Implement getCurrentTracks in MediaController

After this change the current tracks are sent to the controller as part of
`PlayerInfo` and call `Listener.onTracksChanged()` in case of a change in tracks.

PiperOrigin-RevId: 461578695

libraries/session/src/main/java/androidx/media3/session/MediaController.java

@@ -1677,7 +1677,8 @@ public class MediaController implements Player {
 
   @Override
   public Tracks getCurrentTracks() {
-    return Tracks.EMPTY; // TODO(b/178486745)
+    verifyApplicationThread();
+    return isConnected() ? impl.getCurrentTracks() : Tracks.EMPTY;
   }
 
   @Override
@@ -2010,6 +2011,8 @@ public class MediaController implements Player {
 
     Commands getAvailableCommands();
 
+    Tracks getCurrentTracks();
+
     TrackSelectionParameters getTrackSelectionParameters();
 
     void setTrackSelectionParameters(TrackSelectionParameters parameters);

libraries/session/src/main/java/androidx/media3/session/MediaControllerImplBase.java

@@ -57,6 +57,7 @@ import static androidx.media3.common.Player.EVENT_SEEK_BACK_INCREMENT_CHANGED;
 import static androidx.media3.common.Player.EVENT_SEEK_FORWARD_INCREMENT_CHANGED;
 import static androidx.media3.common.Player.EVENT_SHUFFLE_MODE_ENABLED_CHANGED;
 import static androidx.media3.common.Player.EVENT_TIMELINE_CHANGED;
+import static androidx.media3.common.Player.EVENT_TRACKS_CHANGED;
 import static androidx.media3.common.Player.EVENT_TRACK_SELECTION_PARAMETERS_CHANGED;
 import static androidx.media3.common.Player.MEDIA_ITEM_TRANSITION_REASON_PLAYLIST_CHANGED;
 import static androidx.media3.common.Player.MEDIA_ITEM_TRANSITION_REASON_REPEAT;
@@ -132,6 +133,7 @@ import androidx.media3.common.Timeline.Period;
 import androidx.media3.common.Timeline.RemotableTimeline;
 import androidx.media3.common.Timeline.Window;
 import androidx.media3.common.TrackSelectionParameters;
+import androidx.media3.common.Tracks;
 import androidx.media3.common.VideoSize;
 import androidx.media3.common.text.CueGroup;
 import androidx.media3.common.util.BundleableUtil;
@@ -1766,6 +1768,11 @@ import org.checkerframework.checker.nullness.qual.NonNull;
     return intersectedPlayerCommands;
   }
 
+  @Override
+  public Tracks getCurrentTracks() {
+    return playerInfo.currentTracks;
+  }
+
   @Override
   public TrackSelectionParameters getTrackSelectionParameters() {
     return playerInfo.trackSelectionParameters;
@@ -2388,6 +2395,10 @@ import org.checkerframework.checker.nullness.qual.NonNull;
               listener.onMediaItemTransition(
                   currentMediaItem, playerInfo.mediaItemTransitionReason));
     }
+    if (!Util.areEqual(oldPlayerInfo.currentTracks, newPlayerInfo.currentTracks)) {
+      listeners.queueEvent(
+          EVENT_TRACKS_CHANGED, listener -> listener.onTracksChanged(newPlayerInfo.currentTracks));
+    }
     if (!Util.areEqual(oldPlayerInfo.playbackParameters, playerInfo.playbackParameters)) {
       listeners.queueEvent(
           EVENT_PLAYBACK_PARAMETERS_CHANGED,

libraries/session/src/main/java/androidx/media3/session/MediaControllerImplLegacy.java

@@ -83,6 +83,7 @@ import androidx.media3.common.Rating;
 import androidx.media3.common.Timeline;
 import androidx.media3.common.Timeline.Window;
 import androidx.media3.common.TrackSelectionParameters;
+import androidx.media3.common.Tracks;
 import androidx.media3.common.VideoSize;
 import androidx.media3.common.text.CueGroup;
 import androidx.media3.common.util.Clock;
@@ -1184,6 +1185,11 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
     return controllerInfo.availablePlayerCommands;
   }
 
