如何在 Swift Playgrounds 中获得弹出对话框

How do I get a popup dialog box in Swift Playgrounds

我想知道如何在 Swift Playgrounds 中弹出对话框(是的,必须在 Playgrounds 中)我已经尝试了以下代码(直接来自AppleDevs 网站)

但是,无论我尝试什么,self 标签 总是 会引发错误。谁能帮我解决这个问题?

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)

需要从视图控制器中显示警报。 than 意味着它将出现在助理编辑器内的模拟器中:

示例:

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)