CALayer *viewLayer = someView.layer;
另外CALayer有如一些属性特点:
Layer的大小位置
Layer的背景颜色
Layer的内容
Layer的阴影
Layer的边缘
self.view.layer.backgroundColor = [UIColor orangeColor].CGColor;
self.view.layer.cornerRadius = 20.0f;
self.view.layer.frame = CGRectInset(self.view.layer.frame, 20.0f, 20.0f);