IOS 扩大UIButton 响应面积

UIButton+EnlargeTouchArea.h 文件

//
//  UIButton+EnlargeTouchArea.h
//  BtnClickDemo
//
//  Created by apple on 2018/6/8.
//  Copyright © 2018年 wxp. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface UIButton (EnlargeTouchArea)

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

//
//  UIButton+EnlargeTouchArea.m
//  BtnClickDemo
//
//  Created by apple on 2018/6/8.
//  Copyright © 2018年 wxp. 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;


/**
 *  向按钮的四个方向延伸响应面积
 *
 *  @param top    上间距
 *  @param left   左间距
 *  @param bottom 下间距
 *  @param right  右间距
 */
- (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);
}

//获取当前的响应rect
- (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;
    }
}

//系统方法重载
- (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

viewController.m

//
//  ViewController.m
//  BtnClickDemo
//
//  Created by apple on 2018/6/8.
//  Copyright © 2018年 wxp. All rights reserved.
//

#import "ViewController.h"
#import "UIButton+EnlargeTouchArea.h"
@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    [self.button setEnlargeEdgeWithTop:60 right:80 bottom:100 left:100];
    // Do any additional setup after loading the view, typically from a nib.
}


- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (IBAction)btnClick:(id)sender {
    NSLog(@"点击");
}

@end

objc_setAssociatedObject 关联对象

objc_setAssociatedObject 相当于 setValue:forKey 进行关联value对象;

• key：要保证全局唯一，key与关联的对象是一一对应关系。必须全局唯一。通常用@selector(methodName)作为key。
• value：要关联的对象。
• policy：关联策略。有五种关联策略。
• OBJC_ASSOCIATION_ASSIGN 等价于 @property(assign)。
• OBJC_ASSOCIATION_RETAIN_NONATOMIC等价于 @property(strong, nonatomic)。
• OBJC_ASSOCIATION_COPY_NONATOMIC等价于@property(copy, nonatomic)。
• OBJC_ASSOCIATION_RETAIN等价于@property(strong,atomic)。
• OBJC_ASSOCIATION_COPY等价于@property(copy, atomic)。