Callback sesi media

Callback sesi media Anda memanggil metode di beberapa API untuk mengontrol pemutar, mengelola fokus audio, serta berkomunikasi dengan sesi media dan layanan browser media. Perhatikan bahwa logika MediaSession yang merespons callback harus konsisten. Perilaku callback tidak boleh bergantung pada identitas pemanggil, yang dapat berupa aktivitas di aplikasi yang sama dengan yang menjalankan MediaSession, atau aplikasi lain dengan MediaController yang tersambung ke MediaSession.

Tabel berikut meringkas bagaimana tugas-tugas ini didistribusikan ke seluruh callback.

Berikut contoh framework untuk callback:

    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)
    }
    

    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);
            }
        };