如何将UITextField字符串从SecondViewController传递到模型类中的数组？

Question

我正在创建一个带有模型和两个视图控制器的闪存卡应用程序。在第一个场景中，我显示问题和答案，并在一系列问题和答案之间循环。问题和答案数组存储在Model类中。第二个场景/视图控制器的目的是不能通过编辑UITextField中的文本来编辑问题和答案，并且在按下OK按钮之后，问题和答案数组将更新为TextFields中的文本。

在第二个ViewController中编辑“问题”和“答案”文本字段时，必须将对这些字符串的更改应用于第一个场景中使用的同一FlashCardModel对象。

如何使用questionTextField的值更新模型类中的问题数组？

//  FlashCardModel.swift
//  TabbedFlashCards
//
//
//
//

import Foundation

class FlashCardModel {
    var currentQuestionIndex = 0;
    var questions = ["What is 1*7?", "What is 2*7?", "What is 3*7?"]
    var answers = ["7", "14", "21"]

    init(){
        //Any useful Constructor code would go here
    }

    func getNextQuestion() -> String{
        currentQuestionIndex = currentQuestionIndex + 1;
        if(currentQuestionIndex >= questions.count){
            currentQuestionIndex = 0;
        }
        return questions[currentQuestionIndex]
    }

    func getAnswer() -> String{
        return answers[currentQuestionIndex]
    }

    func getCurrentQuestion() -> String{
        return questions[currentQuestionIndex]
    }

    func setCurrentQuestion(pString : String){
        questions[currentQuestionIndex] = pString
    }

    func setCurrentAnswer(pString : String){
        answers[currentQuestionIndex] = pString
    }
}//End of model

//
//  SecondViewController.swift
//  TabbedFlashCards
//
//

import UIKit

class SecondViewController: UIViewController {
    // the reference to our AppDelegate:
    var appDelegate: AppDelegate?
    // the reference to our data model:
    var myFlashCardModel: FlashCardModel?

    @IBOutlet weak var questionTextField: UITextField!
    @IBOutlet weak var answerTextField: UITextField!

    @IBAction func buttonOKAction(sender: AnyObject) {
        self.appDelegate = UIApplication.shared.delegate as? AppDelegate
        self.myFlashCardModel = self.appDelegate?.myFlashCardModel

        var text: String = questionTextField.text!

        //myFlashCardModel?.setCurrentQuestion(pString: editQuestion)
        //print ("self.questionTextField.text = \(self.questionTextField.text)")
        //print ("self.answerTextField.text = \(self.answerTextField.text)")
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        self.questionTextField.text = "Question"
        self.answerTextField.text = "Answer"
    }
}