iOS 圆角阴影的处理方法

第一种，固定大小的view，采用CALayer处理阴影问题。

UIView *v= [[UIView alloc] initWithFrame:CGRectMake(100, 100, 200, 200)];

v.backgroundColor = [UIColor whiteColor];

[self.view addSubview:v];

UIView *subView = [[UIView alloc] initWithFrame:CGRectMake(50, 50, 100, 100)];

subView.backgroundColor = [UIColor whiteColor];

subView.layer.cornerRadius = 15.f;

subView.clipsToBounds = YES;

CALayer *layer = [CALayer layer];

layer.frame = subView.frame;

layer.backgroundColor = [UIColor whiteColor].CGColor;

layer.shadowOffset = CGSizeMake(3, 3);

layer.shadowColor = [UIColor lightGrayColor].CGColor;

layer.cornerRadius = 15.f;

layer.shadowOpacity = 0.6;

[v.layer addSublayer:layer];

[v addSubview:subView];

这种方式，经常在处理imageView的圆角和阴影时采用上述的方式。

第二种方式，对UIView单独做处理。

UIView *v=[[UIView alloc]initWithFrame:CGRectMake(10, 10, 100, 100)];

v.backgroundColor=[UIColor yellowColor];

//v.layer.masksToBounds=YES;这行去掉

v.layer.cornerRadius=10;

v.layer.shadowColor=[UIColor redColor].CGColor;

v.layer.shadowOffset=CGSizeMake(10, 10);

v.layer.shadowOpacity=0.5;

v.layer.shadowRadius=5;

[self.view addSubview:v];

这种方法一定不能设置view的clipToBounds。