Show notification even in STATE_IDLE

Currently the notification disappears immediately when the player
enters an error or stopped state, but still has its media and
could resume on user request.

This can be fixed by only checking the existence of media and not
the state when deciding to show a notification.

PiperOrigin-RevId: 726901050

RELEASENOTES.md

@@ -35,6 +35,9 @@
 *   Muxers:
 *   IMA extension:
 *   Session:
+    *   Keep notification visible when playback enters an error or stopped
+        state. The notification is only removed if the playlist is cleared or
+        the player is released.
 *   UI:
 *   Downloads:
 *   OkHttp Extension:

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

@@ -251,9 +251,7 @@ import java.util.concurrent.TimeoutException;
 
   private boolean shouldShowNotification(MediaSession session) {
     MediaController controller = getConnectedControllerForSession(session);
-    return controller != null
+    return controller != null && !controller.getCurrentTimeline().isEmpty();
-        && !controller.getCurrentTimeline().isEmpty()
-        && controller.getPlaybackState() != Player.STATE_IDLE;
   }
 
   @Nullable

libraries/session/src/test/java/androidx/media3/session/MediaSessionServiceTest.java

@@ -67,6 +67,55 @@ public class MediaSessionServiceTest {
         (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
   }
 
+  @Test
+  public void service_sessionIdleNoMedia_createsNoNotification() {
+    ExoPlayer player = new TestExoPlayerBuilder(context).build();
+    MediaSession session = new MediaSession.Builder(context, player).build();
+    ServiceController<TestService> serviceController = Robolectric.buildService(TestService.class);
+    TestService service = serviceController.create().get();
+    service.setMediaNotificationProvider(
+        new DefaultMediaNotificationProvider(
+            service,
+            /* notificationIdProvider= */ unused -> 2000,
+            DefaultMediaNotificationProvider.DEFAULT_CHANNEL_ID,
+            DefaultMediaNotificationProvider.DEFAULT_CHANNEL_NAME_RESOURCE_ID));
+    service.addSession(session);
+
+    // Give the service a chance to create a notification.
+    ShadowLooper.idleMainLooper();
+
+    assertThat(getStatusBarNotification(2000)).isNull();
+
+    session.release();
+    player.release();
+    serviceController.destroy();
+  }
+
+  @Test
+  public void service_sessionIdleWithMedia_createsNotification() {
+    ExoPlayer player = new TestExoPlayerBuilder(context).build();
+    MediaSession session = new MediaSession.Builder(context, player).build();
+    ServiceController<TestService> serviceController = Robolectric.buildService(TestService.class);
+    TestService service = serviceController.create().get();
+    service.setMediaNotificationProvider(
+        new DefaultMediaNotificationProvider(
+            service,
+            /* notificationIdProvider= */ unused -> 2000,
+            DefaultMediaNotificationProvider.DEFAULT_CHANNEL_ID,
+            DefaultMediaNotificationProvider.DEFAULT_CHANNEL_NAME_RESOURCE_ID));
+    service.addSession(session);
+
+    // Add media and give the service a chance to create a notification.
+    player.setMediaItem(MediaItem.fromUri("asset:///media/mp4/sample.mp4"));
+    ShadowLooper.idleMainLooper();
+
+    assertThat(getStatusBarNotification(2000)).isNotNull();
+
+    session.release();
+    player.release();
+    serviceController.destroy();
+  }
+
   @Test
   public void service_multipleSessionsOnMainThread_createsNotificationForEachSession() {
     ExoPlayer player1 = new TestExoPlayerBuilder(context).build();