Add Player.isPlaying and Player.getPlaybackSuppressionReason

The player may suppress playback when waiting for audio focus even if the
state==Player.READY. There is currently no getter or callback to obtain this
piece of information for UI updates or analytics.

Also, it's a important derived state to know whether the playback position is
advancing. Add isPlaying and the corresponding callback to allow retrieving
this information more easily.

Issue:#6203
PiperOrigin-RevId: 268921721

RELEASENOTES.md

@@ -2,6 +2,11 @@
 
 ### 2.10.5 ###
 
+* Add `Player.isPlaying` and `EventListener.onIsPlayingChanged` to check whether
+  the playback position is advancing. This helps to determine if playback is
+  suppressed due to audio focus loss. Also add
+  `Player.getPlaybackSuppressedReason` to determine the reason of the
+  suppression ([#6203](https://github.com/google/ExoPlayer/issues/6203)).
 * Track selection
   * Add `allowAudioMixedChannelCountAdaptiveness` parameter to
     `DefaultTrackSelector` to allow adaptive selections of audio tracks with

extensions/cast/src/main/java/com/google/android/exoplayer2/ext/cast/CastPlayer.java

@@ -327,6 +327,12 @@ public int getPlaybackState() {
     return playbackState;
   }
 
+  @Override
+  @PlaybackSuppressionReason
+  public int getPlaybackSuppressionReason() {
+    return Player.PLAYBACK_SUPPRESSION_REASON_NONE;
+  }
+
   @Override
   @Nullable
   public ExoPlaybackException getPlaybackError() {
@@ -542,6 +548,7 @@ private void updateInternalState() {
       return;
     }
 
+    boolean wasPlaying = playbackState == Player.STATE_READY && playWhenReady;
     int playbackState = fetchPlaybackState(remoteMediaClient);
     boolean playWhenReady = !remoteMediaClient.isPaused();
     if (this.playbackState != playbackState
@@ -552,6 +559,11 @@ private void updateInternalState() {
           new ListenerNotificationTask(
               listener -> listener.onPlayerStateChanged(this.playWhenReady, this.playbackState)));
     }
+    boolean isPlaying = playbackState == Player.STATE_READY && playWhenReady;
+    if (wasPlaying != isPlaying) {
+      notificationsBatch.add(
+          new ListenerNotificationTask(listener -> listener.onIsPlayingChanged(isPlaying)));
+    }
     @RepeatMode int repeatMode = fetchRepeatMode(remoteMediaClient);
     if (this.repeatMode != repeatMode) {
       this.repeatMode = repeatMode;

library/core/src/main/java/com/google/android/exoplayer2/BasePlayer.java

@@ -27,6 +27,13 @@ public BasePlayer() {
     window = new Timeline.Window();
   }
 
+  @Override
+  public final boolean isPlaying() {
+    return getPlaybackState() == Player.STATE_READY
+        && getPlayWhenReady()
+        && getPlaybackSuppressionReason() == PLAYBACK_SUPPRESSION_REASON_NONE;
+  }
+
   @Override
   public final void seekToDefaultPosition() {
     seekToDefaultPosition(getCurrentWindowIndex());

library/core/src/main/java/com/google/android/exoplayer2/ExoPlayerImpl.java

@@ -64,8 +64,8 @@
 
   private MediaSource mediaSource;
   private boolean playWhenReady;
-  private boolean internalPlayWhenReady;
-  private @RepeatMode int repeatMode;
+  @PlaybackSuppressionReason private int playbackSuppressionReason;
+  @RepeatMode private int repeatMode;
   private boolean shuffleModeEnabled;
   private int pendingOperationAcks;
   private boolean hasPendingPrepare;
@@ -119,6 +119,7 @@ public ExoPlayerImpl(
     period = new Timeline.Period();
     playbackParameters = PlaybackParameters.DEFAULT;
     seekParameters = SeekParameters.DEFAULT;
+    playbackSuppressionReason = PLAYBACK_SUPPRESSION_REASON_NONE;
     eventHandler =
         new Handler(looper) {
           @Override
@@ -197,8 +198,14 @@ public int getPlaybackState() {
     return playbackInfo.playbackState;
   }
 