+  @Override
+  public Tracks getCurrentTracks() {
+    return Tracks.EMPTY;
+  }
+
   @Override
   public TrackSelectionParameters getTrackSelectionParameters() {
     return TrackSelectionParameters.DEFAULT_WITHOUT_CONTEXT;
@@ -2102,6 +2108,7 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
             seekBackIncrementMs,
             seekForwardIncrementMs,
             /* maxSeekToPreviousPositionMs= */ 0L,
+            /* currentTracks= */ Tracks.EMPTY,
             /* parameters= */ TrackSelectionParameters.DEFAULT_WITHOUT_CONTEXT);
 
     return new ControllerInfo(

libraries/session/src/main/java/androidx/media3/session/MediaSession.java

@@ -51,6 +51,7 @@ import androidx.media3.common.Player.RepeatMode;
 import androidx.media3.common.Rating;
 import androidx.media3.common.Timeline;
 import androidx.media3.common.TrackSelectionParameters;
+import androidx.media3.common.Tracks;
 import androidx.media3.common.VideoSize;
 import androidx.media3.common.util.UnstableApi;
 import androidx.media3.common.util.Util;
@@ -1123,6 +1124,8 @@ public class MediaSession {
 
     default void onIsLoadingChanged(int seq, boolean isLoading) throws RemoteException {}
 
+    default void onTracksChanged(int seq, Tracks tracks) throws RemoteException {}
+
     default void onTrackSelectionParametersChanged(int seq, TrackSelectionParameters parameters)
         throws RemoteException {}
 

libraries/session/src/main/java/androidx/media3/session/MediaSessionImpl.java

@@ -61,6 +61,7 @@ import androidx.media3.common.Player.RepeatMode;
 import androidx.media3.common.Rating;
 import androidx.media3.common.Timeline;
 import androidx.media3.common.TrackSelectionParameters;
+import androidx.media3.common.Tracks;
 import androidx.media3.common.VideoSize;
 import androidx.media3.common.text.CueGroup;
 import androidx.media3.common.util.Log;
@@ -401,13 +402,13 @@ import org.checkerframework.checker.initialization.qual.Initialized;
             .onPlayerInfoChanged(
                 seq,
                 playerInfo,
-                !sessionStub
+                /* excludeMediaItems= */ !sessionStub
                     .getConnectedControllersManager()
                     .isPlayerCommandAvailable(controller, Player.COMMAND_GET_TIMELINE),
-                !sessionStub
+                /* excludeMediaItemsMetadata= */ !sessionStub
                     .getConnectedControllersManager()
                     .isPlayerCommandAvailable(controller, Player.COMMAND_GET_MEDIA_ITEMS_METADATA),
-                !sessionStub
+                /* excludeCues= */ !sessionStub
                     .getConnectedControllersManager()
                     .isPlayerCommandAvailable(controller, Player.COMMAND_GET_TEXT),
                 excludeTimeline);
@@ -1087,6 +1088,23 @@ import org.checkerframework.checker.initialization.qual.Initialized;
           (callback, seq) -> callback.onDeviceInfoChanged(seq, session.playerInfo.deviceInfo));
     }
 
+    @Override
+    public void onTracksChanged(Tracks tracks) {
+      @Nullable MediaSessionImpl session = getSession();
+      if (session == null) {
+        return;
+      }
+      session.verifyApplicationThread();
+      @Nullable PlayerWrapper player = this.player.get();
+      if (player == null) {
+        return;
+      }
+      session.playerInfo = session.playerInfo.copyWithCurrentTracks(tracks);
+      session.onPlayerInfoChangedHandler.sendPlayerInfoChangedMessage(/* excludeTimeline= */ true);
+      session.dispatchRemoteControllerTaskWithoutReturn(
+          (callback, seq) -> callback.onTracksChanged(seq, tracks));
+    }
+
     @Override
     public void onTrackSelectionParametersChanged(TrackSelectionParameters parameters) {
       @Nullable MediaSessionImpl session = getSession();

