UIPageViewController取消了子UIView触及

Question

我有一个UIPageViewController，它包含几个UIViewControllers。每个UIViewController的视图都有一个子视图：MyUIView。我重写了touchesBegan和MyUIView中的所有其他3种方法。

当我在MyUIView中从上到下滑动时，我得到-touchesMoved：withEvent：调用没有问题，但是当我从左向右滑动时，UIPageViewController滚动，并且在MyUIView中调用了-touchesCancelled：withEvent：。 / p>

我没有在这4种方法中调用[super touchesXXX：withEvent：]，我认为这应该会阻止UIPageViewController接收触摸事件，但不知怎的，似乎UIPageViewController识别出滑动，并取消了MyUIView触摸。

我注意到另一个细节，如果我触摸MyUIView并从左向右移动到非常慢的距离，我仍然得到-touchesMoved：withEvent：called。但是在一定距离（可能是10分）之后，UIPageViewController似乎识别出滑动和滚动，同时取消了MyUIView中的触摸。

问题是，发生了什么？如何在MyUIView中使用触摸事件，并停止向上游转发事件？

Answer 1

使用Xcode＆＃34;调试视图层次结构＆＃34;功能，我找到了UIPageViewController.view的视图层次结构：

_UIQueuingScrollView看起来很可疑，所以我记录了它的手势识别器：

2016-10-26 19:02:16.846 LSYReader[5202:293575] _UIQueuingScrollView gesture:<UIScrollViewDelayedTouchesBeganGestureRecognizer: 0x6080001b4f20; state = Possible; delaysTouchesBegan = YES; view = <_UIQueuingScrollView 0x7f884003ba00>; target= <(action=delayed:, target=<_UIQueuingScrollView 0x7f884003ba00>)>>
2016-10-26 19:02:16.848 LSYReader[5202:293575] _UIQueuingScrollView gesture:<UIScrollViewPanGestureRecognizer: 0x7f883e70a240; state = Possible; delaysTouchesEnded = NO; view = <_UIQueuingScrollView 0x7f884003ba00>; target= <(action=handlePan:, target=<_UIQueuingScrollView 0x7f884003ba00>)>; must-fail = {
    <UIScrollViewPagingSwipeGestureRecognizer: 0x6080001dc5c0; state = Possible; view = <_UIQueuingScrollView 0x7f884003ba00>; target= <(action=_handleSwipe:, target=<_UIQueuingScrollView 0x7f884003ba00>)>>
}>
2016-10-26 19:02:16.849 LSYReader[5202:293575] _UIQueuingScrollView gesture:<UIScrollViewPagingSwipeGestureRecognizer: 0x6080001dc5c0; state = Possible; view = <_UIQueuingScrollView 0x7f884003ba00>; target= <(action=_handleSwipe:, target=<_UIQueuingScrollView 0x7f884003ba00>)>; must-fail-for = {
    <UIScrollViewPanGestureRecognizer: 0x7f883e70a240; state = Possible; enabled = NO; delaysTouchesEnded = NO; view = <_UIQueuingScrollView 0x7f884003ba00>; target= <(action=handlePan:, target=<_UIQueuingScrollView 0x7f884003ba00>)>>
}>

然后，我禁用了这些手势识别器，现在MyUIView中的一切正常。

[_pageViewController.view.subviews enumerateObjectsUsingBlock:^(__kindof UIView * _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {

    if ([obj isKindOfClass:NSClassFromString(@"_UIQueuingScrollView")]) {
        [obj.gestureRecognizers enumerateObjectsUsingBlock:^(__kindof UIGestureRecognizer * _Nonnull obj1, NSUInteger idx1, BOOL * _Nonnull stop1) {
            if ([obj1 isKindOfClass:NSClassFromString(@"UIScrollViewDelayedTouchesBeganGestureRecognizer")]) {
                obj1.enabled = NO;
            } else if ([obj1 isKindOfClass:NSClassFromString(@"UIScrollViewPanGestureRecognizer")]) {
                obj1.enabled = NO;
            } else if ([obj1 isKindOfClass:NSClassFromString(@"UIScrollViewPagingSwipeGestureRecognizer")]) {
                obj1.enabled = NO;
            }
        }];
    }
}];