+  @PlaybackSuppressionReason
+  public int getPlaybackSuppressionReason() {
+    return playbackSuppressionReason;
+  }
+
   @Override
-  public @Nullable ExoPlaybackException getPlaybackError() {
+  @Nullable
+  public ExoPlaybackException getPlaybackError() {
     return playbackError;
   }
 
@@ -239,19 +246,35 @@ public void prepare(MediaSource mediaSource, boolean resetPosition, boolean rese
 
   @Override
   public void setPlayWhenReady(boolean playWhenReady) {
-    setPlayWhenReady(playWhenReady, /* suppressPlayback= */ false);
+    setPlayWhenReady(playWhenReady, PLAYBACK_SUPPRESSION_REASON_NONE);
   }
 
-  public void setPlayWhenReady(boolean playWhenReady, boolean suppressPlayback) {
-    boolean internalPlayWhenReady = playWhenReady && !suppressPlayback;
-    if (this.internalPlayWhenReady != internalPlayWhenReady) {
-      this.internalPlayWhenReady = internalPlayWhenReady;
+  public void setPlayWhenReady(
+      boolean playWhenReady, @PlaybackSuppressionReason int playbackSuppressionReason) {
+    boolean oldIsPlaying = isPlaying();
+    boolean oldInternalPlayWhenReady =
+        this.playWhenReady && this.playbackSuppressionReason == PLAYBACK_SUPPRESSION_REASON_NONE;
+    boolean internalPlayWhenReady =
+        playWhenReady && playbackSuppressionReason == PLAYBACK_SUPPRESSION_REASON_NONE;
+    if (oldInternalPlayWhenReady != internalPlayWhenReady) {
       internalPlayer.setPlayWhenReady(internalPlayWhenReady);
     }
-    if (this.playWhenReady != playWhenReady) {
-      this.playWhenReady = playWhenReady;
+    boolean playWhenReadyChanged = this.playWhenReady != playWhenReady;
+    this.playWhenReady = playWhenReady;
+    this.playbackSuppressionReason = playbackSuppressionReason;
+    boolean isPlaying = isPlaying();
+    boolean isPlayingChanged = oldIsPlaying != isPlaying;
+    if (playWhenReadyChanged || isPlayingChanged) {
       int playbackState = playbackInfo.playbackState;
-      notifyListeners(listener -> listener.onPlayerStateChanged(playWhenReady, playbackState));
+      notifyListeners(
+          listener -> {
+            if (playWhenReadyChanged) {
+              listener.onPlayerStateChanged(playWhenReady, playbackState);
+            }
+            if (isPlayingChanged) {
+              listener.onIsPlayingChanged(isPlaying);
+            }
+          });
     }
   }
 
@@ -697,9 +720,11 @@ private void updatePlaybackInfo(
       @Player.DiscontinuityReason int positionDiscontinuityReason,
       @Player.TimelineChangeReason int timelineChangeReason,
       boolean seekProcessed) {
+    boolean previousIsPlaying = isPlaying();
     // Assign playback info immediately such that all getters return the right values.
     PlaybackInfo previousPlaybackInfo = this.playbackInfo;
     this.playbackInfo = playbackInfo;
+    boolean isPlaying = isPlaying();
     notifyListeners(
         new PlaybackInfoUpdate(
             playbackInfo,
@@ -710,7 +735,8 @@ private void updatePlaybackInfo(
             positionDiscontinuityReason,
             timelineChangeReason,
             seekProcessed,
-            playWhenReady));
+            playWhenReady,
+            /* isPlayingChanged= */ previousIsPlaying != isPlaying));
   }
 
