Question

I am first doing add observer call

followed by remove observer in the notification function.

I am certain that removerObserver is called as I see it on the stack
However, the app crashes as if a bad memory reference is left over in the notification center.

I think there are 2 possiblities

1. I am hitting an apple bug

2. My sequence of invocation is wrong

Here is my code from playvideo function

 //Initialize a MPMoviePlayerController object with the movie.
 moviePlayer = [[MPMoviePlayerController alloc] initWithContentURL:url];

[[NSNotificationCenter defaultCenter] addObserver:self 
                                     selector: @selector(movieReadyPlayMovieNow:) 
               name:MPMoviePlayerContentPreloadDidFinishNotification object:nil];  


 [[NSNotificationCenter defaultCenter] addObserver:self 
                                      selector: @selector(moviePlayBackFinished:) 
              name:MPMoviePlayerPlaybackDidFinishNotification object:moviePlayer];  

Here is Notification called when the movie is done preloading

- (void) movieReadyPlayMovieNow:(NSNotification*)notification {
    @try {
        if(moviePlayer != nil){   
             [[NSNotificationCenter defaultCenter] removeObserver:self 
                 name:MPMoviePlayerContentPreloadDidFinishNotification  
                 object:moviePlayer];    
             [moviePlayer play];  

        } 
   }
   catch(id exception) {
       NSLog(@"Error playing.");
   } 
} 

Answer 1

You’re registering from name:MPMoviePlayerContentPreloadDidFinishNotification notifications from any (nil) object:

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(movieReadyPlayMovieNow:) name:MPMoviePlayerContentPreloadDidFinishNotification object:nil];

But you’re de-registering specifically from the moviePlayer object.

[[NSNotificationCenter defaultCenter] removeObserver:self name:MPMoviePlayerContentPreloadDidFinishNotification object:moviePlayer];

Try either registering for the object nil on both, or moviePlayer on both and see if that solves the problem.