带有垂直平移手势的水平滚动 UIScrollView

Question

我正在尝试实现一个 UIScrollView，其中水平平移滚动滚动视图中的图片，但垂直平移执行我拥有的另一个操作。现在我有一个 UIScrollView，它在禁用垂直滚动的情况下进行分页，它可以很好地滚动浏览图片，但是我疯狂地试图找到一种方法来拦截垂直平底锅并调用我自己的方法而不是垂直平底锅被吃掉滚动视图。我能够做到

    UIPanGestureRecognizer *panUp = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePanGesture:)];
[self.scrollView addGestureRecognizer:panUp];
[scrollView.panGestureRecognizer setEnabled:NO];

这让我可以完全控制我的 handlePanGesture: 方法中的平移，但这并不是特别有用，因为我觉得我基本上要重写我试图避免的所有滚动逻辑。任何有关如何实现这一目标的帮助或指导将不胜感激。

谢谢！

Answer 1

从 iOS 5 开始，UIScrollViewexposes its UIPanGestureRecognizer。将自定义滑动的delegate 设置为self 并将gestureRecognizer 设置为属性或ivar，并使您的类符合<UIGestureRecognizerDelegate> 协议。然后，像这样实现UIGestureRecognizerDelegate的– gestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer:：

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
    if ([gestureRecognizer isEqual:self.swipe] && [otherGestureRecognizer isEqual:self.scrollView.panGestureRecognizer])
    {
         return NO;
    }
    return YES; // the default for this method
}

Answer 2

我添加了 UIPanGestureRecognizer 然后 setupgestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer: 像这样：

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
    if ([gestureRecognizer isEqual:self.panGesture] && [otherGestureRecognizer isEqual:self.collectionView.panGestureRecognizer]){
        return YES;
    }
    return NO;
}

我还添加了签到gestureRecognizerShouldBegin:

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer {
    if ([gestureRecognizer isEqual:self.panGesture]) {
        if (gestureRecognizer.numberOfTouches > 0) {
            CGPoint point = [gestureRecognizer locationOfTouch:0 inView:gestureRecognizer.view];
            CGFloat distX = abs(self.collectionView.lastTouchPos.x - point.x);
            CGFloat distY = abs(self.collectionView.lastTouchPos.y - point.y);
            if (distX > distY) {
                return NO;
            }
        } else {
            return NO;
        }
    }
    return YES;
}

仅在向上或向下平移时使用self.panGesture。

更新

https://stackoverflow.com/a/8603839/667834 似乎对gestureRecognizerShouldBegin 有更好的方法

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer {
    if ([gestureRecognizer isEqual:self.panGesture]) {
        if (gestureRecognizer.numberOfTouches > 0) {
            CGPoint translation = [self.panGesture velocityInView:self.collectionView];
            return fabs(translation.y) > fabs(translation.x);
        } else {
            return NO;
        }
    }
    return YES;
}

Answer 3

如果您想使用平移手势，我认为这会很困难，因为滚动视图使用了这些手势。但是，如果您可以使用滑动，则很容易实现。

    UISwipeGestureRecognizer *swipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handlePanGesture:)];
    swipe.direction = UISwipeGestureRecognizerDirectionDown | UISwipeGestureRecognizerDirectionUp;
    [self.scrollView addGestureRecognizer:swipe];

我对此进行了测试，调用处理程序可以正常工作，并且您不需要禁用滚动视图的平移手势识别器（在我的测试中，滚动视图足够高并且内容足够短以至于没有垂直滚动——我不知道这是否必要）。