UIView 可以设定 autoresizingMask，当它的 superView 尺寸改变时，适应何种变化。

不过 CALayer 却没有这个属性，如和做到让 CALayer 和 UIView 一样？可以这样：

// in ViewController- (void)viewWillLayoutSubviews{    _playerLayer.frame = self.view.bounds;}// in View- (void)layoutSublayersOfLayer:(CALayer *)layer{    _playerLayer.frame = self.bounds;}

 这不是一个好的办法。

当当~

自定义一个 UIView，重写它的 + (Class)layerClass 方法，像这样

@interface RFPlayerLayerView : UIView@end@implementation RFPlayerLayerView+ (Class)layerClass{    return [AVPlayerLayer class];}@end

 使用时设置一些参数，就可以完美拥有 UIView 的 autoresizingMask 的属性了

- （void)setup{    _layerView = [[RFPlayerLayerView alloc] initWithFrame:rect];    _playerLayer = (AVPlayerLayer *)[_layerView layer];    _playerLayer.player = _player;    _playerLayer.videoGravity = AVLayerVideoGravityResizeAspect;    _layerView.autoresizingMask = UIViewAutoresizingFlexibleWidth|UIViewAutoresizingFlexibleHeight;    [self.view addSubview:_layerView];}