refactor: let exoplayer handle audio focus

app/src/main/java/com/dkanada/gramophone/service/MusicService.java

@@ -107,9 +107,6 @@ public class MusicService extends Service implements SharedPreferences.OnSharedP
     public static final int PLAY_SONG = 3;
     public static final int PREPARE_NEXT = 4;
     public static final int SET_POSITION = 5;
-    public static final int FOCUS_CHANGE = 6;
-    public static final int DUCK = 7;
-    public static final int UNDUCK = 8;
 
     public static final int SHUFFLE_MODE_NONE = 0;
     public static final int SHUFFLE_MODE_SHUFFLE = 1;
@@ -142,10 +139,8 @@ public class MusicService extends Service implements SharedPreferences.OnSharedP
 
     private boolean notHandledMetaChangedForCurrentTrack;
     private boolean queuesRestored;
-    private boolean pausedByTransientLossOfFocus;
 
     private PlayingNotification playingNotification;
-    private AudioManager audioManager;
     private MediaSessionCompat mediaSession;
     private PowerManager.WakeLock wakeLock;
 
@@ -188,13 +183,6 @@ public class MusicService extends Service implements SharedPreferences.OnSharedP
         }
     };
 
-    private final AudioManager.OnAudioFocusChangeListener audioFocusListener = new AudioManager.OnAudioFocusChangeListener() {
-        @Override
-        public void onAudioFocusChange(final int focusChange) {
-            playerHandler.obtainMessage(FOCUS_CHANGE, focusChange, 0).sendToTarget();
-        }
-    };
-
     private static final long MEDIA_SESSION_ACTIONS = PlaybackStateCompat.ACTION_PLAY
             | PlaybackStateCompat.ACTION_PAUSE
             | PlaybackStateCompat.ACTION_PLAY_PAUSE
@@ -241,14 +229,6 @@ public class MusicService extends Service implements SharedPreferences.OnSharedP
         mediaSession.setActive(true);
     }
 
-    private AudioManager getAudioManager() {
-        if (audioManager == null) {
-            audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
-        }
-
-        return audioManager;
-    }
-
     private void initMediaSession() {
         ComponentName mediaButtonReceiverComponentName = new ComponentName(getApplicationContext(), MediaButtonIntentReceiver.class);
 
@@ -458,7 +438,6 @@ public class MusicService extends Service implements SharedPreferences.OnSharedP
         pause();
         playingNotification.stop();
 
-        getAudioManager().abandonAudioFocus(audioFocusListener);
         stopSelf();
     }
 
@@ -526,10 +505,6 @@ public class MusicService extends Service implements SharedPreferences.OnSharedP
         }
     }
 
-    private boolean requestFocus() {
-        return getAudioManager().requestAudioFocus(audioFocusListener, AudioManager.STREAM_MUSIC, AudioManager.AUDIOFOCUS_GAIN) == AudioManager.AUDIOFOCUS_REQUEST_GRANTED;
-    }
-
     public void initNotification() {
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N && !PreferenceUtil.getInstance(this).getClassicNotification()) {
             playingNotification = new PlayingNotificationNougat();
@@ -805,7 +780,6 @@ public class MusicService extends Service implements SharedPreferences.OnSharedP
     }
 
     public void pause() {
-        pausedByTransientLossOfFocus = false;
         if (playback.isPlaying()) {
             playback.pause();
             notifyChange(STATE_CHANGED);
@@ -814,27 +788,18 @@ public class MusicService extends Service implements SharedPreferences.OnSharedP
 
     public void play() {
         synchronized (this) {
-            if (requestFocus()) {
+            if (!playback.isPlaying()) {
-                if (!playback.isPlaying()) {
+                if (!playback.isReady()) {
-                    if (!playback.isReady()) {
+                    playSongAt(getPosition());
-                        playSongAt(getPosition());
+                } else {
-                    } else {
+                    playback.start();
-                        playback.start();
+                    if (notHandledMetaChangedForCurrentTrack) {
-                        if (notHandledMetaChangedForCurrentTrack) {
+                        handleChangeInternal(META_CHANGED);
-                            handleChangeInternal(META_CHANGED);
+                        notHandledMetaChangedForCurrentTrack = false;
-                            notHandledMetaChangedForCurrentTrack = false;
-                        }
-
-                        notifyChange(STATE_CHANGED);
-
-                        // fixes a bug where the volume would stay ducked
-                        // happens when audio focus GAIN event not sent
-                        playerHandler.removeMessages(DUCK);
-                        playerHandler.sendEmptyMessage(UNDUCK);
                     }
+
+                    notifyChange(STATE_CHANGED);
                 }
-            } else {
-                Toast.makeText(this, getResources().getString(R.string.audio_focus_denied), Toast.LENGTH_SHORT).show();
             }
         }
     }
@@ -1065,7 +1030,6 @@ public class MusicService extends Service implements SharedPreferences.OnSharedP
 
