无论凭据是不是正确，都会触发 Segue

Posted 2023-02-23

【中文标题】无论凭据是不是正确，都会触发 Segue

【英文标题】：Segue is triggered whether credentials are correct or not无论凭据是否正确，都会触发 Segue

【发布时间】：2015-01-22 04:42:34

【问题描述】：

我试图仅在凭据正确的情况下执行 segue。否则应该有一个警报，说明“凭据不正确”。当我运行应用程序时，segue 正在执行并转到下一个视图，即凭据是否正确/不正确。在 Storyboard 中，我以模态方式连接到 AccountViewController。为什么会发生这种情况？

class ViewController: UIViewController, NSURLConnectionDelegate 


@IBOutlet weak var emailTextField: UITextField!
@IBOutlet weak var passwordTextField: UITextField!

var token: NSString = ""


override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) 

        var accountViewController = segue.destinationViewController as AccountViewController
        accountViewController.token = self.token



private let api_key = ""

func logIn() 


    var email: NSString = emailTextField.text
    var pass: NSString = passwordTextField.text

    // Remove characters from the custom character set with the custom set

    let customEncodedSet: NSMutableCharacterSet = NSCharacterSet.URLHostAllowedCharacterSet().mutableCopy() as NSMutableCharacterSet
    customEncodedSet.removeCharactersInString("!*'();:@&=+$,/?%#[]")

        var encodedEmail = email.stringByAddingPercentEncodingWithAllowedCharacters(customEncodedSet)
        var encodedPass = pass.stringByAddingPercentEncodingWithAllowedCharacters(customEncodedSet)


    var url = "https://www.photoshelter.com/psapi/v3/mem/authenticate?api_key=\(api_key)&email=\(encodedEmail!)&password=\(encodedPass!)&mode=token"


    var baseURL:NSURL? = NSURL(string: url)
    var request: NSMutableURLRequest? = NSMutableURLRequest(URL: baseURL!)
    var session = NSURLSession.sharedSession()
    var task = session.dataTaskWithRequest(request!, completionHandler:  (data, response, error) -> Void in
        dispatch_async(dispatch_get_main_queue(),  () -> Void in


            if response == nil 
                UIAlertView(title: "PhotoShelter", message: "No internet connection", delegate: nil, cancelButtonTitle: "Cancel").show()
             else 
                var responseObject: AnyObject? = NSJSONSerialization.JSONObjectWithData(data, options: nil, error: nil)
                var status: AnyObject? = responseObject?.objectForKey("status")

                if status as String != "ok" 
                    UIAlertView(title: "PhotoShelter", message: "Invalid Credentials", delegate: nil, cancelButtonTitle: "OK").show()

                 else 

                    var tokenString: AnyObject? = responseObject?.objectForKey("data")
                    self.token = tokenString?.objectForKey("token") as NSString
                    self.performSegueWithIdentifier("loginSuccessSegue", sender: self)
                

            

        )
    )
    task.resume()



@IBAction func signInPressed(sender: AnyObject) 

    if self.emailTextField.text == "" || self.passwordTextField.text == "" 
        UIAlertView(title: "PhotoShelter", message: "Empty Username or Password", delegate: nil, cancelButtonTitle: "OK").show()


     else 
        logIn()
    

【问题讨论】：

在您的故事板中，您的登录按钮是否直接链接到下一个视图控制器？

如果是这样，也许这个答案将有助于解释你应该做什么：***.com/a/20690072/2274694

【参考方案1】：

您应该实现shouldPerformSegueWithIdentifier:sender: 方法来控制是否要执行segue。

【讨论】：

@LyndseyScott，我只看到prepareForSegue 方法，我错了吗？

是的，shouldPerformSegueWithIdentifier:sender: 在 login() 的 dataTaskWithRequestBlock 中，如果状态 == ok 则调用

我也看不到shouldPerformSegueWithIdentifier，但是块中的逻辑应该足够了-Lyndsey 的其他评论可能是问题所在-除了@ 之外，还有从按钮到segue 的直接链接IBA动作

哦，是的，你们都说得对。没注意，不好意思。我的意思是 performSegueWithIdentifier。