[self treeLayers];
- (void)treeLayers {
//图层的树状结构
UIView *layerV = [[UIView alloc] init];
layerV.frame = CGRectMake(20.0f, 20.0f, 200.0f, 200.0f);
layerV.backgroundColor = [UIColor redColor];
[self.view addSubview:layerV];
CALayer *blueLayer = [CALayer layer];
blueLayer.frame = CGRectMake(50.0f, 50.0f, 100.0f, 100.0f);
blueLayer.backgroundColor = [[UIColor blueColor] CGColor];
[layerV.layer addSublayer:blueLayer];
}
