MPMoviePlayer 播放视频后出现错误访问错误

Question

我创建了一个新的 ViewController（仅包含 .h 和 .m 文件）并添加了该代码来播放视频。视频播放完毕后，我收到“Exe_bad_access”错误。

将“NSZombieEnabled=true”添加到可执行文件作为参数时出现错误消息：

---

“测试播放视频[654:207] -[MPMoviePlayerController stop]：消息发送到已释放的实例 0x63042d0"

---

这是什么问题？播放视频时如何进行正确的内存管理？

#import "TestPlayingVideoViewController.h"
#import <MediaPlayer/MediaPlayer.h>

@implementation TestPlayingVideoViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    [self.view setBackgroundColor:[UIColor darkGrayColor]];


    UIButton* btn = [[UIButton alloc] initWithFrame:CGRectMake(50 , 50, 200, 25)];
    [btn setTitle:@"press me" forState:UIControlStateNormal];
    [btn addTarget:self action:@selector(action:)    forControlEvents:UIControlEventTouchUpInside];

    [self.view addSubview:btn];
    [btn release];
}

- (void)action:(id)sender
{
    NSLog(@"UIButton was clicked");

     NSString *url   =   [[NSBundle mainBundle] pathForResource:@"mymovie" ofType:@"m4v"];
     MPMoviePlayerViewController* moviePlayerController = [[MPMoviePlayerViewController alloc] initWithContentURL:[NSURL fileURLWithPath:url] ];

     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(moviePlayBackComplete:) name:MPMoviePlayerPlaybackDidFinishNotification object:moviePlayerController.moviePlayer];
     [moviePlayerController.moviePlayer play];

     //[self.view addSubview:moviePlayerController.view];
    [self presentMoviePlayerViewControllerAnimated:moviePlayerController];
}


- (void) moviePlayBackComplete:(NSNotification*) notification {

    MPMoviePlayerController* player = [notification object];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:MPMoviePlayerPlaybackDidFinishNotification object:player]; 
    [self dismissMoviePlayerViewControllerAnimated];

    [player stop];
    //[self.view removeFromSuperView];
    [player release];
}


- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    return YES;
}

- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.
}

- (void)viewDidUnload {
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}


- (void)dealloc {
    [super dealloc];
}

@end

Answer 1

对于您要发布的内容，这里存在很多混乱：例如，这是您的电影播放器​​的主要分配：

 MPMoviePlayerViewController* moviePlayerController = [[MPMoviePlayerViewController alloc] initWithContentURL:[NSURL fileURLWithPath:url] ];

但是您要发布的不是这个 moviePlayerController - 您只是发布了 . MPMoviePlayerController 的 moviePlayer 属性。请注意，当您创建 NSNotification 时，您将传递 moviePlayerController.movi​​ePlayer，而不是简单地传递 moviePlayerController。

因此，您没有释放 moviePlayerController，实际上是在尝试释放该对象的属性。你不应该这样做 - 你应该释放该对象，并让它担心释放其属性。