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setViewControllers不起作用

[英]setViewControllers doesn't work

I'm trying to change the current ViewController of my UIPageViewController using a NEXT button. 我正在尝试使用NEXT按钮更改我的UIPageViewController的当前ViewController。 So I'm calling the function that's in my containterViewController in my mainViewController using a delegate. 所以我使用委托调用我的mainViewController中的containterViewController中的函数。 But it doesn't execute the setViewControllers line. 但它不执行setViewControllers行。

Here you can see my code: 在这里你可以看到我的代码:

This is the method that I call using my delegate: 这是我使用我的委托调用的方法:

func forwardPage() {
    print("Start")
    currentPage += 1
    print(vcs[currentPage])
    self.setViewControllers([vcs[currentPage]], direction: .forward, animated: true) { (true) in
        print("Done")
    }
}

Here's my delegate: 这是我的代表:

protocol WalkthroughViewControllerDelegate {
   func forwardPage()
   func currentIndex() -> Int
}

And here's the function that is connected to my NEXT button: 这是连接到我的NEXT按钮的功能:

@IBAction func nextButtonTapped(_ sender: Any) {
    if let index = delegate?.currentIndex() {
        print("Here... \(index)")
        switch index {
        case 0...1:
            print("Forwarding...")
            delegate?.forwardPage()
        case 2:
            dismiss(animated: true, completion: nil)
        default: break
        }
    }

    updateUI()
}

Everything but the "Done" gets printed 除了“完成”之外的所有内容都会被打印出来

I would really appreciate your help 我将衷心感谢您的帮助

I've been struggling because of this for quite some time now 我一直在努力,因为这已经有一段时间了

Thank you very much :) 非常感谢你 :)

EDIT: Maybe this happens because that UIPageViewController is inside a containerView. 编辑:也许这发生是因为UIPageViewController在containerView中。 But I'm not sure 但我不确定

SECOND EDIT: I've created a git-hub repository just for this issue. 第二次编辑:我已经为这个问题创建了一个git-hub存储库。 Here's the link: https://github.com/LennartPhil/App-Popup-Screen . 这是链接: https//github.com/LennartPhil/App-Popup-Screen I hope you can understand that I won't show you all of my files. 我希望你能理解我不会向你展示我的所有文件。

OK - the problem is that your code in viewDidLoad() : 好的 - 问题是你的代码在viewDidLoad()

    let storyboard = UIStoryboard(name: "ExtraViewControllers", bundle: nil)
    let walkthroughPageVC = storyboard.instantiateViewController(withIdentifier: "WalkthroughPageVC") as! WalkthroughPageViewController
    delegate = walkthroughPageVC

is creating a NEW instance of WalkthroughPageViewController , which goes out of scope as soon as viewDidLoad() exits. 正在创建一个WalkthroughPageViewController的新实例,一旦viewDidLoad()退出,它就会超出范围。 So it no longer exists. 所以它不再存在。

What you need to do instead is get a reference to it in prepare(for segue:...) , and set it as your delegate there: 您需要做的是在prepare(for segue:...)获取对它的引用prepare(for segue:...) ,并将其设置为您的委托:

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if let vc = segue.destination as? WalkthroughPageViewController {
        self.delegate = vc
    }
}

I forked your GitHub repo and added the files into a project, so you can see it run: https://github.com/DonMag/App-Popup-Screen 我分叉你的GitHub仓库并将文件添加到一个项目中,所以你可以看到它运行: https//github.com/DonMag/App-Popup-Screen

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