Create toast when log out (iOS) - ios

Question

I'm working for an app that has users. One of the functionalities is to allow a user to log out and be redirected to the first page. I came across the problem when a user logs out, a toast message "You logged out" should be displayed on the first view of the app and receiving the command from a different page. Basically a toast message that can work with all the views, not only with the current one.
I managed to call a toast function after a user logs out but it won't show the message because the current view is dismissed before to have the chance showing it.
This is the function called:
func showToast(controller: UIViewController, message : String, seconds: Double) {
let alert = UIAlertController(title: nil, message: message, preferredStyle: .alert)
alert.view.backgroundColor = UIColor.black
alert.view.alpha = 0.6
alert.view.layer.cornerRadius = 15
controller.present(alert, animated: true)
DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + seconds) {
alert.dismiss(animated: true)
}
}

Answer 1

If you dont know which the current presented VC is you could use this extension here:
extension UIWindow {
func topViewController() -> UIViewController? {
var top = self.rootViewController
while true {
if let presented = top?.presentedViewController {
top = presented
} else if let nav = top as? UINavigationController {
top = nav.visibleViewController
} else if let tab = top as? UITabBarController {
top = tab.selectedViewController
} else {
break
}
}
return top
}
}
Then you can call it it this way:
if let topVC = UIApplication.shared.keyWindow?.topViewController() {
topVC.present(alert, animated: true)
}
Another option is that you pop/dismiss your viewcontroller after you dismissed your alert:
DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + seconds) {
alert.dismiss(animated: true)
// popViewController or dismiss here
}