iOS 视频播放(AVPlayer)的使用

小记:很久没有用系统播放器,都快忘没了.整理下,好记住
要实现系统视频播放的功能,就是使用下面的3个类,缺一不可.

AVPlayerItem:继承NSObject,可以理解为一个模型,里面有很多视频的信息,时间,播放状态,设置播放的连接,等等功能.
AVPlayer:播放器对象.播放,暂停,设置PlayerItem,时间监听的回调(addPeriodicTimeObserverForInterval),设置快进拖拽等方法(seekToTime)
AVPlayerLayer:播放器的占位layer

一:基本的播放功能

使用这三个类能实现最基本的播放功能,添加进度条,播放暂停按钮,调节声音大小,都需要自己去添加.

#import <AVFoundation/AVFoundation.h>
@property (nonatomic, strong) AVPlayerItem      *playItem;
@property (nonatomic, strong) AVPlayerLayer     *playerLayer;
@property (nonatomic, strong) AVPlayer          *player;

//
_playItem = [[AVPlayerItem alloc] initWithURL:[NSURL URLWithString:urlStr]];
self.player = [[AVPlayer alloc] initWithPlayerItem:_playItem];
_playerLayer = [AVPlayerLayer playerLayerWithPlayer:_player];
 _playerLayer.frame = CGRectMake(0, 0, [UIScreen mainScreen].bounds.size.width, 211);
//视频在AvPlayerLayer中的显示方式
_playerLayer.videoGravity = AVLayerVideoGravityResizeAspect;
[self.view.layer addSublayer:_playerLayer];

//再调用播放,最好通过监听播放器的status为AVPlayerStatusReadyToPlay再开始播放
[_player play];

二:细节处理

这里只做了一个播放状态的监听

//播放完成的通知,用于循环播放等功能
 [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(playDidFinish) name:AVPlayerItemDidPlayToEndTimeNotification object:self.player.currentItem];
//监听播放状态
[self.playItem addObserver:self forKeyPath:@"status" options:NSKeyValueObservingOptionNew context:nil];
//不用的时候移除监听
[self.playItem removeObserver:self forKeyPath:@"status"];

#pragma mark -------播放属性监听--------
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSString *,id> *)change context:(void *)context {
    if ([keyPath isEqualToString:@"status"]) {
        switch (self.playItem.status) {
            case AVPlayerStatusUnknown:
                NSLog(@"KVO：未知状态，此时不能播放");
                break;
            case AVPlayerStatusReadyToPlay:
                if (!_player.timeControlStatus || _player.timeControlStatus != AVPlayerTimeControlStatusPaused) {
                    [_player play];
                }
                NSLog(@"KVO：准备完毕，可以播放");
                break;
            case AVPlayerStatusFailed:
                NSLog(@"KVO：加载失败，网络或者服务器出现问题");
                break;
            default:
                break;
        }
    }
}