AVPlayer
AVPlayer播放器存在于AVFoundation中, 能够播放网络和本地视频/音频, 和MediaPlayer.framework框架下的两个播放器不同, 并没有默认的UI界面,是一个高度自定义的播放器。与AVAudioPlayer相比,，AVPlayer可以实现流媒体播放，而AVAudioPlayer只能缓存完再播放。
0.PNG
AVPlayer实现
AVPlayer通过asset来初始化player，当然也可以直接用URL初始化
NSURL *musicURL = [self.tracksVM playURLForRow:_indexPathRow];
AVPlayerItem *currentPlayerItem = [AVPlayerItem playerItemWithURL:musicURL];
_player = [[AVPlayer alloc] initWithPlayerItem:currentPlayerItem];
如果要使用视频播放，需要再添加AVPlayerLayer
//设置播放页面
AVPlayerLayer *layer = [AVPlayerLayer playerLayerWithPlayer:_player];
layer.frame = CGRectMake(0, 0, [UIScreen mainScreen].bounds.size.width, 300);
layer.backgroundColor = [UIColor cyanColor].CGColor;
//设置播放窗口和当前视图之间的比例显示内容
layer.videoGravity = AVLayerVideoGravityResizeAspect;
//添加到self.view
[self.view.layer addSublayer:layer];
1.gif
AVPlayerLayer常用操作
[self.player play];//播放
[self.player pause];//暂停
[self.player seekToTime:CMTimeMake(0, 1)];//改变进度
[self.player.currentItem currentTime]//当前时间
[self.player.currentItem duration]//总时间
self.player.volume = 1.0f;//设置音量
当切换上下首时使用replaceCurrentItemWithPlayerItem方法，可以切换item，但是发现切换时会造成卡顿，后来使用initWithPlayerItem替代解决
[self.player replaceCurrentItemWithPlayerItem:_currentPlayerItem];//切换item
2.gif
监听AVPlayer
通过addPeriodicTimeObserverForInterval：监听进度变化，interval参数为响应的间隔时间，这里设为每秒都响应，queue是队列，传NULL代表在主线程执行。并且可以更新UI，比如进度条的当前时间与音频总长度。
- (id)addPeriodicTimeObserverForInterval:(CMTime)interval queue:(dispatch_queue_t)queue usingBlock:(void (^)
监听AVPlayer是否播放完成，完成后按照当前状态执行操作
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(playbackFinished:) name:AVPlayerItemDidPlayToEndTimeNotification object:[self.player currentItem]];
-(void)playbackFinished:(NSNotification *)notification{
if (_cycle == theSong) {
[self playAgain];
}else if(_cycle == nextSong){
[self playNextMusic];
}else if(_cycle == isRandom){
[self randomMusic];
}
NSLog(@"开始下一首");
[self.delegate changeMusic];
NSMutableDictionary *userInfo = [NSMutableDictionary dictionary];
userInfo[@"coverURL"] = [self.tracksVM coverURLForRow:_indexPathRow];
[[NSNotificationCenter defaultCenter] postNotificationName:@"changeCoverURL" object:nil userInfo:userInfo];
}
设置后台播放，与锁屏时展示歌曲信息控制播放
// 支持后台播放
[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];
// 激活
[[AVAudioSession sharedInstance] setActive:YES error:nil];
// 开始监控
[[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
// 播放信息中心
MPNowPlayingInfoCenter *center = [MPNowPlayingInfoCenter defaultCenter];
// 初始化播放信息
NSMutableDictionary *info = [NSMutableDictionary dictionary];
// 专辑名称
info[MPMediaItemPropertyAlbumTitle] = [self playMusicName];
// 歌手
info[MPMediaItemPropertyArtist] = [self playSinger];
// 歌曲名称
info[MPMediaItemPropertyTitle] = [self playMusicTitle];
// 设置图片
info[MPMediaItemPropertyArtwork] = [[MPMediaItemArtwork alloc] initWithImage:[self playCoverImage]];
// 设置持续时间（歌曲的总时间）
[info setObject:[NSNumber numberWithFloat:CMTimeGetSeconds([self.player.currentItem duration])] forKey:MPMediaItemPropertyPlaybackDuration];
// 设置当前播放进度
[info setObject:[NSNumber numberWithFloat:CMTimeGetSeconds([self.player.currentItem currentTime])] forKey:MPNowPlayingInfoPropertyElapsedPlaybackTime];
// 切换播放信息
center.nowPlayingInfo = info;
3.gif
远程控制事件 Remote Control Event可以在不打开app时，控制音乐播放器播放
// 成为第一响应者（必备条件）
[self becomeFirstResponder];
#pragma mark - 远程控制事件监听
- (BOOL)canBecomeFirstResponder{
return YES;
}
- (void)remoteControlReceivedWithEvent:(UIEvent *)event{
// event.type; // 事件类型
// event.subtype; // 事件的子类型
// UIEventSubtypeRemoteControlPlay = 100,
// UIEventSubtypeRemoteControlPause = 101,
// UIEventSubtypeRemoteControlStop = 102,
// UIEventSubtypeRemoteControlTogglePlayPause = 103,
// UIEventSubtypeRemoteControlNextTrack = 104,
// UIEventSubtypeRemoteControlPreviousTrack = 105,
// UIEventSubtypeRemoteControlBeginSeekingBackward = 106,
// UIEventSubtypeRemoteControlEndSeekingBackward = 107,
// UIEventSubtypeRemoteControlBeginSeekingForward = 108,
// UIEventSubtypeRemoteControlEndSeekingForward = 109,
switch (event.subtype) {
case UIEventSubtypeRemoteControlPlay:
case UIEventSubtypeRemoteControlPause:
[[FYPlayManager sharedInstance] pauseMusic];
break;
case UIEventSubtypeRemoteControlNextTrack:
[[FYPlayManager sharedInstance] nextMusic];
break;
case UIEventSubtypeRemoteControlPreviousTrack:
[[FYPlayManager sharedInstance] previousMusic];
default:
break;
}
}
AVPlayerLayer是流媒体播放，如果要实现边下边缓存，缓存完成下载好文件的话，需要自定义scheme来创建avplayer，在资源的 URL 不能被系统识别时会自定义视频加载，从而使用AVAssetResourceLoaderDelegate
