Firebase IOS Google Sign in: Change views after successfully signed in

user_7080673 0
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I'm trying to build my first IOS App and trying to implement Firebase Google sign-in following the documentation located here: https://firebase.google.com/docs/auth/ios/google-signin. The issue is trying to change views if a user has successfully signed in. I have tried several solutions regarding this problem from other Stack overflow posts with none seeming to work. I believe this is because of the new sceneDelegate file which the other solutions don't have to take into account as they're using previous versions of XCode.

The Google sign-in is implemented in the App Delegate and the specific code that actually tries to authenticate a user (In the App delegate) is here: 

func sign(_ signIn: GIDSignIn!, didSignInFor user: GIDGoogleUser!, withError error: Error?) {
  // ...
  if let error = error {
    // ...
    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 {
    // ...
    return
  }
  // User is signed in
  // Here i want to change views
}

}

Once the user is signed in how do I change views? I have tried everything I can find and everything seems to not work or crash the app.

Any help is much appreciated

firebase swift xcode ios
3 Answers

You can use this in your SignIn function in the AppDelegate:

let nextVC= UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "YourViewController") as! YourViewController
window?.rootViewController = nextVC
user_86752820

Here is an example, how can you do it in your LoginVC:

class LoginViewController: UIViewController {

  override func viewDidLoad() {

    super.viewDidLoad()

    GIDSignIn.sharedInstance().delegate = self

    GIDSignIn.sharedInstance()?.presentingViewController = self

  }
}

This is what I have added in the viewDidLoad method. After that, I have created a custom button which inherits to UIButton. I have created that button programmatically but you can just use @IBOutlet weak var googleB: UIButton!. Then, on that button's tap, you can add this:

@IBAction func googleBTap(_ sender: UIButton) {

    GIDSignIn.sharedInstance().signIn()
}

Then, I have created the extension for GIDSignInDelegate.

extension LoginViewController: GIDSignInDelegate {

 func sign(_ signIn: GIDSignIn!, didSignInFor user: GIDGoogleUser!, withError error: Error?) {

    if let error = error {

        print(error)

        return
    }

    guard let email = user.profile.email else { 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)
      return
    }

    //If login is successful then add
   self.navigationController.pushViewController(nextVC(), animated: true) 
   //OR
   self.performSegue() //<-- Whatever goes in here, I don't use these methods as I create views programitacally, but you can use it here and move to next view 
}

 }

}

Well, this is one way, but as your app goes bigger it is better to create a FirebaseHelper class and you are going to use a lot of common methods like fetchProviders, signIn for Google, Facebook, Apple sign-ins. So, you can write one function which can fetch the credential and log in the user, that will be optimized then.

user_91175340

First you set your segue from LoginViewControllerto HomeViewController and set identifier for your segue to loginToHome.

            if error == nil {
                print("User signed in")
                self.performSegue(withIdentifier: "loginToHome", sender: self)
            }
user_44422540
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