Rakesh Kumar Rakesh Kumar - 8 days ago 3
Swift Question

Swift App not starting at Initial ViewController Scene

I am currently making an app, that has the Google Sign In, implemented into the project, and I'm not sure why the app is not launching on the InitialViewController scene. Instead of starting at the initial scene, it is starting at my Login page. I think this may be happening because, I set it so that the ViewController.swift file is associated with the Login page and not the initial launching page.

Here is the code for my AppDelegate:

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:.
}


}


And ViewController

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.
}


}


Also here is a screenshot of my main.storyboard:

Main.Storyboard Screenshot

Answer

The reason why app is not starting at the InitialViewController specify in the storyboard is because of this window!.rootViewController = tabBarVC. By settings the rootViewController on window you actually override the specification set on the storyboard. Therefore it is ignored.

If you want to show the ViewController with the TheOracle label in the screenshot, you should be giving that ViewController a identifier. Lets call it OnboardingViewController.

Then you should update this:

if let tabBarVC = sb.instantiateViewController(withIdentifier: "LogInViewController") as? ViewController {
    window!.rootViewController = tabBarVC
}

to

if let tabBarVC = sb.instantiateViewController(withIdentifier: "OnboardingViewController") as? ViewController {
    window!.rootViewController = tabBarVC
}
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