Add isReleased() to the Exoplayer

This avoids having to add AnalyticsListener and catching the `onPlayerReleased` callback.

The `Exoplayer.release()` method is blocking and one can be sure that the player is released if the call returned. However, the method is useful for UI testing and asserting that the player is released after a certain UI action, e.g. closing the activity or detaching a window.

PiperOrigin-RevId: 640114416

RELEASENOTES.md

@@ -60,6 +60,8 @@
         resulted in `Source Error` and `IllegalArgumentException`.
     *   Use data class for `LoadControl` methods instead of individual
         parameters.
+    *   Add `ExoPlayer.isReleased()` to check whether `Exoplayer.release()` has
+        been called.
 *   Transformer:
     *   Work around a decoder bug where the number of audio channels was capped
         at stereo when handling PCM input.

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/ExoPlayer.java

@@ -1956,6 +1956,23 @@ public interface ExoPlayer extends Player {
   @UnstableApi
   boolean isTunnelingEnabled();
 
+  /**
+   * {@inheritDoc}
+   *
+   * <p>The exception to the above rule is {@link #isReleased()} which can be called on a released
+   * player.
+   */
+  @Override
+  void release();
+
+  /**
+   * Returns whether {@link #release()} has been called on the player.
+   *
+   * <p>This method is allowed to be called after {@link #release()}.
+   */
+  @UnstableApi
+  boolean isReleased();
+
   /**
    * Sets the {@link ImageOutput} where rendered images will be forwarded.
    *

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/ExoPlayerImpl.java

@@ -1105,6 +1105,12 @@ import java.util.concurrent.TimeoutException;
     playerReleased = true;
   }
 
+  @Override
+  public boolean isReleased() {
+    verifyApplicationThread();
+    return playerReleased;
+  }
+
   @Override
   public PlayerMessage createMessage(Target target) {
     verifyApplicationThread();

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/SimpleExoPlayer.java

@@ -1346,6 +1346,11 @@ public class SimpleExoPlayer extends BasePlayer
     return player.isTunnelingEnabled();
   }
 
+  @Override
+  public boolean isReleased() {
+    return player.isReleased();
+  }
+
   @Override
   public void setImageOutput(ImageOutput imageOutput) {
     blockUntilConstructorFinished();

libraries/test_utils/src/main/java/androidx/media3/test/utils/StubExoPlayer.java

@@ -428,6 +428,11 @@ public class StubExoPlayer extends StubPlayer implements ExoPlayer {
     throw new UnsupportedOperationException();
   }
 
+  @Override
+  public boolean isReleased() {
+    throw new UnsupportedOperationException();
+  }
+
   @Override
   public void setImageOutput(ImageOutput imageOutput) {
     throw new UnsupportedOperationException();