如何阻止从超级视图到子视图的手势？

Question

我正在编写一个模块，每次在视图上滑动时，都会添加两个视图大小为一半的子视图。这些子视图有自己的手势（例如：平移，...）。我第一次刷，没关系，因为没有创建任何子视图。但是一旦创建了子视图，每次我滑动时，滑动手势总是传递给它的子视图。 :(，所以我必须滑动2次才能划分。

我想知道有没有办法阻止滑动传递到它的子视图？谢谢。

更新
我使用 shouldRecognizeSimultaneouslyWithGestureRecognizer 使这些手势同时工作。但是还是有一些问题。父视图有它的滑动手势，子视图有它的平移手势。由于我使用了 souldRecognizeSimultaneouslyWithGestureRecognizer，所以有时在我平移时，会触发滑动手势。那么，您知道在这种情况下如何在 Pan 处于活动状态时禁用 Swipe 吗？

Answer 1

你必须实现 UIGestureRecognizerDelegate 方法：

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

并将您的控制器添加为手势识别器的代表。然后，当两个手势识别器响应一个手势时，将调用此方法，您可以在此处为您的应用实现所需的逻辑。

在控制器的接口声明中你必须输入：

@interface testcViewController () <UIGestureRecognizerDelegate>

那么，在创建手势识别器时：

UISwipeGestureRecognizer *swipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipe)];
swipe.direction = UISwipeGestureRecognizerDirectionDown;
swipe.delegate = self;
[self.view addGestureRecognizer:swipe];

然后，最后，将此方法添加到控制器：

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
    BOOL shouldInteract = NO;
    //Here you decide whether or not the two recognizers whould interact.
    return shouldInteract;
}

编辑 你也可以实现

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer;

在这里，检测您是否已经呈现了子视图，并阻止您想要的任何手势。

Answer 2

为了阻止来自超级视图的所有手势识别器，我创建了一个 UIGestureRecognizer 子类，它在附加到视图时会执行此操作。请参阅以下代码（取自我的 WEPopover 项目）：

#import "WEBlockingGestureRecognizer.h"
#import <UIKit/UIGestureRecognizerSubclass.h>

@implementation WEBlockingGestureRecognizer

- (id)init {
    return [self initWithTarget:self action:@selector(__dummyAction)];
}

- (id)initWithTarget:(id)target action:(SEL)action {
    if ((self = [super initWithTarget:target action:action])) {
        self.cancelsTouchesInView = NO;
    }
    return self;
}

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    if (self.state == UIGestureRecognizerStatePossible) {
        self.state = UIGestureRecognizerStateBegan;
    }
}

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
    self.state = UIGestureRecognizerStateRecognized;
}

- (BOOL)canBePreventedByGestureRecognizer:(UIGestureRecognizer *)preventingGestureRecognizer {
    return [self isGestureRecognizerAllowed:preventingGestureRecognizer];
}

- (BOOL)canPreventGestureRecognizer:(UIGestureRecognizer *)preventedGestureRecognizer {
    return ![self isGestureRecognizerAllowed:preventedGestureRecognizer];
}

- (BOOL)shouldBeRequiredToFailByGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
    return ![self isGestureRecognizerAllowed:otherGestureRecognizer];
}

- (BOOL)shouldRequireFailureOfGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
    return NO;
}

- (BOOL)isGestureRecognizerAllowed:(UIGestureRecognizer *)gr {
    return [gr.view isDescendantOfView:self.view];
}

- (void)__dummyAction {

}

@end

如果您想阻止附加到某个视图的父视图的所有手势识别器，只需执行以下操作：

- (void)blockParentGesturesForView:(UIView *)v {
    [v addGestureRecognizer:[WEBlockingGestureRecognizer new]];
}

Answer 3

将 userinteractionEnabled 设置为子视图的 NO

 subview.userinteractionEnabled=NO

如果您不想禁用 userInteraction，请使用cancelsTouchesInView 方法

cancelsTouchesInView——如果手势识别器识别出它的手势， 它会从他们的视野中解除该手势的剩余触摸（所以 窗口不会提供它们）。窗口取消之前的 使用 (touchesCancelled:withEvent:) 消息传递触摸。如果一个 手势识别器无法识别其手势，视图接收到 多点触摸序列中的所有触摸。

Answer 4

试试这样，

   - (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer{
    return NO;
}

Answer 5

考虑到我有一个dialogView 作为我的UIViewController 的主要view 的直接子视图，我将手势识别器附加到主要view 并执行以下操作（将我的视图控制器设置为手势识别器delegate):

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
    let point = touch.location(in: view)
    return !dialogView.frame.contains(point)
} 

Answer 6

采用我在这里阅读的内容并制作了一个非常棒的 Swift 5（对我来说）！我在一个视图中有一个滑动控件，该控件也有一个用于移动到另一个视图的滑动识别器。如果手指没有碰到滑块的拇指，则整个视图都会移动。

通过将此视图放置在滑块下方（已展开使其更大一些），未命中不会有任何作用。

final class BlockingView: UIView, UIGestureRecognizerDelegate {
    let swipe: UISwipeGestureRecognizer = UISwipeGestureRecognizer();

    init() {
        super.init(frame: CGRect.zero)

        swipe.direction = [.left, .right]
        self.addGestureRecognizer(swipe)
    }
    required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") }

    @objc override func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool { return false }
}

希望这可以为某人省去麻烦！