Add a shadow to the rounded corner Image

It is easy to display the UIView rounded corner. Only three lines of code are required.
CALayer * layer = [avatarImageView layer];
[Layer setMasksToBounds: YES];
[Layer setCornerRadius: 9.0];
 
However, if you add a shadow to a rounded view, the traditional method of adding a shadow is not feasible,
The traditional method is:
AvatarImageView. layer. shadowColor = [UIColor blackColor]. CGColor;
AvatarImageView. layer. shadowOffset = CGSizeMake (0, 1 );
AvatarImageView. layer. shadowOpacity = 1;
 
Because setMasksToBounds indicates that the content outside the frame is reduced, only the content in the frame can be displayed. Since the shadow added by this method is outside the frame, it is dropped.
The traditional method does not work, so we can put the avatarImageView of the rounded corner into a UIView with the same size as it, so that the view has a shadow, and the effect looks the same.
CGRect rect;
Rect = CGRectMake (0, 0, 48, 48 );
AvatarImageView = [[UIImageView alloc] initWithFrame: rect];
AvatarImageView. image = [UIImage imageNamed: @ "test.png"];
 
// Round the corners
CALayer * layer = [avatarImageView layer];
[Layer setMasksToBounds: YES];
[Layer setCornerRadius: 9.0];
 
// Add a shadow by wrapping the avatar into a container
UIView * shadow = [[UIView alloc] initWithFrame: rect];
AvatarImageView. frame = CGRectMake (0, 0, rect. size. width, rect. size. height );
 
// Setup shadow layer and corner
Shadow. layer. shadowColor = [UIColor grayColor]. CGColor;
Shadow. layer. shadowOffset = CGSizeMake (0, 1 );
Shadow. layer. shadowOpacity = 1;
Shadow. layer. shadowRadius = 9.0;
Shadow. layers. cornerRadius = 9.0;
Shadow. clipsToBounds = NO;
 
// Combine the views
[Shadow addSubview: avatarImageView];