在同一个标签栏项目上加载新的 viewController 无效

Question

所以我在同一个标签栏项目上加载新的视图控制器时遇到了问题。我有一个标签栏控制器作为我的根控制器，标签栏上有 4 个标签。其中之一是帐户选项卡，当用户登录时，他需要查看其帐户详细信息的概览，但是当没有用户时，该选项卡栏项目上需要有一个登录/登录页面。目前，我的 tabbarcontroller 有一个自定义选项卡栏 class，它具有我认为是解决方案但没有任何反应的功能。我在需要加载的视图控制器（用户详细信息页面）中放置了一个断点，它出现在 ViewDidLoad 中，因此它加载但没有出现在屏幕上。

希望我能最终解决这个问题！

亲切的问候 B.

这是我的自定义标签栏控制器class:

import UIKit

class TabBarViewController: UITabBarController, UITabBarControllerDelegate {
    var window: UIWindow?
    override func viewDidLoad() {
        super.viewDidLoad()
        self.delegate = self

    }


    func tabBarController(_ tabBarController: UITabBarController,
                          shouldSelect viewController: UIViewController) -> Bool{
        let frame = UIScreen.main.bounds
        window = UIWindow(frame: frame)
        let index = tabBarController.viewControllers?.firstIndex(of: viewController)
        if index == 3{ // Index of Account tab
            let mainStoryBoard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
            let loginVC = mainStoryBoard.instantiateViewController(withIdentifier: "MessagesViewController") as! MessagesViewController
            window?.rootViewController = loginVC
            window?.makeKeyAndVisible()
        }
        return true// you decide
    }
}

Answer 1

更改 rootViewController 在 Swift 中是不好的做法。

处理此类任务的正确方法是覆盖您的 accountViewController 的 viewWillAppear 函数以确定用户是否未登录并显示您的 loginViewController。尝试类似的东西：

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    // authManager would be a custom class that manages authorization with a property for loggedIn
    if authManager.loggedIn == false {
        guard let loginVC = UIStoryboard.init(name: "Main", bundle: Bundle.main).instantiateViewController(withIdentifier: "login") as? LoginViewController else { return }
        self.present(loginVC, animated: true, completion: nil)
    }
}

Answer 2

这里是呈现全屏登录Vc的代码

func tabBarController(_ tabBarController: UITabBarController,
                          shouldSelect viewController: UIViewController) -> Bool{
        let frame = UIScreen.main.bounds
        window = UIWindow(frame: frame)
        let index = tabBarController.viewControllers?.firstIndex(of: viewController)
        if index == 1{ // Index of Account tab
            let mainStoryBoard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
            let loginVC = mainStoryBoard.instantiateViewController(withIdentifier: "MessagesViewController") as! MessagesViewController
            loginVC.modalPresentationStyle = .fullScreen
            self.present(loginVC, animated: false, completion: nil)
        }
        return true// you decide
    }

如果您还想要底栏...您的 viewController 应该是导航控制器，您可以按您想要的 ViewController 然后点赞

func tabBarController(_ tabBarController: UITabBarController,
                          shouldSelect viewController: UIViewController) -> Bool{
        let frame = UIScreen.main.bounds
        window = UIWindow(frame: frame)
        let index = tabBarController.viewControllers?.firstIndex(of: viewController)
        if index == 1{ // Index of Account tab
            let mainStoryBoard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
            let loginVC = mainStoryBoard.instantiateViewController(withIdentifier: "MessagesViewController") as! MessagesViewController
           // loginVC.modalPresentationStyle = .fullScreen

            if let navigation = viewController as? UINavigationController {

                navigation.pushViewController(loginVC, animated: false)
            }
        }
        return true// you decide
    }

它将在顶部显示后退按钮和导航栏如果你不想要 NavigationBar 那么在你的 MessagesViewController 中加载函数调用

override func viewDidLoad() {
        super.viewDidLoad()
        self.navigationController?.isNavigationBarHidden = true
        // Do any additional setup after loading the view.
    }

如果你只想隐藏后退按钮，请调用

override func viewDidLoad() {
        super.viewDidLoad()
        self.navigationItem.setHidesBackButton(true, animated: false);
        // Do any additional setup after loading the view.
    }

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