ios - 使用Apple Music API播放歌曲不会更新控制中心或锁定屏幕

Question

我正在使用Apple的新Apple Music API制作应用程序。我有一个带有歌曲列表的屏幕，用户可以点击其中的一个来播放。我的代码部分有效。轻击的歌曲将播放，但不会出现在控制中心上。控制中心保持为空，好像什么都没玩。

- (void)viewDidLoad {
    [super viewDidLoad];

    [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
    [self becomeFirstResponder];


    [[[MPRemoteCommandCenter sharedCommandCenter] playCommand] addTargetWithHandler:^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent * _Nonnull event) {
        NSLog(@"play");
        return MPRemoteCommandHandlerStatusSuccess;
    }];
    [[[MPRemoteCommandCenter sharedCommandCenter] pauseCommand] addTargetWithHandler:^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent * _Nonnull event) {
        NSLog(@"pause");
        return MPRemoteCommandHandlerStatusSuccess;

    }];

    [[[MPRemoteCommandCenter sharedCommandCenter] stopCommand] addTargetWithHandler:^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent * _Nonnull event) {
        return MPRemoteCommandHandlerStatusSuccess;

    }];

    [[[MPRemoteCommandCenter sharedCommandCenter] togglePlayPauseCommand] addTargetWithHandler:^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent * _Nonnull event) {
        return MPRemoteCommandHandlerStatusSuccess;

    }];

    [[MPRemoteCommandCenter sharedCommandCenter] playCommand].enabled = YES;
    [[MPRemoteCommandCenter sharedCommandCenter] pauseCommand].enabled = YES;
    [[MPRemoteCommandCenter sharedCommandCenter] stopCommand].enabled = YES;
    [[MPRemoteCommandCenter sharedCommandCenter] togglePlayPauseCommand].enabled = YES;

    AVAudioSession *audioSession = [AVAudioSession sharedInstance];
    [audioSession setCategory:AVAudioSessionCategoryPlayback error:nil];
    [audioSession setActive:YES error:nil];
}

```

当点击一个单元格时:

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
MPMusicPlayerApplicationController *controller = [MPMusicPlayerController applicationQueuePlayer];
[controller performQueueTransaction:^(MPMusicPlayerControllerMutableQueue * _Nonnull queue) {

    MPMusicPlayerStoreQueueDescriptor *queueDescripter = [[MPMusicPlayerStoreQueueDescriptor alloc] initWithStoreIDs:@[_album.songs[indexPath.row].identifier]];
    [queue insertQueueDescriptor:queueDescripter afterItem:nil];
} completionHandler:^(MPMusicPlayerControllerQueue * _Nonnull queue, NSError * _Nullable error) {
    [controller setNowPlayingItem:queue.items[0]];
    [controller prepareToPlay];
    [controller play];

    MPMediaItem *item = [controller nowPlayingItem];

    NSDictionary *info = @{MPMediaItemPropertyAlbumTitle:item.albumTitle, MPMediaItemPropertyArtist:album.artistName, MPMediaItemPropertyTitle:item.title, MPMediaItemPropertyArtwork:item.artwork, MPMediaItemPropertyPlaybackDuration:@(item.playbackDuration), MPNowPlayingInfoPropertyElapsedPlaybackTime:@0};
    [[MPNowPlayingInfoCenter defaultCenter] setNowPlayingInfo:info];
}];

}

此外，此消息还将记录到控制台。我不确定这是否与此问题有关。 [RemoteControl] Error setting active player: (null)

Answer 1

尝试使用Apple's sample code，只要使用applicationQueuePlayer，我就会观察到相同的行为。使用systemMusicPlayer可使代码按您期望的方式工作，从而更新Control Center。