iOS：如何防止视频播放器在去往后台时消失？

Question

我有一个mpMoviePlayerViewController，可以从远程服务器流式传输视频。这一切都运行良好，但我注意到，如果我将应用程序发送到后台（通过按主页按钮），当我重新打开它时，mpMoviePlayerViewController停止播放并消失。

这是我的代码：

-(void)playVideo:(NSURL *)url{
    mpViewController = [[MPMoviePlayerViewController alloc] initWithContentURL:url];

    if (mpViewController){
        [[NSNotificationCenter defaultCenter]
         addObserver: self
         selector: @selector(myMovieFinishedCallback:)
         name: MPMoviePlayerPlaybackDidFinishNotification
         object: mpViewController.moviePlayer];


        [[NSNotificationCenter defaultCenter]
         addObserver: self
         selector: @selector(myMoviePreloadCallback:)
         name: MPMoviePlayerLoadStateDidChangeNotification
         object: mpViewController.moviePlayer];
    }
}

-(void) myMoviePreloadCallback: (NSNotification*) aNotification{

    [self performSelectorOnMainThread:@selector(myMoviePreloadCallbackMainThread) withObject:nil waitUntilDone:NO];
}

-(void)myMoviePreloadCallbackMainThread{

    [[NSNotificationCenter defaultCenter]
     removeObserver: self
     name: MPMoviePlayerLoadStateDidChangeNotification
     object: mpViewController.moviePlayer];

    [self presentMoviePlayerViewControllerAnimated:mpViewController];

    [mpViewController.moviePlayer play];
}

-(void) myMovieFinishedCallback: (NSNotification*) aNotification
{

    [[NSNotificationCenter defaultCenter]
     removeObserver: self
     name: MPMoviePlayerPlaybackDidFinishNotification
     object: mpViewController.moviePlayer];

    [mpViewController.moviePlayer stop];
    [self dismissMoviePlayerViewControllerAnimated];
    [mpViewController release];
}

有没有办法让玩家从停止的地方继续玩？