use exoplayer design for player callbacks

app/src/main/java/com/dkanada/gramophone/helper/MusicPlayerRemote.java

@@ -137,7 +137,7 @@ public class MusicPlayerRemote {
     }
 
     public static boolean isBuffering() {
-        return musicService != null && musicService.isBuffering();
+        return musicService != null && musicService.isLoading();
     }
 
     public static void resumePlaying() {

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

@@ -37,28 +37,30 @@ public class MultiPlayer implements Playback {
     private PlaybackCallbacks callbacks;
 
     private final ExoPlayer.EventListener eventListener = new ExoPlayer.EventListener() {
-
         @Override
-        public void onPlayerStateChanged(boolean playWhenReady, int playbackState) {
+        public void onIsLoadingChanged(boolean isLoading) {
-            Log.i(TAG, String.format("onPlayerStateChanged: %b %d", playWhenReady, playbackState));
+            Log.i(TAG, String.format("onIsLoadingChanged: %b", isLoading));
-            if (callbacks != null) {
-                callbacks.onPlayerStateChanged(playWhenReady, playbackState);
-            }
         }
 
         @Override
-        public void onPositionDiscontinuity(int reason) {
+        public void onPlayWhenReadyChanged(boolean playWhenReady, int reason) {
-            Log.i(TAG, String.format("onPositionDiscontinuity: %d", reason));
+            Log.i(TAG, String.format("onPlayWhenReadyChanged: %b %d", playWhenReady, reason));
-            int windowIndex = exoPlayer.getCurrentWindowIndex();
+            if (callbacks != null) callbacks.onReadyChanged(playWhenReady, reason);
+        }
 
-            if (windowIndex == 1) {
+        @Override
+        public void onPlaybackStateChanged(int state) {
+            Log.i(TAG, String.format("onPlaybackStateChanged: %d", state));
+            if (callbacks != null) callbacks.onStateChanged(state);
+        }
+
+        @Override
+        public void onMediaItemTransition(MediaItem mediaItem, int reason) {
+            Log.i(TAG, String.format("onMediaItemTransition: %s %d", mediaItem, reason));
+
+            if (exoPlayer.getMediaItemCount() > 1) {
                 exoPlayer.removeMediaItem(0);
-                if (exoPlayer.isPlaying()) {
+                callbacks.onTrackChanged(reason);
-                    // there are still songs left in the queue
-                    callbacks.onTrackWentToNext();
-                } else {
-                    callbacks.onTrackEnded();
-                }
             }
         }
 
@@ -88,6 +90,13 @@ public class MultiPlayer implements Playback {
 
     @Override
     public void setDataSource(Song song) {
+        String uri = MusicUtil.getSongFileUri(song);
+        MediaItem mediaItem = exoPlayer.getCurrentMediaItem();
+
+        if (mediaItem != null && mediaItem.playbackProperties.uri.toString().equals(uri)) {
+            return;
+        }
+
         exoPlayer.clearMediaItems();
         appendDataSource(MusicUtil.getSongFileUri(song));
         exoPlayer.seekTo(0, 0);
@@ -127,7 +136,7 @@ public class MultiPlayer implements Playback {
 
     @Override
     public boolean isReady() {
-        return true;
+        return exoPlayer.getPlayWhenReady();
     }
 
     @Override
@@ -136,7 +145,7 @@ public class MultiPlayer implements Playback {
     }
 
     @Override
-    public boolean isBuffering() {
+    public boolean isLoading() {
         return exoPlayer.getPlaybackState() == Player.STATE_BUFFERING;
     }
 

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

@@ -51,7 +51,6 @@ import com.dkanada.gramophone.util.Util;
 import com.dkanada.gramophone.widgets.AppWidgetAlbum;
 import com.dkanada.gramophone.widgets.AppWidgetCard;
 import com.dkanada.gramophone.widgets.AppWidgetClassic;
-import com.google.android.exoplayer2.Player;
 
 import org.jellyfin.apiclient.interaction.EmptyResponse;
 import org.jellyfin.apiclient.interaction.Response;
@@ -69,6 +68,9 @@ import java.util.concurrent.Future;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
 
+import static com.google.android.exoplayer2.Player.MEDIA_ITEM_TRANSITION_REASON_AUTO;
+import static com.google.android.exoplayer2.Player.PLAY_WHEN_READY_CHANGE_REASON_END_OF_MEDIA_ITEM;
+
 public class MusicService extends Service implements SharedPreferences.OnSharedPreferenceChangeListener, Playback.PlaybackCallbacks {
     public static final String PACKAGE_NAME = "com.dkanada.gramophone";
 
@@ -483,8 +485,8 @@ public class MusicService extends Service implements SharedPreferences.OnSharedP
         return playback != null && playback.isPlaying();
     }
 
-    public boolean isBuffering() {
+    public boolean isLoading() {
-        return playback != null && playback.isBuffering();
+        return playback != null && playback.isLoading();
     }
 
     public int getPosition() {
@@ -1036,26 +1038,29 @@ public class MusicService extends Service implements SharedPreferences.OnSharedP
     }
 
     @Override
-    public void onPlayerStateChanged(boolean playWhenReady, int playbackState) {
+    public void onStateChanged(int state) {
         notifyChange(STATE_CHANGED);
-        if (playWhenReady && playbackState == Player.STATE_READY) {
+    }
+
+    @Override
+    public void onReadyChanged(boolean ready, int reason) {
+        notifyChange(STATE_CHANGED);
+
+        if (ready) {
             progressHandler.sendEmptyMessage(TRACK_STARTED);
             prepareNext();
+        } else if (reason == PLAY_WHEN_READY_CHANGE_REASON_END_OF_MEDIA_ITEM) {
+            progressHandler.sendEmptyMessage(TRACK_ENDED);
+            acquireWakeLock(30000);
         }
     }
 
     @Override
-    public void onTrackWentToNext() {
+    public void onTrackChanged(int reason) {
-        playerHandler.sendEmptyMessage(TRACK_CHANGED);
+        if (reason == MEDIA_ITEM_TRANSITION_REASON_AUTO) {
-        progressHandler.sendEmptyMessage(TRACK_CHANGED);
+            playerHandler.sendEmptyMessage(TRACK_CHANGED);
-    }
+            progressHandler.sendEmptyMessage(TRACK_CHANGED);
-
+        }
-    @Override
-    public void onTrackEnded() {
-        playerHandler.sendEmptyMessage(TRACK_ENDED);
-        progressHandler.sendEmptyMessage(TRACK_ENDED);
-
-        acquireWakeLock(30000);
     }
 
     private static final class PlaybackHandler extends Handler {
@@ -1292,7 +1297,7 @@ public class MusicService extends Service implements SharedPreferences.OnSharedP
             info.setPositionTicks(progress * 10000);
 
             if (task != null) task.cancel(true);
-            executorService.shutdownNow();
+            if (executorService != null) executorService.shutdownNow();
         }
     }
 }

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

@@ -13,7 +13,7 @@ public interface Playback {
 
     boolean isPlaying();
 
-    boolean isBuffering();
+    boolean isLoading();
 
     void start();
 
@@ -32,10 +32,10 @@ public interface Playback {
     int getVolume();
 
     interface PlaybackCallbacks {
-        void onPlayerStateChanged(boolean playWhenReady, int playbackState);
+        void onStateChanged(int state);
 
-        void onTrackWentToNext();
+        void onReadyChanged(boolean ready, int reason);
 
-        void onTrackEnded();
+        void onTrackChanged(int reason);
     }
 }