ios - UIPageViewController 转换 'Unbalanced calls to begin/end appearance transitions for '

Question

当我浏览 UIPageViewController 时比它的过渡动画快我得到'Unbalanced calls to begin/end appearance transitions for <MyDataViewController> ' 直到我尝试翻页时，横向的两个 View 之一才会显示。

有人有解决这个错误的想法吗？

Answer 1

上面的答案是正确的，但我认为比需要的更详细，cookbook 很有帮助。所以这似乎对我有用:

在设置和调用pageViewController的view controller中， 声明:

@property (assign)              BOOL pageIsAnimating;

并在 viewDidLoad 中:

    pageIsAnimating = NO;

添加这个:

- (void)pageViewController:(UIPageViewController *)pageViewController willTransitionToViewControllers:(NSArray *)pendingViewControllers {
    pageIsAnimating = YES;
}

并添加几行到:

- (void)pageViewController:(UIPageViewController *)pageViewController
    didFinishAnimating:(BOOL)finished previousViewControllers:(NSArray *)previousViewControllers
   transitionCompleted:(BOOL)completed {
    if (completed || finished)   // Turn is either finished or aborted
        pageIsAnimating = NO;
    ...
}

通过拒绝提供 View Controller 信息来抑制手势:

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController
   viewControllerAfterViewController:(UIViewController *)viewController {
    if (pageIsAnimating)
        return nil;
    ...
    return after;
}

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController
  viewControllerBeforeViewController:(UIViewController *)viewController {
    if (pageIsAnimating)
        return nil;
    ...
    return before;
}

哦，方向更改会重置标志:

- (UIPageViewControllerSpineLocation)pageViewController:(UIPageViewController *)pageViewController
               spineLocationForInterfaceOrientation:(UIInterfaceOrientation)orientation {
    pageIsAnimating = NO;
    ...
}