Attempt to present alertcontroller whose view is not in window hierarchy - xcode

Question

I'm getting the following error in Swift 3:
Attempt to present alertcontroller whose view is not in window hierarchy
I have already referred to other posts on this topic to no avail. More specifically, I've implemented the change suggested in this post: AlertController is not in the window hierarchy
and I'm still receiving the same error.
What I've done is:
Create an AlertHelper.swift helper class:
class AlertHelper {
func showAlert(fromController controller: UIViewController) {
let alert = UIAlertController(title: "Please Try Again", message: "Email Already In Use", preferredStyle: .alert)
controller.present(alert, animated: true, completion: nil)
}
}
In my View Controller, under a function which is called when a button is pressed, I check to see if an email address entered by a user is already stored in my Firebase database, and if so, I try to present an "Email already in use" alert from the AlertHelper class:
Auth.auth().createUser(withEmail: email, password: password) { (user, error) in
if error != nil {
if let errCode = AuthErrorCode(rawValue: error!._code) {
switch errCode {
case .emailAlreadyInUse:
let alert = AlertHelper()
alert.showAlert(fromController: self)
return
default:
print("other error")
}
}
}
else {
// Inputs user email into database
self.ref.child("Users").child((user?.uid)!).setValue(["Email": email, "Location": ""])
self.performSegue(withIdentifier: "todorm", sender: self)
}
}
The database stuff works, the only thing that isn't appearing is the alert. Any ideas? Thanks!!

Answer 1

It's sort of a strange practice to subclass your alert into a separate class.
You should try making a method in your ViewController class
func showAlert() {
let alert = UIAlertController(title: "Please Try Again", message: "Email Already In Use", preferredStyle: .alert)
self.present(alert, animated: true, completion: nil)
}
Call the method using:
self.showAlert()