.android.com/docs/security/features/encryption

133. Android Keystore System: https://developer.android.com/training/articles/keystore.html

134. KeyChain API: https://developer.android.com/reference/android/security/KeyChain.html

135. Keystore API: https://developer.android.com/reference/java/security/KeyStore.html

136. Gatekeeper HAL: http://source.android.com/docs/security/features/authentication/gatekeeper

137. Android Compatibility Program Overview: http://source.android.com/docs/compatibility

138. SystemUpdatePolicy class: http://developer.android.com/reference/android/app/admin/SystemUpdatePolicy.html

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

140. Handling app links: https://developer.android.com/training/app-links/index.html

141. Google Digital Asset Links: https://developers.google.com/digital-asset-links

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