swift - 如何在 Swift Playgrounds 中获得弹出对话框

Question

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 站点)

但是，无论我尝试什么，self 标记总是 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)

Answer 1

警报需要从 View Controller 中呈现。 than 意味着它会出现在助理编辑器内的模拟器中:

例子:

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)