AVPlayer 卡顿后缓存好自动播放

• 效果图：

效果图.png

• 问题：利用AVPlayer做网络视频播放时，若此时网络出现问题，AVPlayer会自动将其暂停，而若几分钟网络好时它并不会自动播放，你必须手动调用AVPlayer的播放方法play才会继续播放。

• 解决：所以现在的问题，就是，何时进行AVPlayer的手动让其播放。我们可以AVPlayer提供给我们的属性currentItem的属性值loadedTimeRanges进行监听 视频 缓存大小，当视频缓存大小 > 当前播放时长 ，就 调用AVPlayer的play方法进行播放.

• 实现代码如下：

  • 解析：点击控制器view进行播放网络视频，当开始播放后，你可以模拟 关掉网络，然后会发现 视频播放到缓存时间后，会自动暂停，当你网络打开，AVPlayer默认会继续缓存时，当缓存值 > 当前播放时间，又开始继续播放了。

#import "ViewController.h"
#import 

@interface ViewController ()

/** 播放器 */
@property (nonatomic, strong) AVPlayer *player;

@property (nonatomic, strong) NSString *status_playType; // 正在播放, 等待播放
@property (nonatomic, strong) UILabel *currentTimeLable; // 显示 当前播放时长

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    self.currentTimeLable = [[UILabel alloc ] initWithFrame:CGRectMake(0, 240, self.view.frame.size.width, 400)];
    self.currentTimeLable.backgroundColor = [UIColor greenColor];
    [self.view addSubview:self.currentTimeLable];
}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    if ([keyPath isEqualToString:@"status"]) {
        AVPlayerItemStatus status = [[change objectForKey:NSKeyValueChangeNewKey] integerValue];
        //        NSLog(@"%d", status);
        if (AVPlayerItemStatusReadyToPlay == status) {
            
            
        } else {
            
            
        }
    }else if ([keyPath isEqualToString:@"loadedTimeRanges"]){
        NSTimeInterval timeInterval = [self availableDuration];// 计算缓冲进度
        NSLog(@"已缓存时长 : %f",timeInterval);
        
        self.currentTimeLable.text = [NSString stringWithFormat:@"当前播放时长： %f \\n 已缓存： %f", self.getCurrentPlayingTime, timeInterval];
        
        if (timeInterval > self.getCurrentPlayingTime+5){ // 缓存 大于 播放 当前时长+5
            
            if ([self.status_playType  isEqual: @"等待播放"]) { // 接着之前 播放时长 继续播放
                [self.player play];
                self.status_playType = @"正在播放";
            }
        }else{
            self.status_playType = @"等待播放"; // 出现问题，等待播放
            NSLog(@"等待播放，网络出现问题");
        }
    }
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    [self.player play];
    self.status_playType = @"正在播放";
    
    [[self.player.currentItem valueForKey:@"_playerItem"] addObserver:self forKeyPath:@"status" options:NSKeyValueObservingOptionNew context:nil];
    
    [self.player.currentItem addObserver:self forKeyPath:@"loadedTimeRanges" options:NSKeyValueObservingOptionNew context:nil];// 监听loadedTimeRanges属性
}

#pragma mark - 懒加载代码
- (AVPlayer *)player
{
    if (_player == nil) {
        // 1.创建URL
        NSURL *url = [NSURL URLWithString:@"http://v1.mukewang.com/19954d8f-e2c2-4c0a-b8c1-a4c826b5ca8b/L.mp4"];
        // NSURL *url = [[NSBundle mainBundle] URLForResource:@"01-知识回顾.mp4" withExtension:nil];
        
        // 2.创建AVPlayer对象
        AVPlayerItem *_playerItem = [[AVPlayerItem alloc] initWithURL:url];
        _player = [[AVPlayer alloc] initWithPlayerItem:_playerItem];
        
        // 3.创建播放layer
        AVPlayerLayer *layer = [AVPlayerLayer playerLayerWithPlayer:_player];
        layer.frame = CGRectMake(0, 0, self.view.bounds.size.width, self.view.bounds.size.width * 9 / 16);
        [self.view.layer addSublayer:layer];
    }
    return _player;
}

/**
 *  返回 当前 视频 播放时长
 */
- (double)getCurrentPlayingTime{
    return self.player.currentTime.value/self.player.currentTime.timescale;
}

/**
 *  返回 当前 视频 缓存时长
 */
- (NSTimeInterval)availableDuration{
        NSArray *loadedTimeRanges = [[self.player currentItem] loadedTimeRanges];
        CMTimeRange timeRange = [loadedTimeRanges.firstObject CMTimeRangeValue];// 获取缓冲区域
        float startSeconds = CMTimeGetSeconds(timeRange.start);
        float durationSeconds = CMTimeGetSeconds(timeRange.duration);
        NSTimeInterval result = startSeconds + durationSeconds;// 计算缓冲总进度
       
     return result;
}

@end

• HTTPS处理，相关提示错误：

 App Transport Security has blocked a cleartext HTTP (http://) resource load since it is insecure. Temporary exceptions can be configured via your app's Info.plist file.**

• 注意：HTTPS处理，在Info.plist文件中加入下面代码

    NSAppTransportSecurity
    
        NSAllowsArbitraryLoads