How do I get a popup dialog box in Swift Playgrounds

问题

I was wondering how to get a dialog box to popup in Swift Playgrounds (yes must be in Playgrounds) I've tried the following code (directly from the AppleDevs site)

However, no matter what I try, the self tag always throws an error. Can anyone help me with this?

import UIKit
let alert = UIAlertController(title: "My Alert", message: "This is an alert.", preferredStyle: .alert) 
alert.addAction(UIAlertAction(title: NSLocalizedString("OK", comment: "Default action"), style: .default, handler: { _ in 
    NSLog("The \"OK\" alert occured.")
}))
self.present(alert, animated: true, completion: nil)

回答1:

Alerts need to be presented from a view controller. than means its going to show up in the simulator inside the assistant editor:

Example:

import UIKit
import PlaygroundSupport

let alert = UIAlertController(title: "My Alert", message: "This is an alert.", preferredStyle: .alert)
alert.addAction(UIAlertAction(title: NSLocalizedString("OK", comment: "Default action"), style: .default, handler: { _ in
    NSLog("The \"OK\" alert occured.")
}))
let v = UIViewController()
PlaygroundPage.current.liveView = v
v.present(alert, animated: true, completion: nil)

来源：https://stackoverflow.com/questions/55127152/how-do-i-get-a-popup-dialog-box-in-swift-playgrounds