swift - 如何从成功登录到第二页 - "warning attempt to present on while a presentation is in progress"错误

Question

如何在成功验证登录后转到我的第二页？

我已经从登录页面 View Controller (不是登录按钮)拉出一个 segue 到下一页，并将该 segue 命名为“nextPage”。 (如果我从登录按钮继续，那么单击该按钮将允许所有登录继续进行，而无需对其进行测试)。当我从登录页面继续时，它会正确检查详细信息，但在成功登录后不会继续到下一页，而是我收到控制台错误“警告:在演示过程中尝试演示!”

代码是

   @IBAction func loginButtonTapped(sender: AnyObject) {

       let userEmail = userEmailTextField.text;
    let userPassword = userPasswordTextField.text;
    let userEmailStored = NSUserDefaults.standardUserDefaults().stringForKey("userEmail");
    let userPasswordStored = NSUserDefaults.standardUserDefaults().stringForKey("userPassword");
    if userEmailStored == userEmail && userPasswordStored == userPassword {
        // Login successful
        // Display an alert message
        displayMyAlertMessage("Login successful. Thank you");
        NSUserDefaults.standardUserDefaults().setBool(true,forKey:"isUserLoggedIn");
        NSUserDefaults.standardUserDefaults().synchronize();
        print("login success!")
        self.dismissViewControllerAnimated(true, completion:nil);
        self.performSegueWithIdentifier("nextPage", sender: self);


    } else if userEmailStored != userEmail {
        // Login unsuccessful (email incorrect)
    NSUserDefaults.standardUserDefaults().setBool(false,forKey:"isUserLoggedIn");
        print("login unsuccessful. Incorrect email.")
        // Display an alert message
        displayMyAlertMessage("Incorrect login details.");
        return;
    } else if userPasswordStored != userPassword {
        // Login unsuccessful (password incorrect)
        // Display an alert message
        displayMyAlertMessage("Incorrect login details");
        //return;
    NSUserDefaults.standardUserDefaults().setBool(false,forKey:"isUserLoggedIn");
        print("login unsuccessful. Incorrect password.")


    }

登录页面出现在初始“ protected ”登录/注销屏幕之后，作为 ViewController.swift 使用此代码

     override func viewDidAppear(animated: Bool)
{

    let isUserLoggedIn = NSUserDefaults.standardUserDefaults().boolForKey("isUserLoggedIn");


    if(!isUserLoggedIn)
    {
        self.performSegueWithIdentifier("loginView", sender: self);
    }


}


@IBAction func logoutButtonTapped(sender: AnyObject) {

    NSUserDefaults.standardUserDefaults().setBool(false,forKey:"isUserLoggedIn");
    NSUserDefaults.standardUserDefaults().synchronize();

    self.performSegueWithIdentifier("loginView", sender: self);


}

Answer 1

我确实建议对此采取不同的方法。

如果您将 storyboardID 设置为 LoginViewController，您可以直接在 AppDelegate 中覆盖 protected 页面检查。

例如你可以尝试这样做

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
[...]

    let isUserLoggedIn = NSUserDefaults.standardUserDefaults().boolForKey("isUserLoggedIn")

if isUserLoggedIn  {

        let storyboard = UIStoryboard(name: "Main", bundle: NSBundle.mainBundle())
        let vc = storyboard.instantiateViewControllerWithIdentifier("IDYOUSETBEFORE")

        window.rootViewController = vc
        return
}

为了轻松处理这种情况，我最近设法发布了一个 pod，看看 StoryboardEnum lib