libraries/session/src/main/java/androidx/media3/session/PlayerInfo.java

@@ -42,6 +42,7 @@ import androidx.media3.common.Player.State;
 import androidx.media3.common.Timeline;
 import androidx.media3.common.Timeline.Window;
 import androidx.media3.common.TrackSelectionParameters;
+import androidx.media3.common.Tracks;
 import androidx.media3.common.VideoSize;
 import androidx.media3.common.text.CueGroup;
 import androidx.media3.common.util.Assertions;
@@ -90,6 +91,7 @@ import java.lang.annotation.Target;
     private long seekBackIncrementMs;
     private long seekForwardIncrementMs;
     private long maxSeekToPreviousPositionMs;
+    private Tracks currentTracks;
     private TrackSelectionParameters trackSelectionParameters;
 
     public Builder(PlayerInfo playerInfo) {
@@ -121,6 +123,7 @@ import java.lang.annotation.Target;
       seekBackIncrementMs = playerInfo.seekBackIncrementMs;
       seekForwardIncrementMs = playerInfo.seekForwardIncrementMs;
       maxSeekToPreviousPositionMs = playerInfo.maxSeekToPreviousPositionMs;
+      currentTracks = playerInfo.currentTracks;
       trackSelectionParameters = playerInfo.trackSelectionParameters;
     }
 
@@ -267,6 +270,11 @@ import java.lang.annotation.Target;
       return this;
     }
 
+    public Builder setCurrentTracks(Tracks tracks) {
+      currentTracks = tracks;
+      return this;
+    }
+
     public Builder setTrackSelectionParameters(TrackSelectionParameters parameters) {
       trackSelectionParameters = parameters;
       return this;
@@ -305,6 +313,7 @@ import java.lang.annotation.Target;
           seekBackIncrementMs,
           seekForwardIncrementMs,
           maxSeekToPreviousPositionMs,
+          currentTracks,
           trackSelectionParameters);
     }
   }
@@ -350,6 +359,7 @@ import java.lang.annotation.Target;
           /* seekBackIncrementMs= */ 0,
           /* seekForwardIncrementMs= */ 0,
           /* maxSeekToPreviousPositionMs= */ 0,
+          /* currentTracks= */ Tracks.EMPTY,
           TrackSelectionParameters.DEFAULT_WITHOUT_CONTEXT);
 
   @Nullable public final PlaybackException playerError;
@@ -408,6 +418,8 @@ import java.lang.annotation.Target;
 
   public final long maxSeekToPreviousPositionMs;
 
+  public final Tracks currentTracks;
+
   public final TrackSelectionParameters trackSelectionParameters;
 
   @CheckResult
@@ -578,6 +590,10 @@ import java.lang.annotation.Target;
     return new Builder(this).setMaxSeekToPreviousPositionMs(maxSeekToPreviousPositionMs).build();
   }
 
+  public PlayerInfo copyWithCurrentTracks(Tracks tracks) {
+    return new Builder(this).setCurrentTracks(tracks).build();
+  }
+
   @CheckResult
   public PlayerInfo copyWithTrackSelectionParameters(TrackSelectionParameters parameters) {
     return new Builder(this).setTrackSelectionParameters(parameters).build();
@@ -612,6 +628,7 @@ import java.lang.annotation.Target;
       long seekBackIncrementMs,
       long seekForwardIncrementMs,
       long maxSeekToPreviousPositionMs,
+      Tracks currentTracks,
       TrackSelectionParameters parameters) {
     this.playerError = playerError;
     this.mediaItemTransitionReason = mediaItemTransitionReason;
@@ -641,6 +658,7 @@ import java.lang.annotation.Target;
     this.seekBackIncrementMs = seekBackIncrementMs;
     this.seekForwardIncrementMs = seekForwardIncrementMs;
     this.maxSeekToPreviousPositionMs = maxSeekToPreviousPositionMs;
+    this.currentTracks = currentTracks;
     this.trackSelectionParameters = parameters;
   }
 
