Swift display an alert after tapping on notification - ios

Question

So what i am trying to achieve is when a notification launch and the user tap on it, an Alert controller should appear with 2 options. However, when the app launch from the notification tap, nothing appears.
These codes are inside the AppDelegate.swift file
func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: #escaping () -> Void) {
showAlert()
}
func showAlert() {
let alert = UIAlertController(title: "Confirm", message: "Confirm?", preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "No", style: .destructive, handler: nil))
alert.addAction(UIAlertAction(title: "Yes", style: .default, handler: nil))
window?.rootViewController?.present(alert, animated: true, completion: nil)
}

Answer 1

var topVC: UIWindow? = UIWindow(frame: UIScreen.main.bounds)
topVC?.rootViewController = UIViewController()
let alert = UIAlertController(title: "Alert", message: "Notification Received", preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "OK", style: .cancel) { _ in
// action OK
})
topVC?.makeKeyAndVisible()
topVC?.rootViewController?.present(alert, animated: true, completion: nil)

Answer 2

Try this:
func showAlert() {
var alertController = UIAlertController(title: "Confirm", message: "Confirm?", preferredStyle: UIAlertControllerStyle.alert)
var okAction = UIAlertAction(title: "Yes", style: UIAlertActionStyle.Default) {
UIAlertAction in
// action
}
var cancelAction = UIAlertAction(title: "No", style: UIAlertActionStyle.Cancel) {
UIAlertAction in
// action
}
alertController.addAction(okAction)
alertController.addAction(cancelAction)
self.window?.rootViewController?.presentViewController(alertController, animated: true, completion: nil)
}

Answer 3

I think you are calling the func showAlert() from the wrong place.
When the app launch from the notification tap, the app gets an event in
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool
So you should try this,
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
//Handle remote notification event on app launch
if let remoteNotification = launchOptions?[UIApplication.LaunchOptionsKey.remoteNotification] {
showAlert()
}
}