MPMoviePlayerController 存在黑色背景

我制作 iOS 应用程序。

我使用 MPMoviePlayerController，但这显示黑色背景。

我认为这个问题可以通过这个URL解决，但我不明白使用方式。
MPMoviePlayerController 背景颜色不会粘住 https://stackoverflow.com/questions/7974349/mpmovieplayercontroller-background-color-wont-stick

我的代码是这样的。

NSString *path = [[NSBundle mainBundle] pathForResource:@"movie_files" ofType:@"m4v"];
NSURL *videoURL = [NSURL fileURLWithPath:path];

moviePlayer =  [[MPMoviePlayerController alloc]
                initWithContentURL:videoURL];

//setting
moviePlayer.scalingMode =MPMovieScalingModeAspectFit;
moviePlayer.controlStyle=MPMovieControlStyleDefault;
moviePlayer.shouldAutoplay=NO;
[moviePlayer.view setFrame:CGRectMake(20, 20, 280, 200)];    

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

//clearColor
UIView *subV =[[UIView alloc]init];
for(subV in moviePlayer.backgroundView.subviews) {
    subV.backgroundColor = [UIColor clearColor];
}
[moviePlayer.view addSubview:subV];    
[self.view addSubview:moviePlayer.view];
//show white screen

请告知清楚的背景方式。

您需要将其更改为：

moviePlayer.backgroundView.backgroundColor = [UIColor clearColor];
for(UIView *aSubView in moviePlayer.view.subviews) {
    aSubView.backgroundColor = [UIColor clearColor];
}