@@ -696,6 +714,7 @@ import java.lang.annotation.Target;
     FIELD_SEEK_FORWARD_INCREMENT_MS,
     FIELD_MAX_SEEK_TO_PREVIOUS_POSITION_MS,
     FIELD_TRACK_SELECTION_PARAMETERS,
+    FIELD_CURRENT_TRACKS,
   })
   private @interface FieldNumber {}
 
@@ -728,7 +747,8 @@ import java.lang.annotation.Target;
   private static final int FIELD_SEEK_FORWARD_INCREMENT_MS = 27;
   private static final int FIELD_MAX_SEEK_TO_PREVIOUS_POSITION_MS = 28;
   private static final int FIELD_TRACK_SELECTION_PARAMETERS = 29;
-  // Next field key = 30
+  private static final int FIELD_CURRENT_TRACKS = 30;
+  // Next field key = 31
 
   public Bundle toBundle(
       boolean excludeMediaItems,
@@ -774,6 +794,7 @@ import java.lang.annotation.Target;
     bundle.putLong(keyForField(FIELD_SEEK_FORWARD_INCREMENT_MS), seekForwardIncrementMs);
     bundle.putLong(
         keyForField(FIELD_MAX_SEEK_TO_PREVIOUS_POSITION_MS), maxSeekToPreviousPositionMs);
+    bundle.putBundle(keyForField(FIELD_CURRENT_TRACKS), currentTracks.toBundle());
     bundle.putBundle(
         keyForField(FIELD_TRACK_SELECTION_PARAMETERS), trackSelectionParameters.toBundle());
 
@@ -886,6 +907,9 @@ import java.lang.annotation.Target;
         bundle.getLong(keyForField(FIELD_SEEK_FORWARD_INCREMENT_MS), /* defaultValue= */ 0);
     long maxSeekToPreviousPosition =
         bundle.getLong(keyForField(FIELD_MAX_SEEK_TO_PREVIOUS_POSITION_MS), /* defaultValue= */ 0);
+    Bundle currentTracksBundle = bundle.getBundle(keyForField(FIELD_CURRENT_TRACKS));
+    Tracks currentTracks =
+        currentTracksBundle == null ? Tracks.EMPTY : Tracks.CREATOR.fromBundle(currentTracksBundle);
     @Nullable
     Bundle trackSelectionParametersBundle =
         bundle.getBundle(keyForField(FIELD_TRACK_SELECTION_PARAMETERS));
@@ -922,6 +946,7 @@ import java.lang.annotation.Target;
         seekBackIncrementMs,
         seekForwardIncrementMs,
         maxSeekToPreviousPosition,
+        currentTracks,
         trackSelectionParameters);
   }
 

libraries/session/src/main/java/androidx/media3/session/PlayerWrapper.java

@@ -951,6 +951,7 @@ import java.util.List;
         getSeekBackIncrement(),
         getSeekForwardIncrement(),
         getMaxSeekToPreviousPosition(),
+        getCurrentTracks(),
         getTrackSelectionParameters());
   }
 

libraries/test_session_common/src/main/aidl/androidx/media3/test/session/common/IRemoteMediaSession.aidl

@@ -85,4 +85,5 @@ interface IRemoteMediaSession {
   void notifyRenderedFirstFrame(String sessionId);
   void notifyMaxSeekToPreviousPositionChanged(String sessionid, long maxSeekToPreviousPositionMs);
   void notifyTrackSelectionParametersChanged(String sessionId, in Bundle parameters);
+  void notifyTracksChanged(String sessionId, in Bundle tracks);
 }

libraries/test_session_common/src/main/java/androidx/media3/test/session/common/CommonConstants.java

