iOS之UIButton擴大按鈕的響應區域

在開發中有時會遇見設計圖裡按鈕設計的特別小，這時會用到手動擴大UIButton的響應範圍，下麵有兩個解決辦法：

第一種方法：創建一個類目：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:20];
    //或者
    [button setEnlargeEdgeWithTop:20 right:20 bottom:20 left:20];

第二種：直接創建一個UIButton類，然後覆寫pointInside方法

使用時繼承於此類即可

.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;
    //若原熱區小於44x44，則放大熱區，否則保持原大小不變
    CGFloat widthDelta = MAX(44.0 - bounds.size.width, 0);
    CGFloat heightDelta = MAX(44.0 - bounds.size.height, 0);
    bounds = CGRectInset(bounds, -0.5 * widthDelta, -0.5 * heightDelta);
    return CGRectContainsPoint(bounds, point);
}
 
 
@end

使用時直接繼承創建即可