CALayer: autoresizingMask

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];
}