@@ -103,6 +103,7 @@ public class CommonConstants {
   public static final String KEY_MEDIA_METADATA = "mediaMetadata";
   public static final String KEY_MAX_SEEK_TO_PREVIOUS_POSITION_MS = "maxSeekToPreviousPositionMs";
   public static final String KEY_TRACK_SELECTION_PARAMETERS = "trackSelectionParameters";
+  public static final String KEY_CURRENT_TRACKS = "currentTracks";
 
   // SessionCompat arguments
   public static final String KEY_SESSION_COMPAT_TOKEN = "sessionCompatToken";

libraries/test_session_current/src/androidTest/java/androidx/media3/session/MediaControllerListenerTest.java

@@ -50,6 +50,7 @@ import androidx.media3.common.AudioAttributes;
 import androidx.media3.common.C;
 import androidx.media3.common.DeviceInfo;
 import androidx.media3.common.FlagSet;
+import androidx.media3.common.Format;
 import androidx.media3.common.MediaItem;
 import androidx.media3.common.MediaMetadata;
 import androidx.media3.common.PlaybackException;
@@ -62,7 +63,9 @@ import androidx.media3.common.Player.PositionInfo;
 import androidx.media3.common.Player.RepeatMode;
 import androidx.media3.common.Player.State;
 import androidx.media3.common.Timeline;
+import androidx.media3.common.TrackGroup;
 import androidx.media3.common.TrackSelectionParameters;
+import androidx.media3.common.Tracks;
 import androidx.media3.common.VideoSize;
 import androidx.media3.common.text.Cue;
 import androidx.media3.common.text.CueGroup;
@@ -829,6 +832,52 @@ public class MediaControllerListenerTest {
     assertThat(parametersFromGetterRef.get()).isEqualTo(parameters);
   }
 
+  @Test
+  public void onTracksChanged() throws Exception {
+    RemoteMediaSession.RemoteMockPlayer player = remoteSession.getMockPlayer();
+    ImmutableList<Tracks.Group> trackGroups =
+        ImmutableList.of(
+            new Tracks.Group(
+                new TrackGroup(new Format.Builder().setChannelCount(2).build()),
+                /* adaptiveSupported= */ false,
+                /* trackSupport= */ new int[1],
+                /* trackSelected= */ new boolean[1]),
+            new Tracks.Group(
+                new TrackGroup(new Format.Builder().setHeight(1024).build()),
+                /* adaptiveSupported= */ false,
+                /* trackSupport= */ new int[1],
+                /* trackSelected= */ new boolean[1]));
+    Tracks currentTracks = new Tracks(trackGroups);
+    MediaController controller = controllerTestRule.createController(remoteSession.getToken());
+    AtomicReference<Tracks> changedCurrentTracksFromParamRef = new AtomicReference<>();
+    AtomicReference<Tracks> changedCurrentTracksFromGetterRef = new AtomicReference<>();
+    CountDownLatch latch = new CountDownLatch(1);
+    Player.Listener listener =
+        new Player.Listener() {
+          @Override
+          public void onTracksChanged(Tracks currentTracks) {
+            changedCurrentTracksFromParamRef.set(currentTracks);
+            changedCurrentTracksFromGetterRef.set(controller.getCurrentTracks());
+            latch.countDown();
+          }
+        };
+    AtomicReference<Tracks> initialCurrentTracksRef = new AtomicReference<>();
+    threadTestRule
+        .getHandler()
+        .postAndSync(
+            () -> {
+              initialCurrentTracksRef.set(controller.getCurrentTracks());
+              controller.addListener(listener);
+            });
+
+    player.notifyTracksChanged(currentTracks);
+
+    assertThat(latch.await(TIMEOUT_MS, MILLISECONDS)).isTrue();
+    assertThat(initialCurrentTracksRef.get()).isEqualTo(Tracks.EMPTY);
+    assertThat(changedCurrentTracksFromParamRef.get()).isEqualTo(currentTracks);
+    assertThat(changedCurrentTracksFromGetterRef.get()).isEqualTo(currentTracks);
+  }
+
   /** This also tests {@link MediaController#getShuffleModeEnabled()}. */
   @Test
   public void onShuffleModeEnabledChanged() throws Exception {

libraries/test_session_current/src/androidTest/java/androidx/media3/session/MediaControllerTest.java

