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别小，這時會用到手動擴大UIButton的響應範圍，下面有兩個解決辦法：

第一種方法：建立一個類目：UIButton+EnlargeTouchArea 

.h檔案

#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檔案

//
//  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：直接建立一個UIButton類，然後複寫pointInside方法

使用時繼承于此類即可

.h檔案

#import <UIKit/UIKit.h>

@interface BiggerClickAreaButton : UIButton

@end
           

.m檔案

#import "BiggerClickAreaButton.h"

@implementation BiggerClickAreaButton

- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent*)event
{
    CGRect bounds = self.bounds;
    //若原熱區小于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
           

使用時直接繼承建立即可