手势冲突 | gorpeln's Blog

手势冲突主要的三种解决思路：

①设置手势优先级 requireGestureRecognizerToFail:
②阻止手势向事件传递链执行 cancelsTouchesInView、delaysTouchesBegan
③实现协议方法 UIGestureRecognizerDelegate

1、自定义手势优先级

自定义多手势冲突。例如我们设置的单次点击、双击和多指点击手势，需要设置优先识别双击手势，识别失败后再识别单击手势；

 //单指单击
    UITapGestureRecognizer *singleFingerOne = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleSingleFingerEvent:)];
    singleFingerOne.numberOfTouchesRequired = 1; //手指数
    singleFingerOne.numberOfTapsRequired = 1; //tap次数
    [self.view addGestureRecognizer:singleFingerOne];
    
    //单指双击
    UITapGestureRecognizer *singleFingerTwo = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleSingleFingerEvent:)];
    singleFingerTwo.numberOfTouchesRequired = 1;
    singleFingerTwo.numberOfTapsRequired = 2;
    [self.view addGestureRecognizer:singleFingerTwo];
    
    //双指单击
    UITapGestureRecognizer *doubleFingerOne = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleDoubleFingerEvent:)];
    doubleFingerOne.numberOfTouchesRequired = 2;
    doubleFingerOne.numberOfTapsRequired = 1;
    [self.view addGestureRecognizer:doubleFingerOne];
    
    //双指双击
    UITapGestureRecognizer *doubleFingerTwo = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleDoubleFingerEvent:)];
    doubleFingerTwo.numberOfTouchesRequired = 2;
    doubleFingerTwo.numberOfTapsRequired = 2;
    [self.view addGestureRecognizer:doubleFingerTwo];
    
    // 优先级设置
    //如果不加下面的话，当单指双击时，会先调用单指单击中的处理，再调用单指双击中的处理
    [singleFingerOne requireGestureRecognizerToFail:singleFingerTwo];
    //同理双指亦是如此
    [doubleFingerOne requireGestureRecognizerToFail:doubleFingerTwo];

//处理单指事件
- (void)handleSingleFingerEvent:(UITapGestureRecognizer *)sender{
    if (sender.numberOfTapsRequired == 1) {
        //单指单击
        NSLog(@"单指单击");
    }else if(sender.numberOfTapsRequired == 2){
        //单指双击
        NSLog(@"单指双击");
    }
}

//处理双指事件
- (void)handleDoubleFingerEvent:(UITapGestureRecognizer *)sender{
    if (sender.numberOfTapsRequired == 1) {
        //双指单击
        NSLog(@"双指单击");
    }else if(sender.numberOfTapsRequired == 2){
        //双指双击
        NSLog(@"双指双击");
    }
}

2、阻止手势向响应链传递执行

当自定义手势和系统手势冲突，可以使用手势的两个属性：cancelsTouchesInView、delaysTouchesBegan进行处理。

cancelsTouchesInView（是否取消向事件响应链传递）：
默认 YES，自定义的手势响应后，系统手势不再响应，但自定义手势识别前，会先执行系统手势。设置为 NO 后，自定义手势和系统手势会同时识别响应。
delaysTouchesBegan（延迟响应链的识别）：
默认 NO，先执行响应链中的方法（系统方法），识别到自定义手势后，不再执行系统方法。设置为 YES 后，优先识别自定义手势，当自定义手势识别失败后才会响应系统方法

    UIView *testView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, 300)];
    testView.backgroundColor = [UIColor yellowColor];
    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tap:)];
    // 阻止手势向事件传递链执行 默认是 YES
    tap.cancelsTouchesInView = NO;
    [testView addGestureRecognizer:tap];
    [self.view addSubview:testView];
    
    UIButton *testBtn = [UIButton buttonWithType:UIButtonTypeCustom];
    testBtn.frame = CGRectMake(0, 0, 100, 100);
    testBtn.backgroundColor = [UIColor cyanColor];
    [testBtn addTarget:self action:@selector(testBtnClick) forControlEvents:UIControlEventTouchUpInside];
    [testView addSubview:testBtn];

- (void)tap:(UITapGestureRecognizer *)sender{
    NSLog(@"点击view");
}

-(void)testBtnClick{
    NSLog(@"点击button");
}

3、实现协议方法 UIGestureRecognizerDelegate 控制手势冲突

//手指触摸屏幕后回调的方法，返回NO则不再进行手势识别，方法触发等
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch;
//开始进行手势识别时调用的方法，返回NO则结束，不再触发手势
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer;
//是否支持多时候触发，返回YES，则可以多个手势一起触发方法，返回NO则为互斥
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer;
//下面这个两个方法也是用来控制手势的互斥执行的
//这个方法返回YES，第一个手势和第二个互斥时，第一个会失效
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRequireFailureOfGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer NS_AVAILABLE_IOS(7_0);
//这个方法返回YES，第一个和第二个互斥时，第二个会失效
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldBeRequiredToFailByGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer NS_AVAILABLE_IOS(7_0);

常用的是第二个协议方法

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(nonnull UIGestureRecognizer *)otherGestureRecognizer {
    UIPanGestureRecognizer *ges = (UIPanGestureRecognizer *)otherGestureRecognizer;
    
    if ([ges isKindOfClass:NSClassFromString(@"BMKTapDetectingView")]) {
        return NO;
    }
    if([ges isKindOfClass:[UICollectionViewCell class]]){
        return NO;
    }
    // 手势是 UIScrollViewPan 且 可以左右滑动, 已经滑到最左端
    if ([ges isKindOfClass:NSClassFromString(@"UIScrollViewPanGestureRecognizer")]) {
        return [ges.view isKindOfClass:[UIScrollView class]]
        && (((UIScrollView *)ges.view).contentSize.width > ges.view.bounds.size.width * 1.5)
        && (((UIScrollView *)ges.view).contentOffset.x == 0);
    }
    // 手势不是 UIPanGestureRecognizer
    if (![ges isKindOfClass:[UIPanGestureRecognizer class]]) {
        return NO;
    }
    // 手势落点在屏幕左边1/3
    if ([ges locationInView:nil].x <= [UIScreen mainScreen].bounds.size.width / 3) {
        return NO;
    }
    // 手势是 上下滑动
    CGPoint offset = [ges translationInView:nil];
    if (fabs(offset.x) <= fabs(offset.y)) {
        return NO;
    }
    // 默认
    return YES;
}