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ios扩大按钮的点击区域

ios扩大按钮的点击区域

作者: 快乐的tomato | 来源:发表于2017-08-24 11:25 被阅读124次

    面试的时候,有一次被问到怎样扩大Button的点击区域,当时回答的不是让面试官很满意,现在来总结一下。
    在网上看了很多的方法,最后看到一篇关于用Rutime机制来实现的方法,真的很好用 参考文章
    话不多说,上代码
    一、创建一个button的分类
    button.h文件

    #import <UIKit/UIKit.h>
    #import <objc/runtime.h>
    
    @interface UIButton (ExpandTheClickArea)
    
    - (void)setEnlargeEdge:(CGFloat) size;
    
    - (void)setEnlargeEdgeWithTop:(CGFloat) top right:(CGFloat) right bottom:(CGFloat) bottom left:(CGFloat) left;
    
    @end
    
    

    button.m文件

    #import "UIButton+ExpandTheClickArea.h"
    
    @implementation UIButton (ExpandTheClickArea)
    
    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
    
    

    实现

    #import "ViewController.h"
    #import "UIButton+ExpandTheClickArea.h"
    @interface ViewController ()
    
    @end
    
    @implementation ViewController
    
    - (void)viewDidLoad {
        [super viewDidLoad];
       
        UIButton *btnCancel = [UIButton buttonWithType:UIButtonTypeCustom];
        
        btnCancel.frame = CGRectMake(100, 100, 10, 10);
        
        btnCancel.backgroundColor = [UIColor redColor];
        
        //在此可以随意设置button上下左右的点击范围
        [btnCancel setEnlargeEdgeWithTop:10 right:10 bottom:10 left:0];
        
        [btnCancel addTarget:self action:@selector(ExpandTheArea) forControlEvents:UIControlEventTouchUpInside];
        
        [self.view addSubview:btnCancel];
    }
    -(void)ExpandTheArea{
    
          NSLog(@"哈哈");
    }
    @end
    
    二、什么是objc_setAssociatedObject

    iOS objc_setAssociatedObject 关联对象的学习

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