@@ -35,6 +35,7 @@ import android.os.Bundle;
 import android.os.RemoteException;
 import androidx.media3.common.AudioAttributes;
 import androidx.media3.common.C;
+import androidx.media3.common.Format;
 import androidx.media3.common.HeartRating;
 import androidx.media3.common.IllegalSeekPositionException;
 import androidx.media3.common.MediaItem;
@@ -47,7 +48,9 @@ import androidx.media3.common.Player.RepeatMode;
 import androidx.media3.common.Rating;
 import androidx.media3.common.StarRating;
 import androidx.media3.common.Timeline;
+import androidx.media3.common.TrackGroup;
 import androidx.media3.common.TrackSelectionParameters;
+import androidx.media3.common.Tracks;
 import androidx.media3.common.VideoSize;
 import androidx.media3.common.util.Util;
 import androidx.media3.test.session.common.HandlerThreadTestRule;
@@ -283,6 +286,22 @@ public class MediaControllerTest {
     long seekBackIncrementMs = 1_000;
     long seekForwardIncrementMs = 2_000;
     long maxSeekToPreviousPositionMs = 300;
+    ImmutableList<Tracks.Group> trackGroups =
+        new ImmutableList.Builder<Tracks.Group>()
+            .add(
+                new Tracks.Group(
+                    new TrackGroup(new Format.Builder().setChannelCount(2).build()),
+                    /* adaptiveSupported= */ false,
+                    /* trackSupport= */ new int[1],
+                    /* trackSelected= */ new boolean[1]))
+            .add(
+                new Tracks.Group(
+                    new TrackGroup(new Format.Builder().setHeight(1024).build()),
+                    /* adaptiveSupported= */ false,
+                    /* trackSupport= */ new int[1],
+                    /* trackSelected= */ new boolean[1]))
+            .build();
+    Tracks currentTracks = new Tracks(trackGroups);
     TrackSelectionParameters trackSelectionParameters =
         TrackSelectionParameters.DEFAULT_WITHOUT_CONTEXT.buildUpon().setMaxVideoSizeSd().build();
     Timeline timeline = MediaTestUtils.createTimeline(5);
@@ -316,6 +335,7 @@ public class MediaControllerTest {
             .setSeekForwardIncrement(seekForwardIncrementMs)
             .setMaxSeekToPreviousPositionMs(maxSeekToPreviousPositionMs)
             .setTrackSelectionParameters(trackSelectionParameters)
+            .setCurrentTracks(currentTracks)
             .setTimeline(timeline)
             .setCurrentMediaItemIndex(currentMediaItemIndex)
             .build();
@@ -347,6 +367,7 @@ public class MediaControllerTest {
     AtomicLong seekBackIncrementRef = new AtomicLong();
     AtomicLong seekForwardIncrementRef = new AtomicLong();
     AtomicLong maxSeekToPreviousPositionMsRef = new AtomicLong();
+    AtomicReference<Tracks> currentTracksRef = new AtomicReference<>();
     AtomicReference<TrackSelectionParameters> trackSelectionParametersRef = new AtomicReference<>();
     AtomicReference<Timeline> timelineRef = new AtomicReference<>();
     AtomicInteger currentMediaItemIndexRef = new AtomicInteger();
@@ -379,6 +400,7 @@ public class MediaControllerTest {
               seekBackIncrementRef.set(controller.getSeekBackIncrement());
               seekForwardIncrementRef.set(controller.getSeekForwardIncrement());
               maxSeekToPreviousPositionMsRef.set(controller.getMaxSeekToPreviousPosition());
+              currentTracksRef.set(controller.getCurrentTracks());
               trackSelectionParametersRef.set(controller.getTrackSelectionParameters());
               timelineRef.set(controller.getCurrentTimeline());
               currentMediaItemIndexRef.set(controller.getCurrentMediaItemIndex());
@@ -409,6 +431,7 @@ public class MediaControllerTest {
     assertThat(seekForwardIncrementRef.get()).isEqualTo(seekForwardIncrementMs);
     assertThat(maxSeekToPreviousPositionMsRef.get()).isEqualTo(maxSeekToPreviousPositionMs);
     assertThat(trackSelectionParametersRef.get()).isEqualTo(trackSelectionParameters);
+    assertThat(currentTracksRef.get()).isEqualTo(currentTracks);
     assertTimelineMediaItemsEquals(timelineRef.get(), timeline);
     assertThat(currentMediaItemIndexRef.get()).isEqualTo(currentMediaItemIndex);
     assertThat(currentMediaItemRef.get()).isEqualTo(currentMediaItem);

