获取沙盒目录
//获取沙盒目录带（Documents）
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths firstObject];
NSString *fullPath = [NSString stringWithFormat:@"%@/%@", documentsDirectory, @"video-test.mp4"];
//NSHomeDirectory() 与 documentsDirectory少（/Documents）
NSString *fullPath = [NSString stringWithFormat:@"%@/Documents/%@", NSHomeDirectory(), @"video-test.mp4"];
//
获取本地文件（自己理解就是项目里的文件）
NSString *fullPath = [[NSBundle mainBundle] pathForResource:@"video_test" ofType:@"mp4"];
播放视频
NSURL *url = [NSURL URLWithString:urlStr];
// 播放本来视频
// NSURL *url = [NSURL fileURLWithPath:fullPath];
/// 视频播放器
_videoPlayer = [AVPlayer playerWithURL:url];
/// 视频播放渲染图层
AVPlayerLayer *videoLayer = [AVPlayerLayer playerLayerWithPlayer:_videoPlayer];
[videoLayer setVideoGravity:AVLayerVideoGravityResizeAspect];//显示模式
[videoLayer setBounds:self.bounds];
[videoLayer setPosition:CGPointMake(self.width * 0.5, self.height * 0.5)];
[self.layer addSublayer:videoLayer];