   private void notifyListeners(ListenerInvocation listenerInvocation) {
@@ -755,17 +781,19 @@ private static final class PlaybackInfoUpdate implements Runnable {
     private final boolean isLoadingChanged;
     private final boolean trackSelectorResultChanged;
     private final boolean playWhenReady;
+    private final boolean isPlayingChanged;
 
     public PlaybackInfoUpdate(
         PlaybackInfo playbackInfo,
         PlaybackInfo previousPlaybackInfo,
         CopyOnWriteArrayList<ListenerHolder> listeners,
         TrackSelector trackSelector,
         boolean positionDiscontinuity,
-        @Player.DiscontinuityReason int positionDiscontinuityReason,
-        @Player.TimelineChangeReason int timelineChangeReason,
+        @DiscontinuityReason int positionDiscontinuityReason,
+        @TimelineChangeReason int timelineChangeReason,
         boolean seekProcessed,
-        boolean playWhenReady) {
+        boolean playWhenReady,
+        boolean isPlayingChanged) {
       this.playbackInfo = playbackInfo;
       this.listenerSnapshot = new CopyOnWriteArrayList<>(listeners);
       this.trackSelector = trackSelector;
@@ -774,6 +802,7 @@ public PlaybackInfoUpdate(
       this.timelineChangeReason = timelineChangeReason;
       this.seekProcessed = seekProcessed;
       this.playWhenReady = playWhenReady;
+      this.isPlayingChanged = isPlayingChanged;
       playbackStateChanged = previousPlaybackInfo.playbackState != playbackInfo.playbackState;
       timelineOrManifestChanged =
           previousPlaybackInfo.timeline != playbackInfo.timeline
@@ -813,6 +842,12 @@ public void run() {
             listenerSnapshot,
             listener -> listener.onPlayerStateChanged(playWhenReady, playbackInfo.playbackState));
       }
+      if (isPlayingChanged) {
+        invokeAll(
+            listenerSnapshot,
+            listener ->
+                listener.onIsPlayingChanged(playbackInfo.playbackState == Player.STATE_READY));
+      }
       if (seekProcessed) {
         invokeAll(listenerSnapshot, EventListener::onSeekProcessed);
       }

library/core/src/main/java/com/google/android/exoplayer2/Player.java

@@ -365,6 +365,13 @@ default void onLoadingChanged(boolean isLoading) {}
      */
     default void onPlayerStateChanged(boolean playWhenReady, int playbackState) {}
 
+    /**
+     * Called when the value of {@link #isPlaying()} changes.
+     *
+     * @param isPlaying Whether the player is playing.
+     */
+    default void onIsPlayingChanged(boolean isPlaying) {}
+
     /**
      * Called when the value of {@link #getRepeatMode()} changes.
      *
@@ -462,6 +469,20 @@ public void onTimelineChanged(Timeline timeline, @Nullable Object manifest) {
    */
   int STATE_ENDED = 4;
 
+  /**
+   * Reason why playback is suppressed even if {@link #getPlaybackState()} is {@link #STATE_READY}
+   * and {@link #getPlayWhenReady()} is {@code true}. One of {@link
+   * #PLAYBACK_SUPPRESSION_REASON_NONE} or {@link #PLAYBACK_SUPPRESSION_REASON_AUDIO_FOCUS_LOSS}.
+   */
+  @Documented
+  @Retention(RetentionPolicy.SOURCE)
+  @IntDef({PLAYBACK_SUPPRESSION_REASON_NONE, PLAYBACK_SUPPRESSION_REASON_AUDIO_FOCUS_LOSS})
+  @interface PlaybackSuppressionReason {}
+  /** Playback is not suppressed. */
+  int PLAYBACK_SUPPRESSION_REASON_NONE = 0;
+  /** Playback is suppressed because audio focus is lost or can't be acquired. */
+  int PLAYBACK_SUPPRESSION_REASON_AUDIO_FOCUS_LOSS = 1;
+
   /**
    * Repeat modes for playback. One of {@link #REPEAT_MODE_OFF}, {@link #REPEAT_MODE_ONE} or {@link
    * #REPEAT_MODE_ALL}.
@@ -587,12 +608,42 @@ public void onTimelineChanged(Timeline timeline, @Nullable Object manifest) {
    */
   int getPlaybackState();
 
