註銷谷歌登錄並返回用戶登錄頁面：Swift/Xcode

Question

我已成功創建Google Sign In for my app，它工作正常，因此如果用戶登錄，用戶將被帶到一個標籤控制器。

現在，我已經簽出了標籤控制器中兩個項目上的按鈕，以便用戶能夠註銷。我想知道如何製作，以便用戶可以點擊退出按鈕，該按鈕會在應用中成功從Google註銷，然後將用戶返回到登錄頁面。

這裏是我的Main.storyboard的截圖：

MainStoryboard Screenshot

這裏是我的AppDelegate文件中的代碼：

AppDelegate.swift

import UIKit 
import Firebase 
import GoogleSignIn 

@UIApplicationMain 
class AppDelegate: UIResponder, UIApplicationDelegate, GIDSignInDelegate { 

    var window: UIWindow? 


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

     FIRApp.configure() 

     GIDSignIn.sharedInstance().clientID = FIRApp.defaultApp()?.options.clientID 
     GIDSignIn.sharedInstance().delegate = self 

     if GIDSignIn.sharedInstance().hasAuthInKeychain() { 
      print("User has been successfully signed in with Google") 
      let sb = UIStoryboard(name: "Main", bundle: nil) 
      if let tabBarVC = sb.instantiateViewController(withIdentifier: "TabController") as? UITabBarController { 
       window!.rootViewController = tabBarVC 
      } 
     } else { 
      print("User has failed in signing in with Google") 
      let sb = UIStoryboard(name: "Main", bundle: nil) 
      if let tabBarVC = sb.instantiateViewController(withIdentifier: "LogInViewController") as? ViewController { 
       window!.rootViewController = tabBarVC 
      } 
     } 

     return true 
    } 



    func sign(_ signIn: GIDSignIn!, didSignInFor user: GIDGoogleUser!, withError error: Error!) { 
     if let err = error { 
      print("Failed to log into Google: ", err) 
      return 
     } 

     print("Successfully logged into Google", user) 

     guard let idToken = user.authentication.idToken else { return } 
     guard let accessToken = user.authentication.accessToken else { return } 
     let credentials = FIRGoogleAuthProvider.credential(withIDToken: idToken, accessToken: accessToken) 

     FIRAuth.auth()?.signIn(with: credentials, completion: { (user, error) in 
      if let err = error { 
       print("Failed to create a Firebase User with Google account: ", err) 
       return 
      } 

      guard let uid = user?.uid else { return } 
      print("Successfully logged into Firebase with Google", uid) 
     }) 
    } 


    func application(_ app: UIApplication, open url: URL, options: [UIApplicationOpenURLOptionsKey : Any] = [:]) -> Bool { 



     GIDSignIn.sharedInstance().handle(url, 
              sourceApplication: options[UIApplicationOpenURLOptionsKey.sourceApplication] as! String!, 
              annotation: options[UIApplicationOpenURLOptionsKey.annotation]) 

     return true 
    } 

    func applicationWillResignActive(_ application: UIApplication) { 
     // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state. 
     // Use this method to pause ongoing tasks, disable timers, and invalidate graphics rendering callbacks. Games should use this method to pause the game. 
    } 

    func applicationDidEnterBackground(_ application: UIApplication) { 
     // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later. 
     // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits. 
    } 

    func applicationWillEnterForeground(_ application: UIApplication) { 
     // Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background. 
    } 

    func applicationDidBecomeActive(_ application: UIApplication) { 
     // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface. 
    } 

    func applicationWillTerminate(_ application: UIApplication) { 
     // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:. 
    } 


} 

而我˚F需要，ViewController.swift文件：

import UIKit 
import Firebase 
import GoogleSignIn 

class ViewController: UIViewController, GIDSignInUIDelegate { 

    override func viewDidLoad() { 
     super.viewDidLoad() 


     setupGoogleButtons() 
    } 

    fileprivate func setupGoogleButtons() { 
     //add google sign in button 
     let googleButton = GIDSignInButton() 
     googleButton.frame = CGRect(x: 16, y: 116 + 66, width: view.frame.width - 32, height: 50) 
     view.addSubview(googleButton) 
     //custom google button 
     let customButton = UIButton(type: .system) 
     customButton.frame = CGRect(x: 16, y: 116 + 66 + 66, width: view.frame.width - 32, height: 50) 
     customButton.backgroundColor = .orange 
     customButton.setTitle("Custom Google Sign In", for: .normal) 
     customButton.addTarget(self, action: #selector(handleCustomGoogleSign), for: .touchUpInside) 
     customButton.setTitleColor(.white, for: .normal) 
     customButton.titleLabel?.font = UIFont.boldSystemFont(ofSize: 14) 
     view.addSubview(customButton) 

     GIDSignIn.sharedInstance().uiDelegate = self 
    } 

    func handleCustomGoogleSign() { 
     GIDSignIn.sharedInstance().signIn() 
    } 

    override func didReceiveMemoryWarning() { 
     super.didReceiveMemoryWarning() 
     // Dispose of any resources that can be recreated. 
    } 


} 

Answer 1

這是很容易做到：

當你在action註銷，您只需設置window的rootvc到logint vc

window!.rootViewController = login vc