ios - 传递的 Segue 变量在加载后保持清除

Question

所以我一直致力于学习 swift，我遇到了让我卡住了一段时间的问题。我使用序列将数据从第一个 Controller 传递到第二个 Controller 。

当我打印变量 onLoad 时，它会打印出传递的正确值，但是在我执行另一个函数(单击红色按钮)后，它不会打印出传递的值，而是打印出空白值。

var Level = 0;
var userId: String = "";
var clanId: String = "";
override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view.
    print(userId); //prints 97
    print(clanId); //prins 2
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}
@IBAction func redButtonClick(sender: AnyObject) {
     print(userId); //prints ""
    print(clanId); //prins ""
}

正如您在代码中看到的那样，它似乎非常简单，但显然我不知道它是如何工作的，因为在加载之后变量中没有任何内容。

感谢大家的帮助!

----------------编辑--------------------

更改值 userId: String = "test"更改了值 clanId: String = "test"

它现在在 onload 函数中打印出来

 print(userId)
 print(clanId)

 results:
 97
 2
 test
 test

----------------添加------------

@IBAction func loginButton(sender: AnyObject) {
  self.performSegueWithIdentifier("dashboard", sender: self);
}

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if(segue.identifier == "dashboard")
        {
            let dutydash:dashboardController  = segue.destinationViewController as! dashboardController;
            dutydash.userId = self.userId;
           dutydash.clanId = self.clanId;
        }
}

Answer 1

下面是一个工作示例，确保您的数据已在 prepareForSegue 中设置。

class prevClass: UIViewController{

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if segue.identifier == "nextView" {
            let destinationVC = segue.destinationViewController as! NextView
            destinationVC.userId = "77789";
            destinationVC.clanId = "Awesome Clan"

        }
    }
    @IBAction func next(sender: AnyObject) {
        self.performSegueWithIdentifier("nextView", sender: self)

    }
}

class NextView: UIViewController {

    var userId: String!
    var clanId: String!

    override func viewDidLoad() {
    }

    @IBAction func redButtonClick(sender: AnyObject) {
        print(userId);
        print(clanId);
    }
}