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检测UIPageViewController的当前页面

uipageviewcontroller swift3 ios

Elia Crocetta · 技术社区 · 8 年前

下面是我的委托方法和ViewController数组:

lazy var VCArr: [UIViewController] = {
    let firstVC = self.storyboard!.instantiateViewController(withIdentifier: "FirstTutorialPage")
    let secondVC = self.storyboard!.instantiateViewController(withIdentifier: "SecondTutorialPage")
    let thirdVC = self.storyboard!.instantiateViewController(withIdentifier: "ThirdTutorialPage")
    let fourthVC = self.storyboard!.instantiateViewController(withIdentifier: "FourthTutorialPage")
    return [firstVC, secondVC, thirdVC, fourthVC]
}()

委托方法

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

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

    let previousIndex = viewControllerIndex - 1

    guard previousIndex >= 0 else {
        return nil
    }

    guard self.VCArr.count > previousIndex else {
        return nil
    }

    return self.VCArr[previousIndex]
}

func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
    guard let viewControllerIndex = self.VCArr.index(of: viewController) else {
        return nil
    }

    let nextIndex = viewControllerIndex + 1

    guard nextIndex < self.VCArr.count else {
        return nil
    }

    guard self.VCArr.count > nextIndex else {
        return nil
    }

    return self.VCArr[nextIndex]
}

谢谢大家。

5 回复 | 直到 8 年前

Francesco 8 年前

我的解决方案在于实现该功能 pageViewController(_:didFinishAnimating:previousViewControllers:transitionCompleted:) 的 UIPageViewControllerDelegate

if completed {
    if let currentViewController = pageViewController.viewControllers?.first,
    let index = pages.index(of: currentViewController) {
        currentIndex = index
    }
}

哪里 pages 是我的页面视图控制器的属性,我在其中存储要显示的所有视图控制器,并且 currentIndex 是一个属性,用于跟踪当前页面的索引(也称为视图控制器),以便在代码的其他部分中使用它。

Sergey Bystrov 8 年前

尝试获取第一个视图控制器

    if let vc = pageViewController.viewControllers?[0] {
        ... vc is current controller...
    }

func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
    if let vc = pageViewController.viewControllers?[0] {
        ... vc is current controller...
    }
}

nao 8 年前

尝试此委托方法。

var currentIndex = 0

func pageViewController(_ pageViewController: UIPageViewController, willTransitionTo pendingViewControllers: [UIViewController]) {
    guard let nextViewController = pendingViewControllers[0] as? ViewController else { return }
    self.currentIndex = nextViewController.index
}

Francojamesfan 7 年前

像这样设置didFinishAnimating pageViewController数据源函数。存储数据源的属性。在这种情况下,我将其命名为 orderedViewControllers 。然后当您滑动时,当前索引将打印到控制台。

func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
    let pageContentViewController = pageViewController.viewControllers![0]
    let index = orderedViewControllers.index(of: pageContentViewController)!
    print(index)
}

-1

Szu 8 年前

在这里,您可以使用 % 操作人员

let nextIndex = (viewControllerIndex + 1) % VCArr.count
let previousIndex = (VCArr.count + viewControllerIndex - 1) % VCArr.count