UIPageControl 未正确更新为 UIPageViewController 中当前页面的索引

Question

我有一个 UIPageViewController，它以编程方式内置了一个 PageControl。我有一个数组，用于跟踪可以分页的视图控制器，我正在尝试让 PageControl 显示与当前相关的点查看控制器页面。

我有以下用于向后和向前分页的代码：

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

    guard let vcIndex = viewControllerList.index(of: viewController) else {
        return nil
    }

    let previousIndex = vcIndex - 1

    guard previousIndex >= 0 else {return nil}

    guard viewControllerList.count > previousIndex else {return nil}


    self.pageControl.currentPage = previousIndex

    return viewControllerList[previousIndex]

}

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

    guard let vcIndex = viewControllerList.index(of: viewController) else {return nil}

    let nextIndex = vcIndex + 1



    guard viewControllerList.count != nextIndex else {return nil}

    guard viewControllerList.count > nextIndex else {return nil}


    self.pageControl.currentPage = nextIndex

    return viewControllerList[nextIndex]

}

当我将 PageControl 的当前页面设置为 nextIndex 或 previousIndex 时，我相信它应该为正在显示的当前视图控制器的页面显示正确的点，但是它经常错过中间索引（有三个点总数）。它通常只是在第 1 个和第 3 个点之间来回移动，并且不准确。

如果有更好的方法，我也会接受其他答案。

Answer 1

是因为你把pageControl的当前索引设置错了。您必须将其设置为：

func pageViewController(UIPageViewController, willTransitionTo: [UIViewController]) Called before a gesture-driven transition begins. 或

func pageViewController(UIPageViewController, didFinishAnimating: Bool, previousViewControllers: [UIViewController], transitionCompleted: Bool) Called after a gesture-driven transition completes. 这两种方法都来自 UIPageViewControllerDelegate

UIPageControl 未正确更新为 UIPageViewController 中当前页面的索引

UIPageControl not correctly updating to index of current page in UIPageViewController

arrays

swift

uipageviewcontroller

indexof

uipagecontrol