仅捕获UIView 2手指UIPanGestureRecognizer

Question

我的视图控制器中有几个UIScrollView 。 我想覆盖一个通过UIPanGestureRecognizer捕获双指滑动的视图，该视图不会记录UIScrollView滑动手势。

当我使用双指平移手势在我的内容上放置透明视图时，我的水龙头和1个手指滑动未被检测到。 我尝试覆盖pointInside:方法返回NO但是它没有记录我的2指滑动。

效果类似于4指滑动来更改应用程序。

Answer 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UIScrollView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使用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

- (void)handlePan:(UIPanGestureRecognizer *)gestureRecognizer
{
    NSLog(@"pan");
}

如果要在检测到两个手指平移时停止滚动UIScrollView ，可以禁用并启用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");
}

Answer 2

如果你真的不需要叠加，你可以用手势识别器解决这个问题。 我把它写成了一个测试：

- (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!");
}

我得到了twoFingerPan:当使用2个手指时回拨。 滚动视图的panGestureRecognizer仍然在该点工作，因此我禁用滚动视图上的滚动来处理2指平移。 我发现这种方法非常好用。 一种不稳定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。 希望有所帮助！