带有用户输入的JavaFX数学应用程序

Question

我正在尝试制作一个小而简单的应用程序，询问基本的数学问题，并等待用户输入检查并输出“正确”或“不正确”。我到达的问题是按下按钮时激活检查过程。有时代码会运行并执行除了运行检查过程之外的所有操作，但是我也遇到了一个问题，即代码卡在循环中而不会加载。

import java.util.Random;
import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ListChangeListener;
import javafx.stage.Stage;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.ListView;
import javafx.scene.control.TextField;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.VBox;

public class Main extends Application 
{
    final Button enterbutton = new Button("Enter");
    int ans = 0;
    final ListView<String> console = new ListView<String>(FXCollections.<String>observableArrayList());
    final TextField textbox = new TextField();  

    public int init(Stage firstStage)
    {
        Group root = new Group();
        firstStage.setScene(new Scene (root));

        VBox box = new VBox(10);

        int firstNumber = 0, secondNumber = 0, answer = 0, signNumber = 0, count = 0;
        Random rnd1 = new Random();
        Random rnd2 = new Random();
        Random rnd3 = new Random();

        firstNumber = rnd1.nextInt(100);
        secondNumber = rnd2.nextInt(100);
        signNumber = rnd3.nextInt(3);

        console.getItems().addListener(new ListChangeListener<String>()
        {
            public void onChanged(Change<? extends String> change)
            {
                while (change.next())
                {
                    if (change.getList().size() > 10)
                    {
                        change.getList().remove(0);
                    }
                }
            }
        });

        answer = Question(firstNumber, secondNumber, signNumber, count);

        console.getItems().add(firstNumber + " " + secondNumber + " " + signNumber);

        console.getItems().add(answer + " ");

        box.getChildren().addAll(textbox, enterbutton, console);
        root.getChildren().add(box);

        return answer;
    }

    @Override
    public void start(Stage primaryStage) throws Exception
    {
        int guessCounter = 0;

        init(primaryStage);
        primaryStage.show();
    }

    public int Question (int num1, int num2, int num3, int counter)
    {       
        while (counter == 0)
        {
            switch(num3)
            {
            case 0:
                ans = num1 + num2;
                break;
            case 1:
                ans = num1 - num2;
                break;
            case 2:
                ans = num1 * num2;
                break;
            default:
                ans = 0;
                break;
            }
            counter = 1;
        }

        return ans;
    }

    public boolean GuessCheck()
    {
        int userInput = 0, actualAnswer = 0;

        actualAnswer = ans;

        if (enterbutton.isPressed())
        {
            userInput = Integer.parseInt(textbox.toString());

            if (userInput == actualAnswer)
            {
                console.getItems().add("Correct");
            }
            else if (userInput != actualAnswer)
            {
                console.getItems().add("Incorrect");
            }
        }

        return true;
    }

    public void main(String[] args) 
    {
        launch(args);
    }
}