UIButton 添加 点击响应区域

按钮图片过小 的时候 ，点击相应的区域就会很小，用户体验就会很差，这个时候就需要添加点击的区域。具体解决办法是重写 category 中UIButton 的 方法

.h 文件：

#import <UIKit/UIKit.h>

 

@interface UIButton (EnlargeTouchArea)

 

- (void)setEnlargeEdgeWithTop:(CGFloat) top right:(CGFloat) right bottom:(CGFloat) bottom left:(CGFloat) left;

 

@end

.m 文件：

#import "UIButton+EnlargeTouchArea.h"

 

@implementation UIButton (EnlargeTouchArea)

 

static char topNameKey;

static char rightNameKey;

static char bottomNameKey;

static char leftNameKey;

 

- (void) setEnlargeEdgeWithTop:(CGFloat) top right:(CGFloat) right bottom:(CGFloat) bottom left:(CGFloat) left

{

    objc_setAssociatedObject(self, &topNameKey, [NSNumber numberWithFloat:top], OBJC_ASSOCIATION_COPY_NONATOMIC);

    objc_setAssociatedObject(self, &rightNameKey, [NSNumber numberWithFloat:right], OBJC_ASSOCIATION_COPY_NONATOMIC);

    objc_setAssociatedObject(self, &bottomNameKey, [NSNumber numberWithFloat:bottom], OBJC_ASSOCIATION_COPY_NONATOMIC);

    objc_setAssociatedObject(self, &leftNameKey, [NSNumber numberWithFloat:left], OBJC_ASSOCIATION_COPY_NONATOMIC);

}

 

- (CGRect) enlargedRect

{

    NSNumber* topEdge = objc_getAssociatedObject(self, &topNameKey);

    NSNumber* rightEdge = objc_getAssociatedObject(self, &rightNameKey);

    NSNumber* bottomEdge = objc_getAssociatedObject(self, &bottomNameKey);

    NSNumber* leftEdge = objc_getAssociatedObject(self, &leftNameKey);

    if (topEdge && rightEdge && bottomEdge && leftEdge)

    {

        return CGRectMake(self.bounds.origin.x - leftEdge.floatValue,

                          self.bounds.origin.y - topEdge.floatValue,

                          self.bounds.size.width + leftEdge.floatValue + rightEdge.floatValue,

                          self.bounds.size.height + topEdge.floatValue + bottomEdge.floatValue);

    }

    else

    {

        return self.bounds;

    }

}

 

- (UIView*) hitTest:(CGPoint) point withEvent:(UIEvent*) event

{

    CGRect rect = [self enlargedRect];

    if (CGRectEqualToRect(rect, self.bounds))

    {

        return [super hitTest:point withEvent:event];

    }

    return CGRectContainsPoint(rect, point) ? self : nil;

}

 

@end