ios - 我想在第一次打开应用程序时创建提醒

Question

我想在设备上第一次打开应用程序时创建警报，但我在代码方面遇到了一些问题。这就是我到目前为止所拥有的，任何帮助将不胜感激

    // alert first time app is opened
    // making of alert

    let alert = UIAlertController(title: "Navigation", message: "Tap Right Hand Side of Screen For Next Quote, Left Hand Side To Go Back", preferredStyle: UIAlertControllerStyle.alert)

    //add ok button
    alert.addAction(UIAlertAction(title: "Dismiss", style: UIAlertActionStyle.default, handler: nil))

    // detect if first launch
    let launchedBefore = UserDefaults.standard.bool(forKey: "launcedBefore")
    if launchedBefore {
    }
    else {
        self.present(alert, animated: true, completion: nil)
        UserDefaults.standard.set(true, forKey: "launchedBefore")
    }

这是我试图放置代码的地方

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

Answer 1

launchedBefore 键中有拼写错误将其更改为:

let launchedBefore = UserDefaults.standard.bool(forKey: "launchedBefore")