使用segue按下按钮后禁用PageViewController - Swift 4答案

【问题标题】：PageViewController Disabled after pressing button with segue - Swift 4使用segue按下按钮后禁用PageViewController - Swift 4
【发布时间】：2018-10-08 02:02:33
【问题描述】：

我成功实现了一个 PageViewController，我可以在其中滑动五个页面（ViewControllers）。问题是当我添加一个连接到其中一个 ViewController 的按钮时。它显示了页面，就像它应该的那样，但是我被困在那个页面上。 PageViewController 不再起作用。我不能再在页面之间滑动。

import UIKit

class PageViewController: UIPageViewController, UIPageViewControllerDataSource, UIPageViewControllerDelegate {

    lazy var subViewControllers:[UIViewController] = {
        return [
            UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewController1") as! ViewController1,
            UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewController2") as! ViewController2,
            UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewController3") as! ViewController3,
            UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewController4") as! ViewController4,
            UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewController5") as! ViewController5,
        ]
    }()

    override func viewDidLoad() {
    super.viewDidLoad()

        self.delegate = self
        self.dataSource = self

        setViewControllers([subViewControllers[0]], direction: .forward, animated: true, completion: nil)
    }

// MARK - UIPageViewControllerDataSource

    func presentationCount(for pageViewController: UIPageViewController) -> Int {
        return subViewControllers.count
    }

    func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
        let currentIndex:Int = subViewControllers.index(of: viewController) ?? 0
        if(currentIndex <= 0) {
            return nil
        }
        return subViewControllers[currentIndex-1]
    }

    func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
        let currentIndex:Int = subViewControllers.index(of: viewController) ?? 0
        if(currentIndex >= subViewControllers.count-1) {
            return nil
        }
        return subViewControllers[currentIndex+1]
   }
}

【问题讨论】：

不要将按钮与 segue 关联，而是将其与 IBAction 关联并在 IBAction 中调用 setViewControllers
我试过了，但我无法从按钮所在的 ViewController 访问 setViewControllers。上面的代码来自我的 PageViewController。该按钮位于 ViewController4 中，按下时显示 ViewController3。也许有一个我可以创建的功能。有什么代码可以推荐吗？

标签： ios swift4 segue uipageviewcontroller

【解决方案1】：

您可以将PageViewController 的引用传递给您的子视图控制器，以便您可以从子视图控制器调用PageViewController 的方法。例如，创建

var pageViewController : PageViewController?

在ViewController4 然后在subViewControllers 中赋值

lazy var subViewControllers:[UIViewController] = {
    let viewController4 = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewController4") as! ViewController4
    viewController4.pageViewController = self
    return [
        UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewController1") as! ViewController1,
        UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewController2") as! ViewController2,
        UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewController3") as! ViewController3,
        viewController4,
        UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewController5") as! ViewController5,
    ]
}()

然后您可以从ViewController4 调用PageViewController 的任何方法。为了简单起见，你可以在PageViewController中创建一个scrollToViewController3()方法

func scrollToViewController3()
{
    setViewControllers([subViewControllers[2]], direction: .reverse, animated: true, completion: nil)
}

并在ViewController4中致电pageViewController?.scrollToViewController3()

【讨论】：