I cant Stop my video which is playing in YTPlayerView ios

In my ios app I am using Googles YTPlayerView to load You tube videos, I can able to Play videos , But i cant able to stop The videos which is playing, on tap of Done button of the webviews Player It is exiting from full screen and automatically opening fullscreen, How do i stop the Videos ? i tried the following code to get notification on tap on Done but its not getting called

[[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(playbackDidEnd:)
                                                 name:@"MPAVControllerItemPlaybackDidEndNotification"
                                               object:nil];

Is there any way to stop the videos or is there any way to get notification for Done Button Tap?

I also tried YTPlayerView's delegate method but it is not called on tap of done -(void)playerView:(YTPlayerView *)playerView didChangeToState:(YTPlayerState)state