Ios is similar to WeChat red dot display, and ios is similar to display

Ios is similar to the red dot display function, and ios is similar to the display function.

Design Concept: Add a category to UIView. All views can be highlighted in red as needed.

# Import <UIKit/UIKit. h> @ interface UIView (CHRRedDot) @ property (readonly, nonatomic) CALayer * chr_redDotLayer;/** the distance between the center of the red dot and each edge. If the distance is <= 0, the distance */@ property (nonatomic, assign) UIEdgeInsets chr_redDotEdgeInsets;/** indicates the radius of the red dot. The default value is 4 */@ property (nonatomic, assign) CGFloat chr_redDotRadius;/** the color of the red dot. The default value is 0xFF5A5A */@ property (nonatomic, strong) UIColor * chr_redDotColor;/** whether the red dot displays */@ property (nonatomic, assign) BOOL chr_redDotShow; @ end # pragma mark-method-(void) chr_updateRedDot {CALayer * redDot = self. chr_redDotLayer; if (self. chr_r EdDotShow) {if (redDot = nil) {redDot = [CALayer layer]; self. chr_redDotLayer = redDot; [self. layer addSublayer: redDot];} redDot. backgroundColor = self. chr_redDotColor.CGColor; [self chr_layoutRedDot];} else {[redDot removeFromSuperlayer]; self. chr_redDotLayer = nil; }}- (void) chr_layoutRedDot {CALayer * redDot = self. chr_redDotLayer; if (redDot = nil) return; CGFloat radius = self. chr_redD OtRadius; redDot. cornerRadius = radius; UIEdgeInsets edgeInsets = self. chr_redDotEdgeInsets; CGFloat originX sets = edgeInsets. right <= 0? EdgeInsets. left-radius: self. bounds. size. width-edgeInsets. right + radius; CGFloat originY = edgeInsets. bottom <= 0? EdgeInsets. top-radius: self. bounds. size. height-edgeInsets. bottom + radius; CGFloat length = radius * 2; redDot. frame = CGRectMake (originX, originY, length, length );}