Iphone 如何从图书馆获取音乐文件

我正在开发一个应用程序。我需要从电话库中获取音乐文件。为此，我使用MPMediaPickerCOntroller。但它不会触发didpickingitem委托方法。我的代码如下所示

- (void)viewDidLoad
 {
[super viewDidLoad];
MPMediaPickerController *picker =[[MPMediaPickerController alloc] initWithMediaTypes: MPMediaTypeMusic];
picker.delegate                     = self;
picker.allowsPickingMultipleItems   = YES;
picker.prompt                       =@"Add songs to play";
[self presentModalViewController:picker animated: YES];
}

 - (void) mediaPicker: (MPMediaPickerController *) mediaPicker didPickMediaItems: (MPMediaItemCollection *) mediaItemCollection 
   {
        NSLog(@"sdfadsf");
        NSLog(@"%@",mediaItemCollection);
        NSArray *slist=[mediaItemCollection copy];
         NSLog(@"%@",slist);

  }

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从这里阅读

您是否在.h中声明了MPMediaPickerController远程网关

例：

@界面FirstViewController:UIViewController

如果您不这样做，这将解释为什么该方法不触发。此外，我不相信它会在模拟器上工作；仅在设备上

编辑：

---

您确定要在

viewDidUnload

中执行此操作吗？它不适用于iPod Touch、iPhone和iPad。它叫做iPod库。我声明了它。我在模拟器上测试过。@user1400581是的，模拟器没有音乐，所以你不能在上面测试。我还编辑了我的帖子，向大家展示了我是如何展示媒体采集器的。注意：只有当媒体选择器启动且用户选择歌曲时，才会调用didPick方法。

-(IBAction)presentLibrary:(id)sender
{
    //this is called from a button press, but you could do it in viewDidLoad
    MPMediaPickerController *picker = [[MPMediaPickerController alloc] initWithMediaTypes: MPMediaTypeMusic];
    picker.delegate = self;
    picker.allowsPickingMultipleItems = NO;
    picker.prompt  = NSLocalizedString (@"Select any song from the list", @"Prompt to user to choose some songs to play");
    [self presentModalViewController: picker animated: YES];    
}

- (void)mediaPicker:(MPMediaPickerController *)mediaPicker didPickMediaItems:(MPMediaItemCollection *)mediaItemCollection
{
     NSLog(@"didpick");
    if (mediaItemCollection) {
        [_mediaPlayer setQueueWithItemCollection: mediaItemCollection];
        _mediaCollection = mediaItemCollection;
    }

    [mediaPicker dismissModalViewControllerAnimated:YES];
}