I am developing a radio app using media3. The app has a MediaLibraryService for playback and a Fragment that controls the UI. The Fragment listens to playback changes using a Player.Listener that has been added to a MediaController. That all works great so far.

I recently began integrating Google Cast into the app. Playback through a CastPlayer in the MediaLibraryService works fine. But now I am stuck: How do I receive information about CastPlayer playback state changes in my Fragment? The existing Player.Listener (basically created in the way recommended here) does not get called at the moment.