怎么自定义 视频播放的声音 和 进度条

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//注册一个通知来观察状态
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(playbackStateDidChange:)
name:MPMoviePlayerPlaybackStateDidChangeNotification
object:[playerViewController moviePlayer]];


- (void)playbackStateDidChange:(NSNotification *)aNote
{
MPMoviePlayerController *moviePlayer = [aNote object];


switch (moviePlayer.playbackState) {
case MPMoviePlaybackStateStopped:
break;
case MPMoviePlaybackStatePlaying:

break;
case MPMoviePlaybackStatePaused:

break;
case MPMoviePlaybackStateInterrupted:

break;
case MPMoviePlaybackStateSeekingForward:

break;
case MPMoviePlaybackStateSeekingBackward:

break;
default:
break;
}



CGFloat playtime = [moviePlayer currentPlaybackTime];//当前时间

}