iOS之UIButton扩大按钮的响应区域

在开发中有时会遇见设计图里按钮设计的特别小，这时会用到手动扩大UIButton的响应范围，下面有两个解决办法：

第一种方法：创建一个类目：UIButton+EnlargeTouchArea

.h文件

#import <UIKit/UIKit.h>

@interface UIButton (EnlargeTouchArea)

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

- (void)setEnlargeEdge:(CGFloat) size;

@end

.m文件

//
//  UIButton+EnlargeTouchArea.m
//  HeBeiFM
//
//  Created by Apple on 16/4/27.
//  Copyright © 2016年 Apple. All rights reserved.
//

#import "UIButton+EnlargeTouchArea.h"
#import <objc/runtime.h>

@implementation UIButton (EnlargeTouchArea)

static char topNameKey;
static char rightNameKey;
static char bottomNameKey;
static char leftNameKey;

- (void)setEnlargeEdge:(CGFloat) size
{
    objc_setAssociatedObject(self, &topNameKey, [NSNumber numberWithFloat:size], OBJC_ASSOCIATION_COPY_NONATOMIC);
    objc_setAssociatedObject(self, &rightNameKey, [NSNumber numberWithFloat:size], OBJC_ASSOCIATION_COPY_NONATOMIC);
    objc_setAssociatedObject(self, &bottomNameKey, [NSNumber numberWithFloat:size], OBJC_ASSOCIATION_COPY_NONATOMIC);
    objc_setAssociatedObject(self, &leftNameKey, [NSNumber numberWithFloat:size], OBJC_ASSOCIATION_COPY_NONATOMIC);
}

- (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

使用方法：

    UIButton *button = [UIButton new];
    [button setEnlargeEdge:];
    //或者
    [button setEnlargeEdgeWithTop: right: bottom: left:];

第二种：直接创建一个UIButton类，然后复写pointInside方法

使用时继承于此类即可

.h文件

#import <UIKit/UIKit.h>

@interface BiggerClickAreaButton : UIButton

@end

.m文件

#import "BiggerClickAreaButton.h"

@implementation BiggerClickAreaButton

- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent*)event
{
    CGRect bounds = self.bounds;
    //若原热区小于44x44，则放大热区，否则保持原大小不变
    CGFloat widthDelta = MAX(44.0 - bounds.size.width, );
    CGFloat heightDelta = MAX(44.0 - bounds.size.height, );
    bounds = CGRectInset(bounds, -0.5 * widthDelta, -0.5 * heightDelta);
    return CGRectContainsPoint(bounds, point);
}

@end

使用时直接继承创建即可