ios - 如何在 Swift 中关闭当前的 ViewController 并更改为新的 ViewController？

Question

我是 iOS swift 的新手。我有三个 ViewController。页面 A 是根 Controller ，它将呈现给页面 B。它在页面 B 中有一个计时器。 5秒后，View会从page-B切换到page-C，同时关闭page-B。

在 ViewControll-B

class AViewController: UIViewController {

    var timer: Timer?

    override func viewDidLoad() {
        super.viewDidLoad()

        //set the timer , and chagne view to C ViewController
        Timer.scheduledTimer(timeInterval: 5,
                             target: self,
                             selector: #selector(self.changeToAnswerView),
                             userInfo: nil,
                             repeats: false)
    }


    @objc func changeToAnswerView() {
        dismissLoader()
    }

    func dismissLoader() {
        dismiss(animated: true) {
            print("Dismissing Loader view Controller")
        }
    }

    override func viewWillDisappear(_ animated: Bool) {
        //change view to Answer ViewController
        let filterVC = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "CViewControllerID")
        filterVC.modalPresentationStyle = UIModalPresentationStyle.custom
        self.present(filterVC, animated: true, completion: nil)
    }

}

计时器执行 5 秒后，BViewController 将关闭自身并呈现给 BViewController。

但是会出现如下错误:

whose view is not in the window hierarchy

我错过了什么吗？

问题:如何在 Swift 中关闭当前的 ViewController 并更改为新的 ViewController？

提前致谢。

Answer 1

这是您可以尝试的工作代码

您的 Controller 已被解雇并倾向于创建一个新的 Controller

import UIKit

class pdfVC: UIViewController
{

    var timer : Timer?

    override func viewDidLoad()
    {
        super.viewDidLoad()
        timer = Timer.scheduledTimer(timeInterval: 3, target: self, selector: #selector(pdfVC.timerAction), userInfo: nil, repeats: false)
    }

    @objc func timerAction()
    {
        if timer != nil {
            timer?.invalidate()
            dismiss(animated: true, completion: {
                print("Dismissed")
            })
        }
    }

    override func viewWillDisappear(_ animated: Bool) {
        if self.isBeingDismissed {
            let filterVC = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "demoViewController")
            filterVC.modalPresentationStyle = UIModalPresentationStyle.custom
            print("called")
            self.presentingViewController?.present(filterVC, animated: true, completion: nil)
        }
    }
}

输出