Question

我在我的应用程序中实现了一个功能性教程介绍，但是当我最后一次滑动屏幕时，我似乎无法将页面视图弹出。我以为dismissViewControllerAnimated：completion：会工作

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
{
    NSUInteger index = ((PageContentViewController*) viewController).pageIndex;

    if (index == NSNotFound) {
        return nil;
    }

    index++;
    if (index == [self.pageTitles count]) {
        [self.pageViewController dismissViewControllerAnimated:YES completion:nil];
    }
    return [self viewControllerAtIndex:index];
}

我想出了如何让它消失，但当它到达最后一页时就会消失。我希望它显示最后一页，然后当用户再次在最后一页上滑动时离开。

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
{
    NSUInteger index = ((PageContentViewController*) viewController).pageIndex;

    if (index == NSNotFound) {
        return nil;
    }

    index++;
    if (index == [self.pageTitles count]) {
        [self.pageViewController.view removeFromSuperview];
    }
    return [self viewControllerAtIndex:index];
}

Answer 1

页面视图控制器是你的主要viewcontrollers子视图控制器，这是删除childViewController的正确方法：

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
{
    NSUInteger index = ((PageContentViewController*) viewController).pageIndex;

    if (index == NSNotFound) {
        return nil;
    }

    index++;

    if (index == [self.pageTitles count]) {
        [pageViewController willMoveToParentViewController:nil];  // 1
        [pageViewController.view removeFromSuperview];            // 2
        [pageViewController removeFromParentViewController];      // 3   
    }

    return [self viewControllerAtIndex:index];
}

Answer 2

同样遇到了同样的问题，我的解决方案是使用以下代码添加一个明确的额外页面：

ValueError: time data '2018-02-16T10:00:49ZParis, Madrid' does not match format '%Y-%m-%dT%H:%M:%SZ%z'

在

/// the index of the currently displayed page
fileprivate var currentIndex: Int = 0


func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {

    // didFinishAnimating gets called before viewControllerAfter, which means `currentIndex` will be 1 page behind, hence subtract 2 instead of 1
    if currentIndex == myViewControllers.count - 2 {
        //self.dismiss(animated: true, completion: nil)
        //.... dismiss pages here
    }
}

func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {

    guard let viewControllerIndex = myViewControllers.index(of: viewController) else { return nil }
    let previousIndex = viewControllerIndex - 1

    // track current page index
    currentIndex = Int(viewControllerIndex)

    // ..
}

func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {

    guard let viewControllerIndex = myViewControllers.index(of: viewController) else { return nil }

    let nextIndex = viewControllerIndex + 1

    // track page index
    currentIndex = Int(viewControllerIndex)

    // get next page
    if nextIndex < myViewControllers.count {
        return myViewControllers[nextIndex]
    }

    return nil
}

之前调用

didFinishAnimating。这意味着viewControllerAfter的值将在调用currentIndex时用于上一页。因此，为什么我减去2（而不是1）

获取页面视图以在最后一个屏幕上弹出

2 个答案: