1.Отобразить вид предупреждения:
let alert = UIAlertController()
alert.title = "This is your title of the alert"
alert.message = "This is your question"
alert.addAction(UIAlertAction(title: "Answer one", style: .default , handler:{ (UIAlertAction)in
// Let's save the user's choice for later
UserDefaults.standard.set("UserChoseOptionOne", forKey: "myReallyImportantQuestion")
}))
alert.addAction(UIAlertAction(title: "Answer two", style: .default , handler:{ (UIAlertAction)in
// Let's save the user's choice for later
UserDefaults.standard.set("UserChoseOptionTwo", forKey: "myReallyImportantQuestion")
}))
alert.addAction(UIAlertAction(title: "Ask me later", style: .cancel, handler:{ (UIAlertAction)in
// Let's not do anything here.
// The user can't decide at the moment and let's ask the next time your app is opened again
}))
self.present(alert, animated: true, completion: nil)
2.По вашему мнению DidLoad
// Here we have to differentiate between three cases!
// Case 1: This is the very first time our dear user opened our cool app
// or
// Case 2: This is not the first time, we already asked our important question and we have an answer already!
// or
// Case 3: This is not the first time, the last time we asked our question, the user decided to choose later. Later is now!
if let option = UserDefaults.standard.string(forKey: "myReallyImportantQuestion") {
// Here we handle Case 2. Maybe you don't want to do anything here
// We already have the user's choice saved in option
// We can do whatever we want with that
}else{
// Here are the cases 1 and 3.
// In here you can paste the code from "1. Display an alert view"
// If you feel fancy today, you can also make a function out of "1. Display an alert view" and call it in here
}