如何在 Swift 3.0 中使用 Storyboard 在控制器之间传递数据？

Question

swift 3.0 中如何使用 UIStoryboard 在控制器之间传递数据？

我创建了 login (LoginViewController) 和 ma​​in (ViewController) 页面，如果用户没有注销，应用程序会在其中保持活动状态。

到目前为止它有效。

我有这些 JSON 值 "login" 需要从 LoginViewController 传递到 ViewController

有些人建议使用perform and prepare segue。

它可以工作，但只有从 LoginViewController 发送的值才能显示。

当页面 ViewController 处于活动状态时（当我重建/清理应用程序时），ViewController 没有保存数据。

我的目标是在页面处于活动状态时保留 ViewController 中的“登录”数据，并在页面注销时清除“登录”数据。

LoginViewController.swift

import UIKit
class LoginViewController: UIViewController {

    @IBOutlet var _loginLbl: UITextField!
    @IBOutlet var _pwLbl: UITextField!
    @IBOutlet var login_button: UIButton!

    @IBOutlet var outputLbl: UILabel!

    var login: String!
    var pw: String!

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

    @IBAction func loginData(_ sender: Any) {
        login = _loginLbl.text
        pw    = _pwLbl.text

            let url = URL(string: "http://localhost/login.php")
            let session = URLSession.shared

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

            let LoginDataToPost = "login=\(login!)&pw=\(pw!)"
            request.httpBody = LoginDataToPost.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 message = Int(json["message"]!)
                                let login   = json["login"]

                                if(message == 1) {
                                    UserDefaults.standard.set(true, forKey: "isUserLoggedIn")
                                    UserDefaults.standard.synchronize();
                                    self.dismiss(animated: true, completion: nil)

                                    let myViewController:ViewController = self.storyboard!.instantiateViewController(withIdentifier: "ViewController") as! ViewController
                                    let appDelegate = UIApplication.shared.delegate as! AppDelegate
                                    appDelegate.window?.rootViewController = myViewController
                                    appDelegate.window?.makeKeyAndVisible()

                                    self.outputLbl.text = login;

                                    return
                                }
                                else { }
                            }  
                        }  
                        else { }
                    } catch let jsonParse {}
                }
            })
            task.resume()
        }
    }
}

ViewController.swift

import UIKit
class ViewController: UIViewController {
    @IBOutlet var loginLbl: UILabel!
    var login: String!
    override func viewDidLoad() {
        super.viewDidLoad()
    let preferences = UserDefaults.standard

         if(preferences.object(forKey: "isUserLoggedIn") != nil){
            loginLbl.text = login
         }
         else {

         }
    }
    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(false, forKey: "isUserLoggedIn");
        UserDefaults.standard.synchronize();
        let loginViewController = self.storyboard!.instantiateViewController(withIdentifier: "loginview") as! LoginViewController
        let appDelegate = UIApplication.shared.delegate as! AppDelegate
        appDelegate.window?.rootViewController = loginViewController
        appDelegate.window?.makeKeyAndVisible()
    }

}

有什么想法吗？

谢谢。

Answer 1

您可以将值存储在 LoginViewController 的 NSUserDefaults 中。如下所示：

UserDefaults.standard.set(login, forKey: "loginJSONValue")

并像这样在ViewController中获取值（我假设该值是String）：

textField1.text = UserDefaults.standard.object(forKey: "loginJSONValue") as? String

LoginViewController.swift

import UIKit
class LoginViewController: UIViewController {

    @IBOutlet var _loginLbl: UITextField!
    @IBOutlet var _pwLbl: UITextField!
    @IBOutlet var login_button: UIButton!

    @IBOutlet var outputLbl: UILabel!

    var login: String!
    var pw: String!

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

    @IBAction func loginData(_ sender: Any) {
        login = _loginLbl.text
        pw    = _pwLbl.text

            let url = URL(string: "http://localhost/login.php")
            let session = URLSession.shared

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

            let LoginDataToPost = "login=\(login!)&pw=\(pw!)"
            request.httpBody = LoginDataToPost.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 message = Int(json["message"]!)
                                let login   = json["login"]

                                if(message == 1) {
                                    UserDefaults.standard.set(true, forKey: "isUserLoggedIn")
                                    UserDefaults.standard.set(login, forKey: "loginJSONValue")
                                    UserDefaults.standard.synchronize();
                                    self.dismiss(animated: true, completion: nil)

                                    let myViewController:ViewController = self.storyboard!.instantiateViewController(withIdentifier: "ViewController") as! ViewController
                                    let appDelegate = UIApplication.shared.delegate as! AppDelegate
                                    appDelegate.window?.rootViewController = myViewController
                                    appDelegate.window?.makeKeyAndVisible()

                                    self.outputLbl.text = login;

                                    return
                                }
                                else { }
                            }  
                        }  
                        else { }
                    } catch let jsonParse {}
                }
            })
            task.resume()
        }
    }
}

ViewController.swift

import UIKit
class ViewController: UIViewController {
    @IBOutlet var loginLbl: UILabel!
    var login: String!
    override func viewDidLoad() {
        super.viewDidLoad()
    let preferences = UserDefaults.standard

         if(preferences.object(forKey: "isUserLoggedIn") != nil){

// let isUserLoggedIn = UserDefaults.standard.bool(forKey: "isUserLoggedIn")
            let isUserLoggedIn = UserDefaults.standard.object(forKey: "isUserLoggedIn") as Bool
    // your login data is below. do what you want to do
                login = UserDefaults.standard.object(forKey: "loginJSONValue") as String
                if(!isUserLoggedIn){
                    self.performSegue(withIdentifier: "loginview", sender: self)
                }
            loginLbl.text = login
         }
         else {

         }
    }
    override func viewDidAppear(_ animated: Bool) {

        }

        @IBAction func logoutData(_ sender: Any) {
            UserDefaults.standard.set(false, forKey: "isUserLoggedIn");
// After logging out, you can set empty to login data.
UserDefaults.standard.set("", forKey: "loginJSONValue");
            UserDefaults.standard.synchronize();
            let loginViewController = self.storyboard!.instantiateViewController(withIdentifier: "loginview") as! LoginViewController
            let appDelegate = UIApplication.shared.delegate as! AppDelegate
            appDelegate.window?.rootViewController = loginViewController
            appDelegate.window?.makeKeyAndVisible()
        }

    }

Answer 2

需要在应用重启时再次调用登录服务并传递数据。或者您可以将数据存储在 UserDefault 中并重复使用。

UserDefaults.standard.set(login, forKey: "loginResponse")

您可以将数据从一个控制器传递到另一个控制器，如下所示：

  let myViewController:ViewController = self.storyboard!.instantiateViewController(withIdentifier: "ViewController") as! ViewController
var loginResponse = UserDefaults.standard.get(forKey:"loginResponse")
myViewController.your_object = loginResponse