在不调用每个 viewDidAppear 的情况下解雇 rootViewController

Posted 2023-03-22

【中文标题】在不调用每个 viewDidAppear 的情况下解雇 rootViewController

【英文标题】：Dismissing to rootViewController without calling each viewDidAppear

【发布时间】：2019-11-20 18:16:34

【问题描述】：

我的视图控制器就像 MainView -> NavigationController A -> ViewController A -> ViewController B -> ViewController C，我想关闭 ViewControllers（A、B 和 C）并再次显示 MainView...我使用了这条线

 self.view.window?.rootViewController?.dismiss(animated: false, completion: nil)

它工作得很好..问题是在解除 viewControllers（A、B 和 C）时，它会调用每个 viewDidAppear，这会运行我不想运行的代码.. 解除并执行的最佳做法是什么返回MainView而不调用每个viewController

【问题讨论】：

@Sammy 1- 我不使用情节提要 2- 我将每个视图呈现为全屏视图 这是我转到 ViewController A 的代码 let vc = ViewControllerA() let navigationController = UINavigationController(rootViewController: vc) navigationController.modalPresentationStyle = .fullScreen senderVC.present(navigationController, animated: true, completion: nil)

【参考方案1】：

您必须有其他导致问题的代码。

这是一个完整的例子......

PresDisViewController 是起始视图控制器 它的按钮创建一个以ViewControllerA为根的导航控制器 ViewControllerA 有一个按下 ViewControllerB 的按钮 ViewControllerB 有一个按钮可以按下 ViewControllerC ViewControllerC 有一个按钮可以执行你的 self.view.window?.rootViewController?.dismiss(animated: false, completion: nil)

每个 VC 都实现 viewDidAppear() 并将自己打印到调试控制台。

运行时的输出：

viewDidAppear scratchy.PresDisViewController
viewDidAppear scratchy.ViewControllerA
viewDidAppear scratchy.ViewControllerB
viewDidAppear scratchy.ViewControllerC
viewDidAppear scratchy.PresDisViewController

如您所见，当导航控制器被解除时，viewDidAppear 不会在 VC 中调用。

import UIKit

class ViewControllerA: UIViewController 

    let btn: UIButton = 
        let v = UIButton()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.setTitle("Do Push", for: .normal)
        v.backgroundColor = .red
        return v
    ()

    override func viewDidLoad() 
        super.viewDidLoad()

        view.backgroundColor = .white

        view.addSubview(btn)

        NSLayoutConstraint.activate([
            btn.centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: -40.0),
            btn.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: 0.0),
        ])

        btn.addTarget(self, action: #selector(didTap(_:)), for: .touchUpInside)

    

    @objc func didTap(_ sender: Any?) -> Void 
        let vc = ViewControllerB()
        self.navigationController?.pushViewController(vc, animated: true)
    

    override func viewDidAppear(_ animated: Bool) 
        super.viewDidAppear(animated)
        print("viewDidAppear", NSStringFromClass(self.classForCoder))
    



class ViewControllerB: UIViewController 

    let btn: UIButton = 
        let v = UIButton()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.setTitle("Do Push", for: .normal)
        v.backgroundColor = .systemYellow
        return v
    ()

    override func viewDidLoad() 
        super.viewDidLoad()

        view.backgroundColor = .white

        view.addSubview(btn)

        NSLayoutConstraint.activate([
            btn.centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: 0.0),
            btn.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: 0.0),
        ])

        btn.addTarget(self, action: #selector(didTap(_:)), for: .touchUpInside)

    

    @objc func didTap(_ sender: Any?) -> Void 
        let vc = ViewControllerC()
        self.navigationController?.pushViewController(vc, animated: true)
    

    override func viewDidAppear(_ animated: Bool) 
        super.viewDidAppear(animated)
        print("viewDidAppear", NSStringFromClass(self.classForCoder))
    



class ViewControllerC: UIViewController 

    let btn: UIButton = 
        let v = UIButton()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.setTitle("Do Dismiss", for: .normal)
        v.backgroundColor = .blue
        return v
    ()

    override func viewDidLoad() 
        super.viewDidLoad()

        view.backgroundColor = .white

        view.addSubview(btn)

        NSLayoutConstraint.activate([
            btn.centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: 40.0),
            btn.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: 0.0),
        ])

        btn.addTarget(self, action: #selector(didTap(_:)), for: .touchUpInside)

    

    @objc func didTap(_ sender: Any?) -> Void 
        self.view.window?.rootViewController?.dismiss(animated: false, completion: nil)
    

    override func viewDidAppear(_ animated: Bool) 
        super.viewDidAppear(animated)
        print("viewDidAppear", NSStringFromClass(self.classForCoder))
    




class PresDisViewController: UIViewController 

    let btn: UIButton = 
        let v = UIButton()
        v.translatesAutoresizingMaskIntoConstraints = false
        v.setTitle("Do Present", for: .normal)
        v.backgroundColor = .orange
        return v
    ()

    override func viewDidLoad() 
        super.viewDidLoad()

        view.backgroundColor = .white

        view.addSubview(btn)

        NSLayoutConstraint.activate([
            btn.topAnchor.constraint(equalTo: view.topAnchor, constant: 60.0),
            btn.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: 0.0),
        ])

        btn.addTarget(self, action: #selector(didTap(_:)), for: .touchUpInside)

    

    @objc func didTap(_ sender: Any?) -> Void 
        let vcA = ViewControllerA()
        let navVC = UINavigationController(rootViewController: vcA)
        navVC.modalPresentationStyle = .fullScreen
        present(navVC, animated: true, completion: nil)
    

    override func viewDidAppear(_ animated: Bool) 
        super.viewDidAppear(animated)
        print("viewDidAppear", NSStringFromClass(self.classForCoder))
    

【参考方案2】：

这是通过 Storyboard 完成的。我不知道如何通过代码来做到这一点。我希望它有帮助 在你的 MainViewController 添加这个：

@IBAction func unwindToMainView(segue:UIStoryboardSegue)  

在所有其他ViewController（viewController A,ViewController B,ViewController C）中， 像这样单击并拖动

然后选择你在mainVC中添加的segue

现在选择那个segue并给它一个标识符

从这里你可以在任何你想要的地方使用该标识符执行 segue。我使用按钮来执行那个segue