Swift func to show alert dialog in AppDelegate or ViewController

Was trying to show an alert dialog in a project’s AppDelegate.swift and ViewController.swift and decided to move it to a function in a separate utility class. Main issue was how to make it work as the class was a plain Swift class – self.present() could be used inside ViewController, self.window?.rootViewController?.present() could be used inside AppDelegate, but a plain Swift class?

Here’s my humble and simple solution, adapted from this StackOverflow answer. Just a note that AppDelegate may need to declare a var window = UIWindow?.

//  Util.swift
import UIKit

 * Common utility functions
class Util {     
     * Show alert dialog
     * @param title Dialog title
     * @param message Dialog message
     * @return void
    static func showAlert(_ title: String, _ message: String) {
        let alert = UIAlertController(
            title: title, 
            message: message, 
            preferredStyle: UIAlertControllerStyle.alert

            title: "OK", 
            style: UIAlertActionStyle.default, 
            handler: nil

            animated: true, 
            completion: nil