如何通过 2 个视图控制器传递 textfield.text 数据

Question

当用户在 ViewController 中将两个文本字段（passName 和 passPhone）作为 textField.text 输入后，我尝试将它们传递给我的第三个视图控制器，因为我需要它来引用 firebase 数据库子名称，但每次我运行它给我一个零返回值？我不明白为什么值不通过

performSegue 应该将 textfield.text 传递给下一个视图控制器，因为在 override func prepare 中我设置了它

错误代码：（在代码中查找位置）

线程 1：致命错误：在隐式展开可选值时意外发现 nil

// 视图控制器

@IBOutlet weak var nameField: UITextField!
@IBOutlet weak var numberField: UITextField!
@IBAction func linkTapped(_ sender: Any) {
    if (nameField.text != nil && numberField.text != nil) {
         if error != nil {
                   //code
                } else {
                    self.performSegue(withIdentifier: "code", sender: self) 
                }
            }
        }

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    let vc = verificationCodeViewController()
    vc.passName = self.nameField.text
    vc.passPhone = self.numberField.text
    nameField.endEditing(true)
    numberField.endEditing(true)
}

// 验证CodeViewController

var passName: String!
var passPhone: String!

@IBAction func Login(_ sender: Any) {
    if (code.text! != "") {
        let defaults = UserDefaults.standard
        let credential: PhoneAuthCredential = PhoneAuthProvider.provider().credential(withVerificationID: defaults.string(forKey: "authVID")!, verificationCode: code.text!)
        Auth.auth().signIn(with: credential) { (user, error) in
            if error != nil {
                print("error: \(String(describing: error?.localizedDescription))")
            } else {
                print("Phone Number: \(String(describing: user?.user.phoneNumber))")
                let userInfo = user?.user.providerData[0]
                print("Provider ID: \(String(describing: userInfo?.providerID))")
                self.performSegue(withIdentifier: "logged", sender: Any?.self)
            }
        }
    }
}

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    let vc = RankedClubScreen()
    vc.passName = self.passName
    vc.passPhone = self.passPhone
}

// RankedClubScreen -- ViewController

var passName: String!
var passPhone: String!

@IBAction func signOutFunction(_ sender: Any) {
    do {
        try Auth.auth().signOut()
        let ref = Database.database().reference().child("Online Users")
        print(self.passName + self.passPhone) // Thread 1: Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value
        ref.child(self.passName + self.passPhone).removeValue()

        self.view.window!.rootViewController?.dismiss(animated: true, completion: nil)
    } catch let error {
        print("not signed in...", error)
    }
}

Answer 1

你的问题是创建一个新的 vc 而不是在这里使用 segue 目的地

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
  let vc = VerificationCodeViewController()

这里

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
   let vc = RankedClubScreen()

那就这么写吧

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
  let vc = segue.destination as! VerificationCodeViewController
  vc.//// set this 

也让其他的segue也这样做

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