仅捕获 UIView 2 手指 UIPanGestureRecognizer

Posted 2023-03-16

【中文标题】仅捕获 UIView 2 手指 UIPanGestureRecognizer

【英文标题】：Capture only UIView 2 finger UIPanGestureRecognizer

【发布时间】：2013-04-30 13:36:42

【问题描述】：

我的视图控制器中有几个UIScrollViews。我想覆盖一个通过UIPanGestureRecognizer 捕获两指滑动的视图，它不会记录UIScrollView 滑动手势。

当我使用 2 指平移手势在内容上放置透明视图时，未检测到我的点击和 1 指滑动。我尝试覆盖pointInside: 方法以返回NO 但它不会记录我的两指滑动。

效果类似于四指滑动切换应用。

【问题讨论】：

所以希望您的滚动视图不捕获 2 次手指滑动？

@AndyJacobs 你想让滚动视图检测到平移吗？您想添加覆盖层，它将检测 2 个手指平移和滚动视图以检测其他平移，对吗？如果我认为它错了，请澄清它

【参考方案1】：

您不需要叠加视图。 首先实现UIPanGestureRecognizer，它将处理2个手指平移并将其分配给包含UIScrollViews的视图

UIPanGestureRecognizer *panGestureRecognizer = [[UIPanGestureRecognizer alloc]
                                                initWithTarget:self 
                                                        action:@selector(handlePan:)];
panGestureRecognizer.delegate = self;
panGestureRecognizer.minimumNumberOfTouches = 2;
panGestureRecognizer.maximumNumberOfTouches = 2;
[self.view addGestureRecognizer:panGestureRecognizer];

使用UIGestureRecognizerDelegate 以UIScrollView 平移手势处理2 个手指平移

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer
shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer

    return YES;

最后你可以处理 2 个手指平移

- (void)handlePan:(UIPanGestureRecognizer *)gestureRecognizer

    NSLog(@"pan");

如果您想在检测到两个手指平移时停止滚动UIScrollView，您可以禁用和启用UIScrollView 平移识别器

- (void)handlePan:(UIPanGestureRecognizer *)gestureRecognizer

    if(gestureRecognizer.state == UIGestureRecognizerStateBegan)
    
        _scrollView.panGestureRecognizer.enabled = NO;
    
    if(gestureRecognizer.state == UIGestureRecognizerStateEnded)
    
        _scrollView.panGestureRecognizer.enabled = YES;
    
    NSLog(@"pan");

【参考方案2】：

如果您真的不需要覆盖，您可以只使用手势识别器来解决这个问题。我写了这个作为测试：

- (void)viewDidLoad 
    [super viewDidLoad];

    self.scrollView = [[UIScrollView alloc] initWithFrame:self.view.bounds];
    _scrollView.contentSize = CGSizeMake(self.view.bounds.size.width * 2, self.view.bounds.size.height);

    UIView *green = [[UIView alloc] initWithFrame:self.view.bounds];
    [green setBackgroundColor:[UIColor greenColor]];

    UIView *blue = [[UIView alloc] initWithFrame:CGRectOffset(self.view.bounds, self.view.bounds.size.width, 0)];
    [blue setBackgroundColor:[UIColor blueColor]];

    [_scrollView addSubview:green];
    [_scrollView addSubview:blue];

    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingerPan:)];
    [pan setMinimumNumberOfTouches:2];
    [pan setMaximumNumberOfTouches:2];
    [pan setDelaysTouchesBegan:YES];

    [_scrollView addGestureRecognizer:pan];

    [self.view addSubview:_scrollView];


- (void)twoFingerPan:(UIPanGestureRecognizer *)gesture 
    switch (gesture.state) 
        case UIGestureRecognizerStateBegan:
            self.scrollView.scrollEnabled = NO;
            break;
        case UIGestureRecognizerStateCancelled:
        case UIGestureRecognizerStateEnded:
        case UIGestureRecognizerStateFailed:
            self.scrollView.scrollEnabled = YES;
            break;
        default:
            break;
    
    NSLog(@"2 Fingers!");

我收到twoFingerPan: 回电，要求使用 2 根手指。滚动视图的panGestureRecognizer 那时仍在工作，因此我禁用滚动视图上的滚动以处理 2 指平移。我发现这种方法效果很好。一种奇怪的事情是，如果滚动视图正在减速，则不会调用 2 指手势识别器。希望对您有所帮助！