如果按下子视图的按钮，如何取消 UIGestureRecognizer

Question

我正在努力从手势识别器中获得我想要的行为，特别是如果其他手势被触发则取消某些手势。

我有一个 scrollView 设置为分页和每个页面中的多个子视图。如果用户点击页面的右侧或左侧，我添加了一个触摸手势识别器以滚动到下一页或上一页。

    // Add a gesture recogniser turn pages on a single tap at the edge of a page
    UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapGestureHandler:)];
    tapGesture.cancelsTouchesInView = NO;
    [self addGestureRecognizer:tapGesture];
    [tapGesture release];

还有我的手势处理程序：

- (void) tapGestureHandler:(UIGestureRecognizer *) gestureRecognizer {
    const CGFloat kTapMargin = 180;

    // Get the position of the point tapped in the window co-ordinate system
    CGPoint tapPoint = [gestureRecognizer locationInView:nil];

    // If the tap point is to the left of the page then go back a page
    if (tapPoint.x > (self.frame.size.width - kTapMargin)) [self scrollRectToVisible:pageViewRightFrame animated:YES];

    // If the tap point is to the right of the page then go forward a page
    else if (tapPoint.x < kTapMargin) [self scrollRectToVisible:pageViewLeftFrame animated:YES];
}

一切正常，除了我在页面上有一个带有按钮的子视图。如果用户触摸 subView 上的按钮，我希望能够忽略点击翻页，但我不知道该怎么做。

干杯

戴夫

Answer 1

最终对我来说效果最好的解决方案是使用 hitTest 来确定点击手势位置下方是否有任何按钮。如果有则忽略其余的手势代码。

似乎运作良好。想知道我所做的是否有任何问题。

- (void) tapGestureHandler:(UIGestureRecognizer *) gestureRecognizer {
    const CGFloat kTapMargin = 180;

    // Get the position of the point tapped in the window co-ordinate system
    CGPoint tapPoint = [gestureRecognizer locationInView:nil];

    // If there are no buttons beneath this tap then move to the next page if near the page edge
    UIView *viewAtBottomOfHeirachy = [self.window hitTest:tapPoint withEvent:nil];
    if (![viewAtBottomOfHeirachy isKindOfClass:[UIButton class]]) {

        // If the tap point is to the left of the page then go back a page
        if (tapPoint.x > (self.bounds.size.width - kTapMargin)) [self scrollRectToVisible:pageViewRightFrame animated:YES];

        // If the tap point is to the right of the page then go forward a page
        else if (tapPoint.x < kTapMargin) [self scrollRectToVisible:pageViewLeftFrame animated:YES];
    }   
}

Answer 2

Apple documentation 显示答案：

- (void)viewDidLoad {
      [super viewDidLoad];
      // Add the delegate to the tap gesture recognizer
      self.tapGestureRecognizer.delegate = self;
}

// Implement the UIGestureRecognizerDelegate method
-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:    (UITouch *)touch {
      // Determine if the touch is inside the custom subview
     if ([touch view] == self.customSubview){
         // If it is, prevent all of the delegate's gesture recognizers
         // from receiving the touch
        return NO;
     }
     return YES;
}

当然在这种情况下 customSubview 将是页面上的子视图，其中包含按钮（甚至是按钮）

Answer 3

斯威夫特 3

设置UITapGestureRecognizer

let tap = UITapGestureRecognizer(target: self, action: #selector(Class.didTap))
tap.delegate = self

UITapGestureRecognizer委托方法：

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
    return touch.view != buttonThatShouldCancelTapGesture
}

Answer 4

您可以继承 UIView 并覆盖 -touchesBegan 选择器，或者您可以使用子视图的 opaque 属性使它们对触摸“不可见”（如果 view.opaque = NO，视图将忽略触摸事件)。