+  /**
+   * Returns reason why playback is suppressed even if {@link #getPlaybackState()} is {@link
+   * #STATE_READY} and {@link #getPlayWhenReady()} is {@code true}.
+   *
+   * <p>Note that {@link #PLAYBACK_SUPPRESSION_REASON_NONE} indicates that playback is not
+   * suppressed.
+   *
+   * @return The current {@link PlaybackSuppressionReason}.
+   */
+  @PlaybackSuppressionReason
+  int getPlaybackSuppressionReason();
+
+  /**
+   * Returns whether the player is playing, i.e. {@link #getContentPosition()} is advancing.
+   *
+   * <p>If {@code false}, then at least one of the following is true:
+   *
+   * <ul>
+   *   <li>The {@link #getPlaybackState() playback state} is not {@link #STATE_READY ready}.
+   *   <li>There is no {@link #getPlayWhenReady() intention to play}.
+   *   <li>Playback is {@link #getPlaybackSuppressionReason() suppressed for other reasons}.
+   * </ul>
+   *
+   * @return Whether the player is playing.
+   */
+  boolean isPlaying();
+
   /**
    * Returns the error that caused playback to fail. This is the same error that will have been
    * reported via {@link Player.EventListener#onPlayerError(ExoPlaybackException)} at the time of
    * failure. It can be queried using this method until {@code stop(true)} is called or the player
    * is re-prepared.
    *
+   * <p>Note that this method will always return {@code null} if {@link #getPlaybackState()} is not
+   * {@link #STATE_IDLE}.
+   *
    * @return The error, or {@code null}.
    */
   @Nullable

library/core/src/main/java/com/google/android/exoplayer2/SimpleExoPlayer.java

@@ -878,8 +878,15 @@ public int getPlaybackState() {
     return player.getPlaybackState();
   }
 
+  @PlaybackSuppressionReason
+  public int getPlaybackSuppressionReason() {
+    verifyApplicationThread();
+    return player.getPlaybackSuppressionReason();
+  }
+
   @Override
-  public @Nullable ExoPlaybackException getPlaybackError() {
+  @Nullable
+  public ExoPlaybackException getPlaybackError() {
     verifyApplicationThread();
     return player.getPlaybackError();
   }
@@ -1221,9 +1228,13 @@ private void sendVolumeToRenderers() {
 
   private void updatePlayWhenReady(
       boolean playWhenReady, @AudioFocusManager.PlayerCommand int playerCommand) {
+    int playbackSuppressionReason =
+        playerCommand == AudioFocusManager.PLAYER_COMMAND_PLAY_WHEN_READY
+            ? Player.PLAYBACK_SUPPRESSION_REASON_NONE
+            : Player.PLAYBACK_SUPPRESSION_REASON_AUDIO_FOCUS_LOSS;
     player.setPlayWhenReady(
         playWhenReady && playerCommand != AudioFocusManager.PLAYER_COMMAND_DO_NOT_PLAY,
-        playerCommand != AudioFocusManager.PLAYER_COMMAND_PLAY_WHEN_READY);
+        playbackSuppressionReason);
   }
 
   private void verifyApplicationThread() {

testutils_robolectric/src/main/java/com/google/android/exoplayer2/testutil/StubExoPlayer.java

@@ -79,6 +79,12 @@ public int getPlaybackState() {
     throw new UnsupportedOperationException();
   }
 
+  @Override
+  @PlaybackSuppressionReason
+  public int getPlaybackSuppressionReason() {
+    throw new UnsupportedOperationException();
+  }
+
   @Override
   public ExoPlaybackException getPlaybackError() {
     throw new UnsupportedOperationException();