ios - 如何将 UITabBarController 导航到 ViewController？

Question

我在里面有一个 TabBarController 我正在加载两个 ViewControllers。

import UIKit

class TabBarViewController: UITabBarController {

    override func viewDidLoad() {
        super.viewDidLoad()

    }
}

图片:

class AttendanceViewController: UIViewController,UIApplicationDelegate,
    UICollectionViewDelegateFlowLayout,UINavigationControllerDelegate,
    CLLocationManagerDelegate,UIImagePickerControllerDelegate {

    override func viewWillAppear(_ animated: Bool) {
    if  Auth.auth().currentUser?.uid == nil {
        //Below code is not working
        let vc = UIStoryboard.init(name: "Main", bundle: Bundle.main)
        .instantiateViewController(withIdentifier: "LoginViewController") as? LoginViewController
        self.navigationController?.pushViewController(vc!, animated: true)
        print("user is not login in redirect to login page")
        return
    }else{
        print("User Successfully loginedin")
    }
}

}

Note : I have two view controller like AttendanceViewController and TaskViewController I want to check if user is not login then I want to redirect to my LoginViewController I tried above code it's was not working

Answer 1

嘿，我刚刚创建了一个示例，它将帮助您:-

我只是使用 userdefaults 来保存 loginState

这里是:-

1).任务 View Controller

我刚刚在其中创建了一个注销按钮

import UIKit

class TaskViewController: UIViewController {


@IBOutlet weak var signOutButton: UIButton!

override func viewDidLoad() {
    super.viewDidLoad()

    // Do any additional setup after loading the view.
}

override func viewDidLayoutSubviews() {
    signOutButton.layer.cornerRadius = signOutButton.layer.frame.height/2
}



@IBAction func signOutButtonTapped(_ sender: Any) {

    UserDefaults.standard.set(false, forKey: "isUserLoggedIn")  // here I remove the boolean value
    UserDefaults.standard.synchronize()
    let storyBoard = UIStoryboard(name: "Login", bundle: nil)
    let loginVc = storyBoard.instantiateViewController(withIdentifier: "LoginViewController") as! LoginViewController
    let rootVc = UINavigationController(rootViewController: loginVc)
    UIApplication.shared.keyWindow?.rootViewController = rootVc

}



}

2). AttendanceViewController - 我没有在里面创建任何东西

import UIKit

class AttendanceViewController: UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()

    // Do any additional setup after loading the view.
}


}

这两个 Controller 都在 TabBarController 里面，它是 HomeController

import UIKit

class HomeController: UITabBarController {

override func viewDidLoad() {
    super.viewDidLoad()


}

}

我在 Main.storyboard 文件中创建了它:-

并在 login.storyboard 文件中创建了 LoginViewController

LoginViewController:- 这里保存了 loginState

import UIKit

class LoginViewController: UIViewController {

@IBOutlet weak var loginButton: UIButton!


override func viewDidLoad() {
    super.viewDidLoad()

    // Do any additional setup after loading the view.
}

override func viewDidLayoutSubviews() {
    loginButton.layer.cornerRadius = loginButton.layer.frame.height/2
}


@IBAction func loginButtonTapped(_ sender: Any) {

    let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
    let viewController = mainStoryboard.instantiateViewController(withIdentifier: "HomeController") as! HomeController
    UserDefaults.standard.set(true, forKey: "isUserLoggedIn")
    UserDefaults.standard.synchronize()
    UIApplication.shared.keyWindow?.rootViewController = viewController

}

}

最后在 Appdelegate.swift 中检查 didFinishLaunchingWithOptions 中的登录状态，如下所示:-

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

    let userLoginStatus = UserDefaults.standard.bool(forKey: "isUserLoggedIn")
    print(userLoginStatus)

    if(userLoginStatus)
    {
        let mainStoryBoard = UIStoryboard(name: "Main", bundle: nil)
        let centerVC = mainStoryBoard.instantiateViewController(withIdentifier: "HomeController") as! HomeController
        window!.rootViewController = centerVC
        window!.makeKeyAndVisible()
    } else {

        let mainStoryBoard = UIStoryboard(name: "Login", bundle: nil)
        let centerVC = mainStoryBoard.instantiateViewController(withIdentifier: "LoginViewController") as! LoginViewController
        window!.rootViewController = centerVC
        window!.makeKeyAndVisible()
    }

    return true
}

这是完整的项目 - https://www.dropbox.com/s/3d34raovyx6orda/saveLogin.zip?dl=0