iOS，当音乐变化时，请阅读标题音乐iPod

Question

我想从iPod Music中获取iPod音乐的名称和艺术家名称但是我想要当音乐更改时，我可以检测到uilabel的变化

这是代码：

 - (IBAction)getTitlemusic
{
   // MPMediaItem * currentItem = self.musicPlayer.nowPlayingItem;

    MPMediaItem * song = [[MPMusicPlayerController iPodMusicPlayer] nowPlayingItem];
    NSString * album = [song valueForProperty:MPMediaItemPropertyAlbumTitle];
    NSString * title = [song valueForProperty:MPMediaItemPropertyTitle];
    NSString * artist = [song valueForProperty:MPMediaItemPropertyArtist];

    NSLog(@"%@,%@,%@", album,title,artist);
    songlabel.text = [NSString stringWithFormat:@"%@",album ];
    arttistlabel.text =  [NSString stringWithFormat:@"%@r%@",title,artist];

      [self performSelector:@selector(getTitlemusic) withObject:nil afterDelay:10.0f];
}

我知道计时器和延迟不是很好的主意

Answer 1

MPMusicPlayerController *player = [MPMusicPlayerController iPodMusicPlayer];
[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(getTitlemusic)
                                             name:MPMusicPlayerControllerNowPlayingItemDidChangeNotification
                                           object:player];
[player beginGeneratingPlaybackNotifications];

使用此代码