Question

我有以下问题。几个星期后我尝试学习编码，我的实际项目是登录页面。这个概念如下：当我打开应用程序时，有登录屏幕，用户可以登录。这项工作到目前为止。登录后，用户将被定向到另一个视图。有一个注销按钮。这就是问题所在。当我单击该按钮时，用户将被注销（我通过打印出当前用户来证明这一点并获得了nil）并再次返回到登录屏幕。但是，当他现在点击没有或有错误数据的登录按钮时，他再次进入屏幕，尽管它出现了错误信息。我的错在哪里？这是我的代码：

import UIKit
import Parse

class ViewController: UIViewController {


    func displayAlert(title:String, message:String){
        let alert = UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.alert)
        alert.addAction(UIAlertAction(title: "OK", style: .default, handler: { (action) in self.dismiss(animated: true, completion: nil)}))
        self.present(alert, animated: true, completion: nil)
    }

    @IBOutlet weak var benutzer: UITextField!

    @IBOutlet weak var passwort: UITextField!

    @IBAction func ButtonLogin(_ sender: Any) {
        // Hier die Loginfunktion
        let activityIndiaktor = UIActivityIndicatorView(frame: CGRect(x: 0, y: 0, width: 50, height: 50))
        activityIndiaktor.center = self.view.center
        activityIndiaktor.hidesWhenStopped = true
        activityIndiaktor.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.gray
        view.addSubview(activityIndiaktor)
        activityIndiaktor.startAnimating()
        UIApplication.shared.beginIgnoringInteractionEvents()


        PFUser.logInWithUsername(inBackground: benutzer.text!, password: passwort.text!, block: { (user, error) in
            if user == nil {
                var errortext = "Unknown Error! Try again!"
                if let error = error {
                    errortext = error.localizedDescription
                }
                self.displayAlert(title: "Login error", message: errortext)

            }else{

                print("Login done!")

                let viewController:UIViewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "Main") as! UIViewController
                self.present(viewController, animated: true, completion: nil)

                // UIApplication.shared.endIgnoringInteractionEvents()
                //  activityIndiaktor.stopAnimating()
            }

            activityIndiaktor.stopAnimating()
            UIApplication.shared.endIgnoringInteractionEvents()
            return
        })



    }

    override func viewDidLoad() {
        super.viewDidLoad()


        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
}
    }

这里是另一种观点：

import UIKit
import Parse

class MainViewController: UIViewController {

    @IBAction func Logout(_ sender: Any) {
        PFUser.logOut()
        let viewController:UIViewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "LoginSeite") as! UIViewController
        self.present(viewController, animated: true, completion: nil)

    }
    @IBOutlet weak var LabelWillkommen: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()

        let user = String(describing: PFUser.current()!.username!)



        LabelWillkommen.text = "Welcome \(user)!"


        // Do any additional setup after loading the view.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


    }

Answer 1

在MainViewController只需使用以下代码段

更改注销按钮操作即可

@IBAction func Logout(_ sender: Any) {
        PFUser.logOut()
        if  PFUser.current()?.sessionToken == nil {
        let viewController:UIViewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "LoginSeite") as! UIViewController
        self.present(viewController, animated: true, completion: nil)
        }
    }

希望这会对你有所帮助

Answer 2

我再次检查了一切。我找不到错误。 Logout工作，但if情况仍然认为，用户已登录。我可以重新加载View或重新加载if语句或类似的东西吗？还是其他想法？

修复注销功能

2 个答案: