Add notification for empty player setting

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

@@ -37,6 +37,7 @@
 import androidx.media3.common.Player;
 import androidx.media3.common.util.Log;
 import androidx.media3.common.util.Util;
+import androidx.media3.session.MediaSessionService.ShowNotificationForEmptyPlayerMode;
 import androidx.media3.session.MediaSessionService.ShowNotificationForIdlePlayerMode;
 import com.google.common.collect.ImmutableList;
 import com.google.common.util.concurrent.FutureCallback;
@@ -79,6 +80,7 @@
   private boolean isUserEngagedTimeoutEnabled;
   private long userEngagedTimeoutMs;
   @ShowNotificationForIdlePlayerMode int showNotificationForIdlePlayerMode;
+  @ShowNotificationForEmptyPlayerMode int showNotificationForEmptyPlayerMode;
 
   public MediaNotificationManager(
       MediaSessionService mediaSessionService,
@@ -97,6 +99,8 @@ public MediaNotificationManager(
     userEngagedTimeoutMs = MediaSessionService.DEFAULT_FOREGROUND_SERVICE_TIMEOUT_MS;
     showNotificationForIdlePlayerMode =
         MediaSessionService.SHOW_NOTIFICATION_FOR_IDLE_PLAYER_AFTER_STOP_OR_ERROR;
+    showNotificationForEmptyPlayerMode =
+        MediaSessionService.SHOW_NOTIFICATION_FOR_EMPTY_PLAYER_NEVER;
   }
 
   public void addSession(MediaSession session) {
@@ -212,6 +216,16 @@ public void setShowNotificationForIdlePlayer(
     }
   }
 
+  public void setShowNotificationForEmptyPlayer(
+      @ShowNotificationForEmptyPlayerMode int showNotificationForEmptyPlayerMode) {
+    this.showNotificationForEmptyPlayerMode = showNotificationForEmptyPlayerMode;
+    List<MediaSession> sessions = mediaSessionService.getSessions();
+    for (int i = 0; i < sessions.size(); i++) {
+      mediaSessionService.onUpdateNotificationInternal(
+          sessions.get(i), /* startInForegroundWhenPaused= */ false);
+    }
+  }
+
   @Override
   public boolean handleMessage(Message msg) {
     if (msg.what == MSG_USER_ENGAGED_TIMEOUT) {
@@ -322,10 +336,25 @@ private void removeNotification() {
 
   private boolean shouldShowNotification(MediaSession session) {
     MediaController controller = getConnectedControllerForSession(session);
-    if (controller == null || controller.getCurrentTimeline().isEmpty()) {
+    if (controller == null) {
       return false;
     }
     ControllerInfo controllerInfo = checkNotNull(controllerMap.get(session));
+    if (controller.getCurrentTimeline().isEmpty()) {
+      switch (showNotificationForEmptyPlayerMode) {
+        case MediaSessionService.SHOW_NOTIFICATION_FOR_EMPTY_PLAYER_ALWAYS:
+          break;
+        case MediaSessionService.SHOW_NOTIFICATION_FOR_EMPTY_PLAYER_NEVER:
+          return false;
+        case MediaSessionService.SHOW_NOTIFICATION_FOR_EMPTY_PLAYER_AFTER_STOP_OR_ERROR:
+          if (!controllerInfo.hasBeenPrepared) {
+            return false;
+          }
+          break;
+        default:
+          throw new IllegalStateException();
+      }
+    }
     if (controller.getPlaybackState() != Player.STATE_IDLE) {
       // Playback first prepared or restarted, reset previous notification dismissed flag.
       controllerInfo.wasNotificationDismissed = false;

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

@@ -194,8 +194,8 @@ default void onForegroundServiceStartNotAllowedException() {}
   public @interface ShowNotificationForIdlePlayerMode {}
 
   /**
-   * Always show a notification when the {@link Player} is in {@link Player#STATE_IDLE}, has media,
-   * and the notification wasn't explicitly dismissed.
+   * Always show a notification when the {@link Player} is in {@link Player#STATE_IDLE} and the
+   * notification wasn't explicitly dismissed.
    */
   @UnstableApi public static final int SHOW_NOTIFICATION_FOR_IDLE_PLAYER_ALWAYS = 1;
 
@@ -204,10 +204,45 @@ default void onForegroundServiceStartNotAllowedException() {}
 
   /**
    * Shows a notification when the {@link Player} is in {@link Player#STATE_IDLE} due to {@link
-   * Player#stop} or an error, has media, and the notification wasn't explicitly dismissed.
+   * Player#stop} or an error, and the notification wasn't explicitly dismissed.
    */
   @UnstableApi public static final int SHOW_NOTIFICATION_FOR_IDLE_PLAYER_AFTER_STOP_OR_ERROR = 3;
 
+  /**
+   * The behavior for showing notifications when the {@link Player} has no media.
+   *
+   * <p>One of {@link #SHOW_NOTIFICATION_FOR_EMPTY_PLAYER_ALWAYS}, {@link
+   * #SHOW_NOTIFICATION_FOR_EMPTY_PLAYER_NEVER}, {@link
+   * #SHOW_NOTIFICATION_FOR_EMPTY_PLAYER_AFTER_STOP_OR_ERROR}.
+   *
+   * <p>The default value is {@link #SHOW_NOTIFICATION_FOR_EMPTY_PLAYER_NEVER}.
+   */
+  @UnstableApi
+  @Documented
+  @Retention(RetentionPolicy.SOURCE)
+  @Target(TYPE_USE)
+  @IntDef({
+    SHOW_NOTIFICATION_FOR_EMPTY_PLAYER_ALWAYS,
+    SHOW_NOTIFICATION_FOR_EMPTY_PLAYER_NEVER,
+    SHOW_NOTIFICATION_FOR_EMPTY_PLAYER_AFTER_STOP_OR_ERROR
+  })
+  public @interface ShowNotificationForEmptyPlayerMode {}
+
+  /**
+   * Always show a notification when the {@link Player} is empty and the notification wasn't
+   * explicitly dismissed.
+   */
+  @UnstableApi public static final int SHOW_NOTIFICATION_FOR_EMPTY_PLAYER_ALWAYS = 1;
+
+  /** Never show a notification when the {@link Player} is empty. */
+  @UnstableApi public static final int SHOW_NOTIFICATION_FOR_EMPTY_PLAYER_NEVER = 2;
+
+  /**
+   * Shows a notification when the {@link Player} is empty, in {@link Player#STATE_IDLE} due to
+   * {@link Player#stop} or an error, and the notification wasn't explicitly dismissed.
+   */
+  @UnstableApi public static final int SHOW_NOTIFICATION_FOR_EMPTY_PLAYER_AFTER_STOP_OR_ERROR = 3;
+
   private static final String TAG = "MSessionService";
 
   private final Object lock;
@@ -547,6 +582,18 @@ public final void setShowNotificationForIdlePlayer(
         .setShowNotificationForIdlePlayer(showNotificationForIdlePlayerMode);
   }
 
+  /**
+   * Sets whether and when a notification for a {@link Player} that has no media should be shown.
+   *
+   * @param showNotificationForEmptyPlayerMode The {@link ShowNotificationForEmptyPlayerMode}.
+   */
+  @UnstableApi
+  public final void setShowNotificationForEmptyPlayer(
+      @ShowNotificationForEmptyPlayerMode int showNotificationForEmptyPlayerMode) {
+    getMediaNotificationManager()
+        .setShowNotificationForEmptyPlayer(showNotificationForEmptyPlayerMode);
+  }
+
   /**
    * Returns whether there is a session with ongoing user-engaged playback that is run in a
    * foreground service.