Ihre Mediensitzungs-Callbacks rufen Methoden in mehreren APIs auf, um den Player zu steuern, den Audiofokus zu verwalten,
und mit dem Mediensitzungs- und Medienbrowserdienst kommunizieren. Das Feld
Die MediaSession
-Logik, die auf Callbacks reagiert, muss einheitlich sein. Das Verhalten
des Callbacks darf nicht von der Identität des Aufrufers abhängen.
eine Aktivität in derselben App, in der MediaSession
oder eine andere App mit einem
MediaController
mit MediaSession
verbunden.
In der folgenden Tabelle wird zusammengefasst, wie diese Aufgaben auf Callbacks verteilt sind.
onPlay() | onPause() | onStop(). | |
Audiofokus | requestFocus() übergibt OnAudioFocusChangeListener .Rufe zuerst requestFocus() auf. Fahre nur fort, wenn der Fokus aktiviert ist.
|
abandonAudioFocus()
|
|
Dienst | startService()
|
stopSelf()
|
|
Mediensitzung | setActive(true)
- Metadaten und Status aktualisieren |
- Metadaten und Status aktualisieren | setActive(false)
- Metadaten und Status aktualisieren |
Player-Implementierung | Player starten | Player pausieren | Player anhalten |
Lauter werden | BroadcastReceiver registrieren
|
BroadcastReceiver abmelden
|
|
Benachrichtigungen | startForeground(notification)
|
stopForeground(false)
|
stopForeground(false)
|
Hier ist ein Beispiel-Framework für den Callback:
Kotlin
private val intentFilter = IntentFilter(ACTION_AUDIO_BECOMING_NOISY) // Defined elsewhere... private lateinit var afChangeListener: AudioManager.OnAudioFocusChangeListener private val myNoisyAudioStreamReceiver = BecomingNoisyReceiver() private lateinit var myPlayerNotification: MediaStyleNotification private lateinit var mediaSession: MediaSessionCompat private lateinit var service: MediaBrowserService private lateinit var player: SomeKindOfPlayer private lateinit var audioFocusRequest: AudioFocusRequest private val callback = object: MediaSessionCompat.Callback() { override fun onPlay() { val am = context.getSystemService(Context.AUDIO_SERVICE) as AudioManager // Request audio focus for playback, this registers the afChangeListener audioFocusRequest = AudioFocusRequest.Builder(AudioManager.AUDIOFOCUS_GAIN).run { setOnAudioFocusChangeListener(afChangeListener) setAudioAttributes(AudioAttributes.Builder().run { setContentType(AudioAttributes.CONTENT_TYPE_MUSIC) build() }) build() } val result = am.requestAudioFocus(audioFocusRequest) if (result == AudioManager.AUDIOFOCUS_REQUEST_GRANTED) { // Start the service startService(Intent(context, MediaBrowserService::class.java)) // Set the session active (and update metadata and state) mediaSession.isActive = true // start the player (custom call) player.start() // Register BECOME_NOISY BroadcastReceiver registerReceiver(myNoisyAudioStreamReceiver, intentFilter) // Put the service in the foreground, post notification service.startForeground(id, myPlayerNotification) } } public override fun onStop() { val am = context.getSystemService(Context.AUDIO_SERVICE) as AudioManager // Abandon audio focus am.abandonAudioFocusRequest(audioFocusRequest) unregisterReceiver(myNoisyAudioStreamReceiver) // Stop the service service.stopSelf() // Set the session inactive (and update metadata and state) mediaSession.isActive = false // stop the player (custom call) player.stop() // Take the service out of the foreground service.stopForeground(false) } public override fun onPause() { val am = context.getSystemService(Context.AUDIO_SERVICE) as AudioManager // Update metadata and state // pause the player (custom call) player.pause() // unregister BECOME_NOISY BroadcastReceiver unregisterReceiver(myNoisyAudioStreamReceiver) // Take the service out of the foreground, retain the notification service.stopForeground(false) } }
Java
private IntentFilter intentFilter = new IntentFilter(AudioManager.ACTION_AUDIO_BECOMING_NOISY); // Defined elsewhere... private AudioManager.OnAudioFocusChangeListener afChangeListener; private BecomingNoisyReceiver myNoisyAudioStreamReceiver = new BecomingNoisyReceiver(); private MediaStyleNotification myPlayerNotification; private MediaSessionCompat mediaSession; private MediaBrowserService service; private SomeKindOfPlayer player; private AudioFocusRequest audioFocusRequest; MediaSessionCompat.Callback callback = new MediaSessionCompat.Callback() { @Override public void onPlay() { AudioManager am = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE); // Request audio focus for playback, this registers the afChangeListener AudioAttributes attrs = new AudioAttributes.Builder() .setContentType(AudioAttributes.CONTENT_TYPE_MUSIC) .build(); audioFocusRequest = new AudioFocusRequest.Builder(AudioManager.AUDIOFOCUS_GAIN) .setOnAudioFocusChangeListener(afChangeListener) .setAudioAttributes(attrs) .build(); int result = am.requestAudioFocus(audioFocusRequest); if (result == AudioManager.AUDIOFOCUS_REQUEST_GRANTED) { // Start the service startService(new Intent(context, MediaBrowserService.class)); // Set the session active (and update metadata and state) mediaSession.setActive(true); // start the player (custom call) player.start(); // Register BECOME_NOISY BroadcastReceiver registerReceiver(myNoisyAudioStreamReceiver, intentFilter); // Put the service in the foreground, post notification service.startForeground(id, myPlayerNotification); } } @Override public void onStop() { AudioManager am = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE); // Abandon audio focus am.abandonAudioFocusRequest(audioFocusRequest); unregisterReceiver(myNoisyAudioStreamReceiver); // Stop the service service.stopSelf(); // Set the session inactive (and update metadata and state) mediaSession.setActive(false); // stop the player (custom call) player.stop(); // Take the service out of the foreground service.stopForeground(false); } @Override public void onPause() { AudioManager am = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE); // Update metadata and state // pause the player (custom call) player.pause(); // unregister BECOME_NOISY BroadcastReceiver unregisterReceiver(myNoisyAudioStreamReceiver); // Take the service out of the foreground, retain the notification service.stopForeground(false); } };