libraries/test_session_current/src/main/java/androidx/media3/session/MediaSessionProviderService.java

@@ -29,6 +29,7 @@ import static androidx.media3.test.session.common.CommonConstants.KEY_CURRENT_LI
 import static androidx.media3.test.session.common.CommonConstants.KEY_CURRENT_MEDIA_ITEM_INDEX;
 import static androidx.media3.test.session.common.CommonConstants.KEY_CURRENT_PERIOD_INDEX;
 import static androidx.media3.test.session.common.CommonConstants.KEY_CURRENT_POSITION;
+import static androidx.media3.test.session.common.CommonConstants.KEY_CURRENT_TRACKS;
 import static androidx.media3.test.session.common.CommonConstants.KEY_DEVICE_INFO;
 import static androidx.media3.test.session.common.CommonConstants.KEY_DEVICE_MUTED;
 import static androidx.media3.test.session.common.CommonConstants.KEY_DEVICE_VOLUME;
@@ -79,6 +80,7 @@ import androidx.media3.common.Player.DiscontinuityReason;
 import androidx.media3.common.Player.PositionInfo;
 import androidx.media3.common.Timeline;
 import androidx.media3.common.TrackSelectionParameters;
+import androidx.media3.common.Tracks;
 import androidx.media3.common.VideoSize;
 import androidx.media3.common.text.CueGroup;
 import androidx.media3.common.util.Log;
@@ -355,6 +357,10 @@ public class MediaSessionProviderService extends Service {
       }
       player.maxSeekToPreviousPositionMs =
           config.getLong(KEY_MAX_SEEK_TO_PREVIOUS_POSITION_MS, player.maxSeekToPreviousPositionMs);
+      @Nullable Bundle currentTracksBundle = config.getBundle(KEY_CURRENT_TRACKS);
+      if (currentTracksBundle != null) {
+        player.currentTracks = Tracks.CREATOR.fromBundle(currentTracksBundle);
+      }
       @Nullable
       Bundle trackSelectionParametersBundle = config.getBundle(KEY_TRACK_SELECTION_PARAMETERS);
       if (trackSelectionParametersBundle != null) {
@@ -1004,5 +1010,17 @@ public class MediaSessionProviderService extends Service {
             player.notifyTrackSelectionParametersChanged();
           });
     }
+
+    @Override
+    public void notifyTracksChanged(String sessionId, Bundle tracksBundle) throws RemoteException {
+      Tracks tracks = Tracks.CREATOR.fromBundle(tracksBundle);
+      runOnHandler(
+          () -> {
+            MediaSession session = sessionMap.get(sessionId);
+            MockPlayer player = (MockPlayer) session.getPlayer();
+            player.currentTracks = tracks;
+            player.notifyTracksChanged();
+          });
+    }
   }
 }

libraries/test_session_current/src/main/java/androidx/media3/session/MockPlayer.java

@@ -251,6 +251,7 @@ public class MockPlayer implements Player {
   public long seekForwardIncrementMs;
   public long maxSeekToPreviousPositionMs;
   public TrackSelectionParameters trackSelectionParameters;
+  public Tracks currentTracks;
 
   private MockPlayer(Builder builder) {
     changePlayerStateWithTransportControl = builder.changePlayerStateWithTransportControl;
@@ -299,6 +300,7 @@ public class MockPlayer implements Player {
 
     commands = new Player.Commands.Builder().addAllCommands().build();
 
