如何更新MPNowPlayingInfoCenter在後臺和AVQueuePlayer中的軌道更改

Question

因此，我試圖更新MPNowPlayingInfoCenter在後臺和AVQueuePlayer中的軌道更改。

在前臺，很容易在

- (id) init{ 
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(didFinish) name:AVPlayerItemDidPlayToEndTimeNotification object:nil]; 

    player = [[AVQueuePlayer alloc]init]; 
    player.actionAtItemEnd = AVPlayerActionAtItemEndPause; 
} 

-(void)didFinish{ 
    [[NSNotificationCenter defaultCenter] removeObserver:self]; 
    // Magic goes here 
    //[[MPNowPlayingInfoCenter defaultCenter] setNowPlayingInfo:nowPlaying]; 
    [player advanceToNextItem]; 
    [player play]; 
} 

在後臺但是沒有AVPlayerActionAtItemEndAdvance它不會去下一個和AVPlayerActionAtItemEndAdvance背景

- (id) init{ 
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(didFinish) name:AVPlayerItemDidPlayToEndTimeNotification object:nil]; 

    player = [[AVQueuePlayer alloc]init]; 
    player.actionAtItemEnd = AVPlayerActionAtItemEndAdvance; 
} 

-(void)didFinish{ //never called 
    [[NSNotificationCenter defaultCenter] removeObserver:self]; 
    // Magic goes here 
    //[[MPNowPlayingInfoCenter defaultCenter] setNowPlayingInfo:nowPlaying]; 
    //play is not needed in this case 
} 

感謝從未來電didFinish！

Answer 1

使用志願：

[self.queuePlayer addObserver:self forKeyPath:@"currentItem" options:NSKeyValueObservingOptionNew context:PlayerItemKVOContext]; 

和

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context { 

    if (context == PlayerItemKVOContext) { 
     AVPlayerItem *playerItem = [_queuePlayer currentItem];