ios - 如何使用 UserDefaults.standard 在 Swift 3.0 中保持会话？

Question

我有两 (2) 个 swift 3.0 文件。

编辑：

我的目标是在登录成功后保持 ViewController 处于活动状态/出现。我想在点击注销按钮时保持 LoginVC 处于活动状态。

一切正常，例如发布和读取 json 数据。

编辑：

ViewController 在登录时成功激活，但是当我点击注销按钮时，停止并再次构建它，ViewController 仍然没有关闭。它应该重定向到 LoginVC。

我认为我的UserDefaults.standard代码可能有问题。

我的代码如下

ViewController.swift

import UIKit
class ViewController: UIViewController {

    override func viewDidLoad() { super.viewDidLoad() }

    override func viewDidAppear(_ animated: Bool) {

        let isUserLoggedIn = UserDefaults.standard.bool(forKey: "isUserLoggedIn")
        if(!isUserLoggedIn){
            self.performSegue(withIdentifier: "loginview", sender: self)
        }
    }
    @IBAction func logoutData(_ sender: Any) {
        UserDefaults.standard.set(true, forKey: "isUserLoggedIn");
        UserDefaults.standard.synchronize();
        self.performSegue(withIdentifier: "loginview", sender: self)
    }
}

LoginVC.swift

import UIKit
class LoginVC: UIViewController {
    @IBOutlet var _login: UITextField!
    @IBOutlet var _pass: UITextField!
    var login: String!
    var pass: String!

    override func viewDidLoad() { super.viewDidLoad() }

    @IBAction func loginData(_ sender: Any) {  
        login = _login.text
        pass  = _pass.text

        if(login == "" || pass == "") {
            return
        }
        else {
            let url     = URL(string: "http://localhost/login.php")
            let session = URLSession.shared

            let request = NSMutableURLRequest(url: url! as URL)
            request.httpMethod = "POST"

            let paramToLogin = "login=\(login!)&pass=\(pass!)"
            request.httpBody = paramToLogin.data(using: String.Encoding.utf8)

            let task = session.dataTask(with: request as URLRequest, completionHandler: {
                (data, response, error) in
                if error != nil {
                    return
                }
                else {
                    do {
                        if let json = try JSONSerialization.jsonObject(with: data!) as? [String: String]
                        {
                            DispatchQueue.main.async {
                                let success  = Int(json["message"]!)

                                if(success == 1){
                                    UserDefaults.standard.set(true, forKey: "isUserLoggedIn")
                                    UserDefaults.standard.synchronize();
                                    self.dismiss(animated: true, completion: nil)
                                    return
                                }
                            }
                        }
                    }
                    catch { }
                }
            })
            task.resume()
        }
    }
}

Answer 1

在注销期间的代码中，值“true”也存储在 UserDefaults 中。我认为这可能是问题所在。

Answer 2

let loginStroyBoard = UIStoryboard(name:"Login", bundle: nil)
let businessLoginViewController = loginStroyBoard.instantiateViewController(withIdentifier: "BusinessLoginViewController") as! BusinessLoginViewController
let refreshAlert = UIAlertController(title: "Log Out", message: "Are You Sure to Log Out ? ", preferredStyle: UIAlertControllerStyle.alert)

refreshAlert.addAction(UIAlertAction(title: "Confirm", style: .default, handler: { (action: UIAlertAction!) in
    self.present(businessLoginViewController, animated: true, completion: nil)

DispatchQueue.main.async {
    UserDefaults.standard.removeObject(forKey: "isFirstTime")
    UserDefaults.standard.removeObject(forKey: "isLogIn")
    UserDefaults.standard.removeObject(forKey: "uid")
    UserDefaults.standard.removeObject(forKey: "hash")
    UserDefaults.standard.removeObject(forKey: "storeadminid")
    UserDefaults.standard.removeObject(forKey: "adminhash")
    UserDefaults.standard.removeObject(forKey: "store_id")
    UserDefaults.standard.removeObject(forKey: "isLogIn")
    UserDefaults.standard.removeObject(forKey: "login_id")
    UserDefaults.standard.removeObject(forKey: "password")
    UserDefaults.standard.setValue(false, forKey: "islogout")
    }

    //self.tabBarController?.tabBar.resignFirstResponder()
}))

refreshAlert.addAction(UIAlertAction(title: "Cancel", style: .default, handler: { (action: UIAlertAction!) in
    refreshAlert .dismiss(animated: true, completion: nil)
}))

present(refreshAlert, animated: true, completion: nil)

}

我也会用它来注销。
你可以试试这个，我会用我的单元格注销按钮来做。