iOS hitTest 机制用处之二-----使用pointInside方法
hittest 机制
下面是伪代码
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event{if (self.hidden == NO || self.alpha < 0.05 || self.userInteractionEnabled == NO) {//1.当满足这几个条件时，直接丢弃touch事件，不再向下分发。return nil;}else{if (![self pointInside:point withEvent:event]) {//2.如果点击point在视图之外，丢弃return nil;}else{//3.分发给子视图if (self.subviews.count > 0) {for (UIView *subView in self.subviews) {UIView *hitTestSubView = [subView hitTest:point withEvent:event];return hitTestSubView;}}else{return self;}}}
}由上面的hittest机制可以知道，如果我们想扩大一个视图的点击范围，或者让一个超出父视图的子视图可以点击，我们既可以通过重写hittest方法实现，即在hittest 方法中去掉pointinside方法的判断，同时也可以通过重写pointinside 方法来实现
重写任何一个方法都可以实现这两种功能
以前写过通过hittest方法来实现的文章 点击这里
所以这里我们只介绍通过重写pointinside 方法分别实现扩大点击范围和超出父视图可以点击
其实不管是重写hittest 或者是 重写point inside ，不管是
扩大点击范围，或者是超出父视图可以点击，本质上都是
修改系统的判断一个点是否在视图的的判断逻辑
重写hittest， 扩大点击范围我们就去掉系统直接掉用pointinside方法，
改为判断扩大后的rect 是否包含point，超出父视图可以点击
我们就直接将point转换为相对于子视图的point，然后让子视图自己掉用hittest, 看是否返回view
代码如下
//
// LBHittestButton.m
// TEXT
//
// Created by mac on 2024/6/1.
// Copyright © 2024 刘博. All rights reserved.
//#import "LBHittestButton.h"@interface LBHittestButton ()@property (nonatomic, strong) UIButton *subButton;@end@implementation LBHittestButton- (instancetype)initWithFrame:(CGRect)frame
{if (self = [super initWithFrame:frame]) {[self addSubview:self.subButton];}return self;
}- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
{CGPoint pointInSubbutton = [self convertPoint:point toView:self.subButton];if ([self.subButton hitTest:pointInSubbutton withEvent:event]) {return [self.subButton hitTest:pointInSubbutton withEvent:event];}CGRect rect = UIEdgeInsetsInsetRect(self.bounds, self.expandEdgeInset);if (CGRectContainsPoint(rect, point)) {return self;}return [super hitTest:point withEvent:event];
}- (void)clickSubButton
{NSLog(@"哈哈哈点击小按钮小按钮");
}#pragma mark - lazy load- (UIButton *)subButton
{if (!_subButton) {_subButton = [UIButton buttonWithType:UIButtonTypeCustom];_subButton.frame = CGRectMake(100, 140, 40, 40);_subButton.backgroundColor = [UIColor redColor];[_subButton addTarget:self action:@selector(clickSubButton) forControlEvents:UIControlEventTouchUpInside];}return _subButton;
}@end重写point inside ，如果是扩大点击范围，我们就判断新的rect是否包含point, 如果是子视图超出父视图可以点击，我们就将point转换为相对于子视图的point，然后判断是否在子视图中
代码如下
//
// LBHittestButton.m
// LBHitTestDemo
//
// Created by mac on 2024/6/2.
//#import "LBHittestButton.h"@interface LBHittestButton ()@property (nonatomic, strong) UIButton *subButton;@end@implementation LBHittestButton- (instancetype)initWithFrame:(CGRect)frame
{if (self = [super initWithFrame:frame]) {[self addSubview:self.subButton];}return self;
}- (void)subButtonClick
{NSLog(@"点击了子视图");
}- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event
{CGPoint point2 = [self convertPoint:point toView:self.subButton];if ([self.subButton pointInside:point2 withEvent:event]) {return YES;}CGRect rect2 = UIEdgeInsetsInsetRect(self.bounds, self.expandEdgeInsets);if (CGRectContainsPoint(rect2, point)) {return YES;}return [super pointInside:point withEvent:event];
}#pragma mark - lazy load- (UIButton *)subButton
{if (!_subButton) {_subButton = [UIButton buttonWithType:UIButtonTypeCustom];_subButton.frame = CGRectMake(100, 200, 40, 40);_subButton.backgroundColor = [UIColor cyanColor];[_subButton addTarget:self action:@selector(subButtonClick) forControlEvents:UIControlEventTouchUpInside];}return _subButton;
}@enddemo链接