AddingViewcontroller manually into the stack swift 3 - ios

Question

I am coding the sign out button in my app.This is the flow of my app.
SplashvwController -> secretCodeViewController ->
LoginviewController -> DashboardViewController
in this DashboardViewController I have the signOut button.
My app has single sign in facility once user logged, next time when he opens the app,
SplashvwController -> DashboardViewController
I want to prompt the user to Loginviewcontroller whenever he clicks the sign out button.
Question
When user going through path 1 I can simply do popviewcontroller to go back to the previous viewcontroller. But when user go though the 2nd path,
how can I add the Loginviewcontroller manually into my
viewcontrollers stack to perform the same operation?
How can I check whether the LoginviewController exists in my current Viewcontrollers stack?
Please help me

Answer 1

I think, the below code helps you,
for (var i = 0; i < self.navigationController?.viewControllers.count; i++) {
if(self.navigationController?.viewControllers[i].isKindOfClass(Loginviewcontroller) == true) {
self.navigationController?.popToViewController(self.navigationController!.viewControllers[i], animated: true)
break;
}
}
To add a ViewController Manually , check the code below..
let navigation = mainStoryboard.instantiateViewController(withIdentifier: "LoginViewController") as! LoginViewController
let nav = UINavigationController(rootViewController: navigation)
appdelegate.window!.rootViewController = nav

Answer 2

Set the storyboard reference identifier for a LoginViewController on the Main.Storyboard file.
Whenever you want to show the LoginViewController just call the function
func launchLoginView() {
if let loginVC: LoginViewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewControllerWithIdentifier("LoginStoryboardID") as? LoginViewController {
// .instantiatViewControllerWithIdentifier() returns AnyObject! this must be downcast to utilize it
// LoginStoryboardID is the reference id for login view controller.
self.presentViewController(loginVC, animated: true, completion: nil).
// OR
//UIApplication.shared.keyWindow?.rootViewController = loginVC
}
}
Landing screen based on the User login status.
In AppDelegte.swift
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
let isLoggedAlready = //Get the login status
if isLoggedAlready == true {
if let dashBoardVC: DashboardViewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewControllerWithIdentifier("DashboardStoryboardID") as? DashboardViewController {
//Already logged in then directly launch dashboard vc.
//change the code based on your needs
window?.rootViewController = dasbBoardVC
}
}
// Otherwise let it go as flow 1
return true
}
}