在 Xcode 11.5 中從 AppDelegate 訪問 ViewController（firebase google 登錄）

Question

我正在為玩具應用程序實施 Firebase Google 登錄。 Google 登錄后，應用程序假設從 SignInViewController 移動到 HomePageViewController。 根據 firebase 指令（ https://firebase.google.com/docs/auth/ios/google-signin ），1. GDSignInButton 安裝在 SignInViewController 2. AppDelegate 應該實現 GDSignInDelegate 的 sign()。

在 AppDelegate 中的 sign() 結束之前，我應該如何告訴 SignInViewController，你可以移動到 HomePageViewController。 我已成功按照說明完成登錄。但我不知道如何在 AppDelegate 中轉換視圖控制器。

請注意，在 Xcode 11.5 中，有一個 SceneDelegate，它擁有一個 window，該 window 在舊版本中曾經屬於 AppDelegate。 所以我們無法在 AppDelegate 中獲得對包含視圖控制器的 Window 的引用。 提前致謝！

我的問題解決了。 感謝那些提供幫助的人：但我的問題仍然存在，想象一下你在 AppDelegate 中？ 您如何與（訪問）您的觀點進行交流？

Answer 1

這是我在 iOS 13 中執行此操作的代碼：

AppDelegate.swift

import Firebase
import GoogleSignIn

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    // configure de firebase app
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        FirebaseApp.configure()
        return true
    }

    // other methods in app delegate

    @available(iOS 9.0, *)
    func application(_ application: UIApplication, open url: URL, options: [UIApplication.OpenURLOptionsKey : Any]) -> Bool {
        return GIDSignIn.sharedInstance().handle(url)
    }
}

SceneDelegate.swift

import Firebase
import GoogleSignIn
import FirebaseAuth

// conform to the google sign in delegate
class SceneDelegate: UIResponder, UIWindowSceneDelegate, GIDSignInDelegate {

    var window: UIWindow?

    // when the app launches, it checks if the user is signed in, and redirect to the correct view controller
    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
        let storyboard =  UIStoryboard(name: "Main", bundle: nil)
        if let windowScene = scene as? UIWindowScene {
            self.window = UIWindow(windowScene: windowScene)
            if Auth.auth().currentUser != nil {
                // redirect to the home controller
                self.window!.rootViewController = storyboard.instantiateViewController(withIdentifier: "HomeTabBarController")
                self.window!.makeKeyAndVisible()
            } else {
                // redirect to the login controller
                self.window!.rootViewController = storyboard.instantiateViewController(withIdentifier: "LoginViewController")
                self.window!.makeKeyAndVisible()
            }
        }
        GIDSignIn.sharedInstance().clientID = FirebaseApp.app()?.options.clientID
        GIDSignIn.sharedInstance().delegate = self
    }

    // handle the sign in to redirect to the home controller
    func sign(_ signIn: GIDSignIn!, didSignInFor user: GIDGoogleUser!, withError error: Error?) {
        if error != nil {
            return
        }

        guard let authentication = user.authentication else { return }
        let credential = GoogleAuthProvider.credential(withIDToken: authentication.idToken, accessToken: authentication.accessToken)
        Auth.auth().signIn(with: credential) { (authResult, error) in
            if let error = error {
                print(error.localizedDescription)
                return
            }
            let storyboard =  UIStoryboard(name: "Main", bundle: nil)
            // redirect the user to the home controller
            self.window!.rootViewController = storyboard.instantiateViewController(withIdentifier: "HomeTabBarController")
            self.window!.makeKeyAndVisible()
        }
    }

    func sign(_ signIn: GIDSignIn!, didDisconnectWith user: GIDGoogleUser!, withError error: Error!) {
        // Perform any operations when the user disconnects from app here.
        // ...

    }


}

Answer 2

如果您的項目使用SceneDelegate ，那么您必須使用以下代碼來獲取密鑰 window。 從keyWindow您可以使用 .rootViewController 訪問.rootViewController並將其向下轉換為MyViewController並相應地訪問它。

let keyWindow = UIApplication.shared.connectedScenes
        .filter({$0.activationState == .foregroundActive})
        .map({$0 as? UIWindowScene})
        .compactMap({$0})
        .first?.windows
        .filter({$0.isKeyWindow}).first
let myViewContorller = keyWindow?.rootViewController as? MyViewController

Answer 3

在 appDelegate 中：-

可以通過將其作為 RootViewController 傳遞

func application(application: UIApplication, didFinishLaunchingWithOptions
launchOptions: [NSObject: AnyObject]?) -> Bool {
    self.window = UIWindow(frame: UIScreen.main.bounds)
     let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
     let viewController : UIViewController = storyBoard.instantiateViewControllerWithIdentifier(“InitialControllerID”) as InitialViewController
     self.window?.rootViewController = viewController
     self.window?.makeKeyAndVisible()

     return true
}

或者，如果 rootViewController 是 UINavigation Controller 類型，那么將您的主屏幕推到它上面：-

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
let rootViewController = self.window!.rootViewController as! UINavigationController
let mainStoryboard = UIStoryboard(name: "Main", bundle: nil)
let viewController = mainStoryboard.instantiateViewController(withIdentifier: “InitialControllerID") as! InitialViewController
rootViewController.pushViewController(viewController, animated: true)
return true
}

或者

在這篇文章的基礎上：- “ https://www.dev2qa.com/how-to-set-application-root-view-controller-programmatically-in-xcode-11/ ”

For iOS 13
In SceneDelegate.swift 

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options `connectionOptions: UIScene.ConnectionOptions) {`

// If this scene's self.window is nil then set a new UIWindow object to it.
self.window = self.window ?? UIWindow()

// Set this scene's window's background color.
self.window!.backgroundColor = UIColor.red

// Create a ViewController object and set it as the scene's window's root view controller.
self.window!.rootViewController = ViewController()

// Make this scene's window be visible.
self.window!.makeKeyAndVisible()

guard scene is UIWindowScene else { return }
}