NSURL * url = [NSURL URLWithString:self.currentSong.url];
AVPlayerItem * songItem = [[AVPlayerItem alloc]initWithURL:url];
AVPlayer * player = [[AVPlayer alloc]initWithPlayerItem:songItem];

AVPlayer * player = [[AVPlayer alloc] initWithURL:url];

AVPlayerItem * songItem = player.currentItem;

[player play];

[player pause];

[player replaceCurrentItemWithPlayerItem:songItem];

NSArray * items = @[item1, item2, item3 ....];
AVQueuePlayer * queuePlayer = [[AVQueuePlayer alloc]initWithItems:items];

id timeObserve = [self.player addPeriodicTimeObserverForInterval:CMTimeMake(1.0, 1.0) queue:dispatch_get_main_queue() usingBlock:^(CMTime time) {
  float current = CMTimeGetSeconds(time);  
  float total = CMTimeGetSeconds(songItem.duration);  
  if (current) {   
    weakSelf.progress = current / total;   
    weakSelf.playTime = [NSString stringWithFormat:@"%.f",current];   
    weakSelf.playDuration = [NSString stringWithFormat:@"%.2f",total];  }
 }];

if (timeObserve) {
  [player removeTimeObserver:_timeObserve];
  timeObserve = nil;
 }

[songItem addObserver:self forKeyPath:@"status" options:NSKeyValueObservingOptionNew context:nil];

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

 if ([keyPath isEqualToString:@"status"]) {
  switch (self.player.status) {   
   case AVPlayerStatusUnknown:    
    BASE_INFO_FUN(@"KVO：未知状态，此时不能播放");    
    break;   
   case AVPlayerStatusReadyToPlay:    
    self.status = SUPlayStatusReadyToPlay;     
    BASE_INFO_FUN(@"KVO：准备完毕，可以播放");    
    break;
   case AVPlayerStatusFailed:
    BASE_INFO_FUN(@"KVO：加载失败，网络或者服务器出现问题");
    break;   
   default:    
    break;  
  }
 }
}

[songItem removeObserver:self forKeyPath:@"status"];

[songItem addObserver:self forKeyPath:@"loadedTimeRanges" options:NSKeyValueObservingOptionNew context:nil];

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSString *,id> *)change context:(void *)context { 
 AVPlayerItem * songItem = object;
 if ([keyPath isEqualToString:@"loadedTimeRanges"]) {
  NSArray * array = songItem.loadedTimeRanges;  
  CMTimeRange timeRange = [array.firstObject CMTimeRangeValue]; //本次缓冲的时间范围
  NSTimeInterval totalBuffer = CMTimeGetSeconds(timeRange.start) + CMTimeGetSeconds(timeRange.duration); //缓冲总长度
  SuLog(@"共缓冲%.2f",totalBuffer);
 }
}

[songItem removeObserver:self forKeyPath:@" loadedTimeRanges"];

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(playbackFinished:) name:AVPlayerItemDidPlayToEndTimeNotification object:songItem];
- (void)playbackFinished:(NSNotification *)notice { 
 BASE_INFO_FUN(@"播放完成"); 
 [self playNext];
}

[[NSNotificationCenter defaultCenter] removeObserver:self];

[[UIApplication sharedApplication] beginReceivingRemoteControlEvents];

- (BOOL)canBecomeFirstResponder { 
 return YES;
}

- (void)remoteControlReceivedWithEvent:(UIEvent *)event {  
 switch (event.subtype) {  
  case UIEventSubtypeRemoteControlPlay:
   [self.player startPlay];
   BASE_INFO_FUN(@“remote_播放");
   break;  
  case UIEventSubtypeRemoteControlPause:   
   [self.player pausePlay];
   BASE_INFO_FUN(@"remote_暂停");
   break;  
  case UIEventSubtypeRemoteControlNextTrack:
   [self.player playNextSong];
   BASE_INFO_FUN(@"remote_下一首");
   break;  
  case UIEventSubtypeRemoteControlTogglePlayPause:   
   self.player.isPlaying ? [self.player pausePlay] : [self.player startPlay];   
   BASE_INFO_FUN(@“remote_耳机的播放/暂停");
   break;  
  default:   
   break; }
}

- (void)configNowPlayingCenter { BASE_INFO_FUN(@"配置NowPlayingCenter");
 NSMutableDictionary * info = [NSMutableDictionary dictionary];
 //音乐的标题
 [info setObject:_player.currentSong.title forKey:MPMediaItemPropertyTitle];
  //音乐的艺术家
 [info setObject:_player.currentSong.artist forKey:MPMediaItemPropertyArtist];
  //音乐的播放时间
 [info setObject:@(self.player.playTime.intValue) forKey:MPNowPlayingInfoPropertyElapsedPlaybackTime];
  //音乐的播放速度
 [info setObject:@(1) forKey:MPNowPlayingInfoPropertyPlaybackRate];
  //音乐的总时间
 [info setObject:@(self.player.playDuration.intValue) forKey:MPMediaItemPropertyPlaybackDuration];
  //音乐的封面
 MPMediaItemArtwork * artwork = [[MPMediaItemArtwork alloc] initWithImage:_player.coverImg];
 [info setObject:artwork forKey:MPMediaItemPropertyArtwork];
  //完成设置
 [[MPNowPlayingInfoCenter defaultCenter]setNowPlayingInfo:info];
}