swift - UserDefaults 在新发布时重置

Question

我有一个程序可以在用户按下播放按钮时播放不同的音频剪辑。对于要播放的音频，信用值必须大于 1。我尝试如下使用 UserDefaults，但它似乎每次都在重置。

class ViewController: UIViewController,.....
    var dataCredit = 3

    ....

    @IBAction func playsound(_ sender: Any) {
        defaults.set(dataCredit, forKey: "credits")

        credit = defaults.integer(forKey: "credits")

        if credit > 0 {
            feedLabel.text = "you have credits)"
            dataCredit = dataCredit - 1
            defaults.set(dataCredit, forKey: "credits")
            dataCredit = defaults.integer(forKey: "credits")
        } else if credit == 0 {
            feedLabel.text = "you dont have Credit\(startCredit)"
        }

这是我目前拥有的。每次我重新启动应用程序时，dataCredit 都会回到 3，并且它不会记住我存储的值。

Answer 1

那是因为您总是调用 defaults.set(dataCredit, forKey: "credits") 作为操作中的第一件事。你是这样做的:

class ViewController: UIViewController,.....

....


@IBAction func playsound(_ sender: Any) {
    if let credit = defaults.integer(forKey: "credits"), credit > 0 {
        feedLabel.text = "you have credits)"
        dataCredit = dataCredit - 1
        defaults.set(dataCredit, forKey: "credits")
        dataCredit = defaults.integer(forKey: "credits")
    } else if credit == 0 {
        feedLabel.text = "you dont have Credit\(startCredit)"
    }
}

---

更新:

要为积分设置初始值，我建议在 AppDelegate - didFinishLaunchingWithOptions 方法中进行:

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    // ...

    UserDefaults.standard.register(defaults: ["credits" : 3])

    // ...

    return true
}