将文本值从一个视图控制器传送到另一个视图控制器

Posted 2023-03-17

【中文标题】将文本值从一个视图控制器传送到另一个视图控制器

【英文标题】：Taking text values from one view controller to another

【发布时间】：2017-04-20 12:04:11

【问题描述】：

所以我试图让用户通过 Facebook 注册，所以他们会点击 facebook 按钮，授权我们的应用程序，然后将他们转到注册屏幕，其中填写了“电子邮件”和“全名”字段我们从 Facebook 图表请求中收到的值。但是，我无法让它工作。

这是 Facebook 按钮所在的第一个视图控制器

import UIKit
import FBSDKLoginKit

  //[Facebook, 2017]
class RegisterVC: UIViewController, FBSDKLoginButtonDelegate 
var fbLoginSuccess = false

var fbName:String!
var fbEmail:String!

//[Facebook, 2017]
override func viewDidLoad() 
    super.viewDidLoad()

    let loginButton = FBSDKLoginButton()
    view.addSubview(loginButton)
    loginButton.frame = CGRect(x: 82, y: 325, width: view.frame.width - 210, height: 59)

    loginButton.delegate = self


//[Facebook, 2017]
func loginButtonDidLogOut(_ loginButton: FBSDKLoginButton!) 
    print("Did log out of facebook")


//[Facebook, 2017]
func loginButton(_ loginButton: FBSDKLoginButton!, didCompleteWith result: FBSDKLoginManagerLoginResult!, error: Error!) 
    if error != nil 
        print(error)
        return
    
    print("Successfully logged in")

    FBSDKGraphRequest(graphpath: "/me", parameters: ["fields": "id, name, email"]).start (connection, result, err) in
        if err != nil 
            print("Failed to start graph request", err)
            return
         else 
            /*guard let data = result as? [String:Any] else return

            let fbEmail = data["email"] as! String
            let fbName  = data["name"] as! String

            print(fbEmail)
            print(fbName)

            func prepare(for segue: UIStoryboardSegue, sender: Any?) 
                let vc = segue.destination as? CreateAccountVC
                vc!.emailTxtValue = self.fbName
                vc!.fullnameTxtValue = self.fbEmail
                */
            

        guard let data = result as? [String:Any] else return

        let fbEmail = data["email"] as! String
        let fbName  = data["name"] as! String

        print(fbEmail)
        print(fbName)

        func prepare(for segue: UIStoryboardSegue, sender: Any?) 
            if let vc = segue.destination as? CreateAccountVC 
            vc.emailTxtValue = self.fbName
            vc.fullnameTxtValue = self.fbEmail
            
        


        print(result)
    

    performSegue(withIdentifier: "regSegue", sender: RegisterVC.self)



//override func prepare(for segue: UIStoryboardSegue, sender: Any?) 
    //get destination view an set the fullname



    //performSegue(withIdentifier: "regSegue", sender: RegisterVC.self)

//



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






 

这是下一个视图控制器，其文本字段应显示从 Facebook 获取的信息

import UIKit

class CreateAccountVC: UIViewController 

var emailTxtValue: String?
var fullnameTxtValue: String?

@IBOutlet weak var usernameTxt: UITextField!
@IBOutlet weak var emailTxt: UITextField!
@IBOutlet weak var passwordTxt: UITextField!
@IBOutlet weak var fullnameTxt: UITextField!

override func viewDidLoad() 
    //fullname.text = fbName
    //email.text = fbEmail
    super.viewDidLoad()
    emailTxt.text = emailTxtValue
    fullnameTxt.text = fullnameTxtValue
    print(emailTxtValue)
    print("here")
    print(fullnameTxtValue)




func isValidEmail(emailTxt:String) -> Bool 
    // print("validate calendar: \(testStr)")
    let emailRegEx = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]2,"
    let emailTest = NSPredicate(format:"SELF MATCHES %@", emailRegEx)
    return emailTest.evaluate(with: emailTxt)


/*func isValidPassword(passwordTxt:String) -> Bool 
    let passwordRegEx = "8,"
    let passwordTest = NSPredicate(format:"SELF MATCHES %@", passwordRegEx)
    return passwordTest.evaluate(with: passwordTxt)
 */

func isValidUsername(usernameTxt:String) -> Bool 
    let usernameRegEx = "[a-z0-9_-]5,16"
    let usernameTest = NSPredicate(format:"SELF MATCHES %@", usernameRegEx)
    return usernameTest.evaluate(with: usernameTxt)


//[Idigov, 2017]
@IBAction func create(_ sender: AnyObject) 
    if usernameTxt.text!.isEmpty || passwordTxt.text!.isEmpty || emailTxt.text!.isEmpty || fullnameTxt.text!.isEmpty 

        usernameTxt.attributedPlaceholder = NSAttributedString(string: "username", attributes: [NSForegroundColorAttributeName: UIColor.red])
        emailTxt.attributedPlaceholder = NSAttributedString(string: "email", attributes:[NSForegroundColorAttributeName: UIColor.red])
        passwordTxt.attributedPlaceholder = NSAttributedString(string: "password", attributes: [NSForegroundColorAttributeName: UIColor.red])
        fullnameTxt.attributedPlaceholder = NSAttributedString(string: "fullname", attributes: [NSForegroundColorAttributeName: UIColor.red])

        let alertController = UIAlertController(title: "Error", message: "At least one of the values entered was not valid", preferredStyle: UIAlertControllerStyle.alert)
        alertController.addAction(UIAlertAction(title: "Okay", style: UIAlertActionStyle.default, handler:nil))
        self.present(alertController, animated: true, completion: nil)
        // if there is text within any of the textboxes it will attempt to register

     else if
        isValidEmail(emailTxt: emailTxt.text!) == false 
        let alertController = UIAlertController(title: "Error", message: "The email entered is not valid", preferredStyle: UIAlertControllerStyle.alert)
        alertController.addAction(UIAlertAction(title: "Okay", style: UIAlertActionStyle.default, handler:nil))
        self.present(alertController, animated: true, completion: nil)

