swift - iCloud keyValue 使我的游戏崩溃

Question

尝试使用键值对从 iCloud 检索一个整数。有人可以向我解释为什么这会因错误而崩溃:

 '[<NSUbiquitousKeyValueStore 0x170287e40> valueForUndefinedKey:]: this class is not key value coding-compliant for the key current.'

它在我之前的项目中运行良好。

 var iCloudKeyStore: NSUbiquitousKeyValueStore = NSUbiquitousKeyValueStore()

 func loadSavedData() {

    if let cloudCurrent = iCloudKeyStore.value(forKey: "current") as! Int? { /* <-------- Crashes on this line */
        print("Current Level Found From iCloud: \(cloudCurrent)")
        currentLevel = cloudCurrent
    }else{
        print("No Current Level Found")
    }

    if let cloudAchieved = iCloudKeyStore.value(forKey: "achieved") as! Int? {
        print("Current Level Found From iCloud: \(cloudAchieved)")
        levelAchieved = cloudAchieved
    }else{
        print("No Achieved Level Found")
    }

Answer 1

value(forKey:) 用于动态访问对象的实例变量。 IE。键值编码。

该对象上没有名为“current”的实例变量。您想要访问存储在商店中的值，根据文档，应该使用 object(forKey:) 来完成。