     private static final class PlaybackHandler extends Handler {
         private final WeakReference<MusicService> mService;
-        private int currentDuckVolume = 100;
 
         public PlaybackHandler(final MusicService service, @NonNull final Looper looper) {
             super(looper);
@@ -1080,36 +1044,6 @@ public class MusicService extends Service implements SharedPreferences.OnSharedP
             }
 
             switch (msg.what) {
-                case DUCK:
-                    if (PreferenceUtil.getInstance(service).getAudioDucking()) {
-                        currentDuckVolume -= 5;
-                        if (currentDuckVolume > 20) {
-                            sendEmptyMessageDelayed(DUCK, 10);
-                        } else {
-                            currentDuckVolume = 20;
-                        }
-                    } else {
-                        currentDuckVolume = 100;
-                    }
-
-                    service.playback.setVolume(currentDuckVolume);
-                    break;
-
-                case UNDUCK:
-                    if (PreferenceUtil.getInstance(service).getAudioDucking()) {
-                        currentDuckVolume += 3;
-                        if (currentDuckVolume < 100) {
-                            sendEmptyMessageDelayed(UNDUCK, 10);
-                        } else {
-                            currentDuckVolume = 100;
-                        }
-                    } else {
-                        currentDuckVolume = 100;
-                    }
-
-                    service.playback.setVolume(currentDuckVolume);
-                    break;
-
                 case TRACK_CHANGED:
                     if (service.getRepeatMode() == REPEAT_MODE_NONE && service.isLastTrack()) {
                         service.pause();
@@ -1157,40 +1091,6 @@ public class MusicService extends Service implements SharedPreferences.OnSharedP
                 case PREPARE_NEXT:
                     service.prepareNextImpl();
                     break;
-
-                case FOCUS_CHANGE:
-                    switch (msg.arg1) {
-                        case AudioManager.AUDIOFOCUS_GAIN:
-                            if (!service.isPlaying() && service.pausedByTransientLossOfFocus) {
-                                service.play();
-                                service.pausedByTransientLossOfFocus = false;
-                            }
-                            removeMessages(DUCK);
-                            sendEmptyMessage(UNDUCK);
-                            break;
-
-                        case AudioManager.AUDIOFOCUS_LOSS:
-                            // Lost focus for an unbounded amount of time: stop playback and release media playback
-                            service.pause();
-                            break;
-
-                        case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT:
-                            // Lost focus for a short time, but we have to stop
-                            // playback. We don't release the media playback because playback
-                            // is likely to resume
-                            boolean wasPlaying = service.isPlaying();
-                            service.pause();
-                            service.pausedByTransientLossOfFocus = wasPlaying;
-                            break;
-
-                        case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK:
-                            // Lost focus for a short time, but it's ok to keep playing
-                            // at an attenuated level
-                            removeMessages(UNDUCK);
-                            sendEmptyMessage(DUCK);
-                            break;
-                    }
-                    break;
             }
         }
     }

app/src/main/java/com/dkanada/gramophone/service/playback/LocalPlayer.java

@@ -9,6 +9,8 @@ import com.dkanada.gramophone.R;
 import com.dkanada.gramophone.model.Song;
 import com.dkanada.gramophone.util.MusicUtil;
 import com.dkanada.gramophone.util.PreferenceUtil;
+import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.audio.AudioAttributes;
 import com.google.android.exoplayer2.ExoPlaybackException;
 import com.google.android.exoplayer2.Player;
 import com.google.android.exoplayer2.Player.EventListener;
@@ -82,7 +84,12 @@ public class LocalPlayer implements Playback {
         this.context = context;
 
         MediaSourceFactory mediaSourceFactory = new UnknownMediaSourceFactory(buildDataSourceFactory());
-        exoPlayer = new SimpleExoPlayer.Builder(context).setMediaSourceFactory(mediaSourceFactory).build();
+        AudioAttributes audioAttributes = new AudioAttributes.Builder()
+                .setUsage(C.USAGE_MEDIA)
+                .setContentType(C.CONTENT_TYPE_MUSIC)
+                .build();
+
+        exoPlayer = new SimpleExoPlayer.Builder(context).setMediaSourceFactory(mediaSourceFactory).setAudioAttributes(audioAttributes, true).build();
 
         exoPlayer.addListener(eventListener);
         exoPlayer.prepare();