     /*else if isValidPassword(passwordTxt: passwordTxt.text!) == false
            let alertController = UIAlertController(title: "Error", message: "The password entered must be at least 8 characters long", preferredStyle: UIAlertControllerStyle.alert)
            alertController.addAction(UIAlertAction(title: "Okay", style: UIAlertActionStyle.default, handler:nil))
            self.present(alertController, animated: true, completion: nil)

     */else if isValidUsername(usernameTxt: usernameTxt.text!) == false 
        let alertController = UIAlertController(title: "Error", message: "Your username must be 5 to 16 characters long and can only contain letters, numbers, underscores or hyphens", preferredStyle: UIAlertControllerStyle.alert)
        alertController.addAction(UIAlertAction(title: "Okay", style: UIAlertActionStyle.default, handler:nil))
        self.present(alertController, animated: true, completion: nil)
    

    //[Idigov, 2017]
    else


        let url = NSURL(string: "https://cgi.soic.indiana.edu/~team7/register.php")!

        let request = NSMutableURLRequest(url: url as URL)

        request.httpMethod = "POST"

        let body = "username=\(usernameTxt.text!.lowercased())&password=\(passwordTxt.text!)&email=\(emailTxt.text!)&fullname=\(fullnameTxt.text!)"
        request.httpBody = body.data(using: String.Encoding.utf8)

        URLSession.shared.dataTask(with: request as URLRequest as URLRequest, completionHandler:  (data:Data?, response:URLResponse?, error:Error?) -> Void in

            if error == nil 
                DispatchQueue.main.async(execute: 

                    do 
                        let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSDictionary
                        guard let parseJSON = json else 
                            print("Error while parsing")
                            return
                        

                        let id = parseJSON["id"]

                        if id != nil && response != nil 
                            print(parseJSON)
                        



                     catch 
                        print("Caught an error \(error)")
                    
                )

             else 
                print("error: \(error)")
            

        ).resume()
        let alertController = UIAlertController(title: "Registered", message: "Account Successfully Registered! Please Log In", preferredStyle: UIAlertControllerStyle.alert)
        let okay = UIAlertAction(title: "Okay", style: .default, handler: _ in CATransaction.setCompletionBlock(
            self.performSegue(withIdentifier: "accountSuccess", sender: nil))
            )
        alertController.addAction(okay)
        //alertController.addAction(UIAlertAction(title: "Okay", style: UIAlertActionStyle.default, handler:nil))
        self.present(alertController, animated: true, completion: nil)
    
    //performSegue(withIdentifier: "accountSuccess", sender: CreateAccountVC.self)

如果有人可以帮助我找到一个很棒的解决方案！谢谢！

【问题讨论】：

prepare(for segue:.. 方法应该在loginButton(_ loginButto... 方法之外

【参考方案1】：

您需要将prepareForSegue 方法放到类级别，而不是在任何其他方法内，您还需要在完成块内而不是在完成块外调用performSegue。如下更改您的代码。

//[Facebook, 2017]
func loginButton(_ loginButton: FBSDKLoginButton!, didCompleteWith result: FBSDKLoginManagerLoginResult!, error: Error!) 
    if error != nil 
        print(error)
        return
    
    print("Successfully logged in")

    FBSDKGraphRequest(graphPath: "/me", parameters: ["fields": "id, name, email"]).start (connection, result, err) in
        if err != nil 
            print("Failed to start graph request", err)
            return
         else 
             guard let data = result as? [String:Any] else return
             self.performSegue(withIdentifier: "regSegue", sender: data)
        
    


override func prepare(for segue: UIStoryboardSegue, sender: Any?) 
    if let vc = segue.destination as? CreateAccountVC,
    let dic = sender as? [String:Any] 
        let fbEmail = dic["email"] as! String
        let fbName  = dic["name"] as! String
        vc.emailTxtValue = fbEmail
        vc.fullnameTxtValue = fbName
    

【讨论】：

另外补充一点，他没有改变 self.fbEmail 和 self.fbName 的值，而是声明了新的常量和 ，然后在 prepareForSegue 他发送空的 self.fbName 和 self .fb电子邮件

@JaafarBarek 不需要，因为我将数据作为发件人传递，所以现在它将通过将发件人转换为字典来访问prepareforsegue，就像我在解决方案中建议的那样

我在 performSegue 行收到一个错误，提示“在闭包中隐式使用 'self'；使用 'self。”使捕获语义明确。”知道为什么会这样吗？

@jmoney11944 只需添加self. 和performSegue，也可以查看编辑后的答案

天啊，非常感谢你们。我欠你们一杯酒

【参考方案2】：

你已经全局声明了 2 个变量

var fbName:String!

var fbEmail:String!

当你给它赋值时，你正在创建与 , 相同的变量，

let fbEmail = data["email"] as! String

let fbName  = data["name"] as! String

所以你只需要从 fbEmail 和 fbName 中删除 let 就可以为另一个 View Controller 获取价值