+    currentTracks = Tracks.EMPTY;
     trackSelectionParameters = TrackSelectionParameters.DEFAULT_WITHOUT_CONTEXT;
   }
 
@@ -1177,6 +1179,22 @@ public class MockPlayer implements Player {
     }
   }
 
+  @Override
+  public Tracks getCurrentTracks() {
+    return currentTracks;
+  }
+
+  @Override
+  public TrackSelectionParameters getTrackSelectionParameters() {
+    return trackSelectionParameters;
+  }
+
+  @Override
+  public void setTrackSelectionParameters(TrackSelectionParameters parameters) {
+    trackSelectionParameters = parameters;
+    checkNotNull(conditionVariables.get(METHOD_SET_TRACK_SELECTION_PARAMETERS)).open();
+  }
+
   public boolean surfaceExists() {
     return surface != null;
   }
@@ -1225,20 +1243,10 @@ public class MockPlayer implements Player {
     }
   }
 
-  @Override
+  public void notifyTracksChanged() {
-  public Tracks getCurrentTracks() {
+    for (Listener listener : listeners) {
-    throw new UnsupportedOperationException();
+      listener.onTracksChanged(currentTracks);
-  }
+    }
-
-  @Override
-  public TrackSelectionParameters getTrackSelectionParameters() {
-    return trackSelectionParameters;
-  }
-
-  @Override
-  public void setTrackSelectionParameters(TrackSelectionParameters parameters) {
-    trackSelectionParameters = parameters;
-    checkNotNull(conditionVariables.get(METHOD_SET_TRACK_SELECTION_PARAMETERS)).open();
   }
 
   @Override

libraries/test_session_current/src/main/java/androidx/media3/session/RemoteMediaSession.java

@@ -29,6 +29,7 @@ import static androidx.media3.test.session.common.CommonConstants.KEY_CURRENT_LI
 import static androidx.media3.test.session.common.CommonConstants.KEY_CURRENT_MEDIA_ITEM_INDEX;
 import static androidx.media3.test.session.common.CommonConstants.KEY_CURRENT_PERIOD_INDEX;
 import static androidx.media3.test.session.common.CommonConstants.KEY_CURRENT_POSITION;
+import static androidx.media3.test.session.common.CommonConstants.KEY_CURRENT_TRACKS;
 import static androidx.media3.test.session.common.CommonConstants.KEY_DEVICE_INFO;
 import static androidx.media3.test.session.common.CommonConstants.KEY_DEVICE_MUTED;
 import static androidx.media3.test.session.common.CommonConstants.KEY_DEVICE_VOLUME;
@@ -77,6 +78,7 @@ import androidx.media3.common.Player.DiscontinuityReason;
 import androidx.media3.common.Player.PositionInfo;
 import androidx.media3.common.Timeline;
 import androidx.media3.common.TrackSelectionParameters;
+import androidx.media3.common.Tracks;
 import androidx.media3.common.VideoSize;
 import androidx.media3.common.text.CueGroup;
 import androidx.media3.common.util.Log;
@@ -421,6 +423,10 @@ public class RemoteMediaSession {
         throws RemoteException {
       binder.notifyTrackSelectionParametersChanged(sessionId, parameters.toBundle());
     }
+
+    public void notifyTracksChanged(Tracks tracks) throws RemoteException {
+      binder.notifyTracksChanged(sessionId, tracks.toBundle());
+    }
   }
 
   ////////////////////////////////////////////////////////////////////////////////
@@ -687,6 +693,11 @@ public class RemoteMediaSession {
       return this;
     }
 
+    public MockPlayerConfigBuilder setCurrentTracks(Tracks tracks) {
+      bundle.putBundle(KEY_CURRENT_TRACKS, tracks.toBundle());
+      return this;
+    }
+
     public Bundle build() {
       return bundle;
     }