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我有一个超级奇怪的问题。我正在使用 iOS13MPMediaPickerController从用户苹果音乐库中获取一些歌曲，以便通过[MPMusicPlayerController applicationMusicPlayer].

现在，我已将一些播放列表中的一些未下载歌曲添加到我的库中，委托功能

- (void)mediaPicker:(MPMediaPickerController *)mediaPicker didPickMediaItems:(MPMediaItemCollection *)mediaItemCollection

返回

mediaItemCollection.items.firstObject

MPModelObjectMediaItem玩家无法播放的类型的对象。（我也不能转换为那种类型，因为它是未知的。也没有这种类型的文档。它似乎是媒体播放器框架内的一个私有类。）

我期待MPConcreteMediaItem所有下载的类型（以及不在播放列表中的所有其他云项目）

选择器是这样配置的

musicPicker = [[MPMediaPickerController alloc] initWithMediaTypes:MPMediaTypeMusic];
musicPicker.showsCloudItems               = true;
musicPicker.showsItemsWithProtectedAssets = true;
musicPicker.delegate                      = self;
musicPicker.allowsPickingMultipleItems    = false;

有什么提示吗？

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1 回答 1

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好吧，如果您没有将它们添加到您的音乐库中，您加载到您自己的应用程序中的项目似乎无法正确加载。(iOS13.3)

我正在使用这个解决方法：

- (void)mediaPicker:(MPMediaPickerController *)mediaPicker didPickMediaItems:(MPMediaItemCollection *)mediaItemCollection
{
    assert(mediaItemCollection.count == 1);
    // this check is done because it seems that in the following scenario you dont get a
    // MPConcreteMediaItem which can be played. Instead you get a MPModelObjectMediaItem
    // this happens when an item was selected that is inside a playlist, but does not belong
    // to your library (nor is it downloaded to your device)
    if(mediaItemCollection.items.firstObject.persistentID <= 0)
    {
        UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"Song Not Added")
                                                                message:@"This song must be added to your Apple Music library. Please add the song to your library from the Music App."
                                                                preferredStyle:UIAlertControllerStyleAlert];
        [alertController addAction:[UIAlertAction actionWithTitle:@"Dismiss"
                                                  style:UIAlertActionStyleDefault
                                                  handler:nil]];
        [alertController addAction:[UIAlertAction actionWithTitle:@"Open Music App"
                                                  style:UIAlertActionStyleCancel
                                                  handler:^(UIAlertAction *alertAction)
                                                  {
                                                      [[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"music://"]
                                                                      options:nil
                                                                      completionHandler:nil];
                                                  }]];
        [self presentViewController:alertController animated:true completion:nil];
        return;
    }
    // good to go? then load it
    [musicPlayer setQueueWithItemCollection:mediaItemCollection];
    ...
}
于 2020-01-25T09:44:23.830 回答