iOS 13：MPMediaPickerController-内部错误/找不到请求的应用程序扩展名

Question

似乎一般MPMediaPicker在ios13（ipad air 2，iphone SE）上不再起作用了

从那里复制的示例1：1未显示媒体选择器https://developer.apple.com/documentation/mediaplayer/displaying_a_media_picker_from_your_app

有关如何恢复功能的任何提示？

注1

[像这样使用MPMediaPickerController使用时

    musicPickerView = [[UIView alloc] initWithFrame:fullScreenRect];
    musicPickerView.alpha = 0.0f;
    musicPicker = [[MPMediaPickerController alloc] initWithMediaTypes:MPMediaTypeMusic];
    musicPicker.showsCloudItems               = false;
    musicPicker.showsItemsWithProtectedAssets = false;
    musicPicker.delegate                      = self;
    musicPicker.allowsPickingMultipleItems    = false;
    musicPicker.prompt                        = NSLocalizedString(@"Select a song", @"Select a song");
    musicPicker.view.frame                    = musicPickerView.bounds;
    [self addChildViewController:musicPicker];
    [musicPickerView addSubview:musicPicker.view];
    [self.view addSubview:musicPickerView];
    [musicPicker didMoveToParentViewController:self];
    [self fadeInMusicPicker:true];

完全不调用委托。没有显示日志，只有本机警报。

我正在获取本机替代品

内部错误

找不到所请求的应用程序扩展名

[取消]

注2

[Apple音乐应用未安装在该设备上，这似乎是一个问题。有人知道一种可靠的方法来确定是否安装了Apple Music应用吗？

Answer 1

您是否在info.plist中设置了媒体库的权限？NSAppleMusicUsageDescription

Answer 2

[似乎Apple的Music应用必须安装在该设备上。仍然不能100％重现，但是安装了该应用程序后，我再也没有看到该问题。

Answer 3

从iOS 13 MPMediaPicker起需要用户授权，这与早期的iOS版本不同。因此，您需要先处理身份验证，然后在用户授予许可后显示选择器。您的代码如下，

MPMediaLibraryAuthorizationStatus authorizationStatus = MPMediaLibrary.authorizationStatus;

    switch (authorizationStatus)
    {
        case MPMediaLibraryAuthorizationStatusAuthorized:
        {
            [self showPickerView];
            break;
        }
        case MPMediaLibraryAuthorizationStatusNotDetermined:
        {
            // Not yet authorized - request it from the system
            [MPMediaLibrary requestAuthorization:^(MPMediaLibraryAuthorizationStatus authorizationStatus)
             {
                 if ( authorizationStatus == MPMediaLibraryAuthorizationStatusAuthorized )
                 {
                     dispatch_async(dispatch_get_main_queue(), ^{

                            [self showPickerView];

                        });
                 }
                 else
                 {
                     PLog(@"The Media Library was not authorized by the user");

                 }
             }];
            break;
        }

        case MPMediaLibraryAuthorizationStatusRestricted:
        case MPMediaLibraryAuthorizationStatusDenied:
        {
            // user has previously denied access. Ask again with our own alert that is similar to the system alert
            // then take them to the System Settings so they can turn it on for the app

            break;
        }
    }


-(void)showPickerView
{
    musicPickerView = [[UIView alloc] initWithFrame:fullScreenRect];
    musicPickerView.alpha = 0.0f;
    musicPicker = [[MPMediaPickerController alloc] initWithMediaTypes:MPMediaTypeMusic];
    musicPicker.showsCloudItems               = false;
    musicPicker.showsItemsWithProtectedAssets = false;
    musicPicker.delegate                      = self;
    musicPicker.allowsPickingMultipleItems    = false;
    musicPicker.prompt                        = NSLocalizedString(@"Select a song", @"Select a song");
    musicPicker.view.frame                    = musicPickerView.bounds;
    [self addChildViewController:musicPicker];
    [musicPickerView addSubview:musicPicker.view];
    [self.view addSubview:musicPickerView];
    [musicPicker didMoveToParentViewController:self];
    [self fadeInMusicPicker:true];
}