pageViewController setViewControllers 因“无效参数不满足:[views count] == 3"而崩溃； [英] pageViewController setViewControllers crashes with "Invalid parameter not satisfying: [views count] == 3"

问题描述

我知道还有其他几个类似的问题，但我找不到解决我的问题的方法.我使用一个 pageViewController 来显示不同的 ViewControllers.每次 pageViewController 向前移动时，我都会检查 lastPage 的输入.如果它是错误的 pageViewController 应该使用 setViewController 方法返回到该页面.如果没有此方法，一切正常，但如果我尝试使用它，应用程序将崩溃，但出现以下异常:

I know that there are several other questions like this, but i couldn't find a solution for my problem. I use a pageViewController which displays different ViewControllers. Every time the pageViewController moves forward I check the input of the lastPage. If it's wrong the pageViewController should go back to that page by using the setViewController method. Without this method everything works fine but if I try to use it the app crashes with the following exception:

19:48:25.596 Phook[23579:60b] *** Assertion failure in -[_UIQueuingScrollView _replaceViews:updatingContents:adjustContentInsets:animated:], /SourceCache/UIKit_Sim/UIKit-2935.137/_UIQueuingScrollView.m:383  
2014-06-02 19:48:25.600 Phook[23579:60b] *** Terminating app due to uncaught   exception 'NSInternalInconsistencyException', reason: 'Invalid parameter not satisfying:   [views count] == 3'

这是我的代码:

- (void)pageViewController:(UIPageViewController *)pageViewController didFinishAnimating:(BOOL)finished
   previousViewControllers:(NSArray *)previousViewControllers transitionCompleted:(BOOL)completed
{
    if (completed && finished)
    {

        RegisterUserPageContent* lastPage = (RegisterUserPageContent*)previousViewControllers[ previousViewControllers.count-1];
        int lastIndex   = lastPage.pageIndex;
        int newIndex    = ((RegisterUserPageContent*)[self.pageViewController.viewControllers objectAtIndex:0]).pageIndex;

        if (newIndex > lastIndex)
        {   // Moved Forward
            if(!lastPage.testInput)
            {
                [self.pageViewController setViewControllers:@[ [self.storyboard instantiateViewControllerWithIdentifier:_pageStoryBoardIDs[0]] ]
                                         direction:UIPageViewControllerNavigationDirectionReverse
                                         animated:YES completion:nil];


            }
        }
        else
        {   // Moved Reverse

        }
    }
}

正如我已经说过的.我搜索了很多并实施了一些解决方案，但没有任何帮助.谢谢.

As I already said. I searched a lot and implemented some solutions but nothing helped. Thanks.

推荐答案

我遇到了同样的问题，并且能够使用这个答案中的提示解决它https://stackoverflow.com/a/20973822/3757370.只需将 setViewControllers:direction:animated:completion: 代码放在主队列上的 dispatch_async 块中即可为我修复它.对你来说，这看起来像

I ran into the same problem, and was able to solve it using a tip from this answer https://stackoverflow.com/a/20973822/3757370. Simply placing the setViewControllers:direction:animated:completion: code inside of a dispatch_async block on the main queue fixed it for me. For you this would look like

dispatch_async(dispatch_get_main_queue(), ^{
    [self.pageViewController setViewControllers:@[ [self.storyboard instantiateViewControllerWithIdentifier:_pageStoryBoardIDs[0]] ]
                                     direction:UIPageViewControllerNavigationDirectionReverse
                                     animated:YES completion:nil];
});

希望有帮助！

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