UIPageViewController有时会在没有动画的情况下转换。为什么？

我有一个使用UIPageViewController浏览它的内容一本书的应用程序。出于某种原因，有时我翻动页面（用滑动手势），并发生转换，但没有动画。没有翻页动画，但新的内容就在那里。UIPageViewController有时会在没有动画的情况下转换。为什么？

这是为什么？难道是因为我在后台发生了一些数据库调用，可能会破坏UI动画？

感谢

编辑：这里是处理过渡

#pragma mark - UIPageViewControllerDataSource Methods 

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController 
    viewControllerBeforeViewController:(UIViewController *)viewController 
{ 
currentIndex = [self.modelArray indexOfObject:[(ContentViewController *)viewController labelContents]]; 
if(currentIndex == 0) 
{ 
    return nil; 
} 
ContentViewController *contentViewController = [[ContentViewController alloc] init]; 
contentViewController.labelContents = [self.modelArray objectAtIndex:currentIndex - 1]; 

[data setCurrentPage:currentIndex-1]; 
return contentViewController; 
} 

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController 
    viewControllerAfterViewController:(UIViewController *)viewController 
{ 
currentIndex = [self.modelArray indexOfObject:[(ContentViewController *)viewController labelContents]]; 
if(currentIndex == self.modelArray.count-1) 
{ 
    return nil; 
} 
ContentViewController *contentViewController = [[ContentViewController alloc] init]; 
contentViewController.labelContents = [self.modelArray objectAtIndex:currentIndex + 1]; 

[data setCurrentPage:currentIndex+1]; 


return contentViewController; 
} 

#pragma mark - UIPageViewControllerDelegate Methods 

- (UIPageViewControllerSpineLocation)pageViewController:(UIPageViewController *)pageViewController 
       spineLocationForInterfaceOrientation:(UIInterfaceOrientation)orientation 
{ 
if(UIInterfaceOrientationIsPortrait(orientation)) 
{ 
    //Set the array with only 1 view controller 
    UIViewController *currentViewController = [self.pageViewController.viewControllers objectAtIndex:0]; 
    NSArray *viewControllers = [NSArray arrayWithObject:currentViewController]; 
    [self.pageViewController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:YES completion:NULL]; 

    //Important- Set the doubleSided property to NO. 
    self.pageViewController.doubleSided = NO; 
    //Return the spine location 
    return UIPageViewControllerSpineLocationMin; 
} 
else 
{ 
    NSArray *viewControllers = nil; 
    ContentViewController *currentViewController = [self.pageViewController.viewControllers objectAtIndex:0]; 

    currentIndex = [self.modelArray indexOfObject:[(ContentViewController *)currentViewController labelContents]]; 
    if(currentIndex == 0 || currentIndex %2 == 0) 
    { 
     UIViewController *nextViewController = [self pageViewController:self.pageViewController viewControllerAfterViewController:currentViewController]; 
     viewControllers = [NSArray arrayWithObjects:currentViewController, nextViewController, nil]; 
    } 
    else 
    { 
     UIViewController *previousViewController = [self pageViewController:self.pageViewController viewControllerBeforeViewController:currentViewController]; 
     viewControllers = [NSArray arrayWithObjects:previousViewController, currentViewController, nil]; 
    } 
    //Now, set the viewControllers property of UIPageViewController 
    [self.pageViewController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:YES completion:NULL]; 

    return UIPageViewControllerSpineLocationMid; 
} 
}

来源

2012-02-08 Lizza

它可能是一个漏洞，你可以发布您的代码 – iProRage 2012-02-08 01:25:58

，我面临同样的问题。你解决了吗？提前致谢 – Soniya 2012-03-05 10:47:42

我想这是因为你行的代码：

[data setCurrentPage:currentIndex-1];

在 viewControllerBeforeViewController:和 viewControllerAfterViewController:功能

。

这些功能只需要返回一个适当的viewController。变化的电流控制器和播放动画的工作是不是你的，但UIPageViewControllerDataSource委托。如果你自己设置它，也不会有动画

来源

2012-06-05 04:10:02

UIPageViewController有时会在没有动画的情况下转换。为什么？

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