Question

In MonoTouch, we ran into this problem with the Movie Player sample in that it would only play the video once, but would not play it a second time.

I am asking this question to post an answer, since it has been hitting various folks.

Answer 1

MPMoviePlayerController is a singleton underneath the hood. If you have not properly release’d (ObjC) or Dispose()’d (MonoTouch) and you create a second instance, it will either not play, or play audio only.

Additionally if you subscribe to MPMoviePlayerScalingModeDidChangeNotification or MPMoviePlayerPlaybackDidFinishNotification or MPMoviePlayerContentPreloadDidFinishNotification, be warned that the posted NSNotification takes a reference to the MPMoviePlayerController as well, so if you keep it around, you will have a reference the player.

Although Mono’s Garbage Collector will eventually kick-in, this is a case where deterministic termination is wanted (you want the reference gone now, not gone when the GC decides to perform a collection).

This is why you want to call the Dispose () method on the controller, and the Dispose() method on the notification.

For example:

// Deterministic termination, do not wait for the GC
if (moviePlayer != null){
    moviePlayer.Dispose ()
    moviePlayer = null;
}

If you were listening to notifications, call Dispose in your notification handler at the end, to release the reference that it keeps to your MPMoviePlayerController for example:

var center = NSNotificationCenter.DefaultCenter;
center.AddObserver (
    "MPMoviePlayerPlaybackDidFinishNotification"),
    (notify) => { Console.WriteLine ("Done!"); notify.Dispose (); });