多类GUI

Question

我一直在使用Random类在Java中使用基本的“猜我的数字”游戏，但我试图让我的第一个GUI有多个窗口。我遇到了一些我看不到的问题，我自己想出来，所以我来这里寻求帮助。

这是他的主要课程：

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.Random;

public class GuessMyNumber extends JFrame
{
    private JLabel lblIntro;
    private JLabel lblPrompt;
    private JTextField txtInput;
    private JButton btnSend;
    private JButton btnCustomize;
    private JTextField txtMin;
    private JTextField txtMax;
    private JButton btnSet;
    private ButtonListener btnListener;
    private boolean customize;
    private boolean game;
    private int min;
    private int max;
    private int dif;
    private int magicNum;
    private int num;
    private int guesses = 1;

    public GuessMyNumber()
    {
        super("Guess My Number");
        Container cp = getContentPane();
        setLayout(new FlowLayout());

        lblIntro = new JLabel("Welcome to Guess My Number");
        lblPrompt = new JLabel("Please enter your guess:");
        txtInput = new JTextField(15);
        btnSend = new JButton("Send");
        btnSend.addActionListener(new ButtonListener());

        btnCustomize = new JButton("Customize Range");
        btnCustomize.addActionListener(new ButtonListener());

        cp.add(lblIntro);
        cp.add(lblPrompt);
        cp.add(txtInput);
        cp.add(btnSend);
        cp.add(btnCustomize);


        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(500, 100);
        setVisible(true);
    }
    public static void main(String[]args)
    {
        GuessMyNumber foo = new GuessMyNumber();
    }
    public int getMagicNum(int min, int max)
    {
        Random g = new Random();
        if(customize)
        {
            dif = max - min;
            magicNum = g.nextInt(dif) + min + 1;
        }
        else
        {
            magicNum = g.nextInt(100) + 1;
        }
        return magicNum;
    }
    public String getFeedback(int guesses)
    {
        String feedback;
        if(guesses < 4 && guesses > 0)
            feedback = "Superstar";
        else if(guesses < 7 && guesses > 3)
            feedback = "Pretty Good";
        else if(guesses < 10 && guesses > 6)
            feedback = "Mediocre";
        else
            feedback = "Pathetic";
        return feedback;
    }
    private class ButtonListener implements ActionListener
    {
        public void actionPerformed(ActionEvent e)
        {
            Object clicked = e.getSource();
            if(clicked == btnCustomize)
            {
                customize = true;
                game = false;
                GUIUtil gui = new GUIUtil();
                min = gui.getMin();
                max = gui.getMax();
            }
            if(clicked == btnSend)
            {
                String feedback;
                if(!(customize))
                {
                    min = 1;
                    max = 100;
                    if(!(game))
                        magicNum = getMagicNum(min, max);
                    game = true;
                    num = Integer.parseInt(txtInput.getText());
                    if(num < magicNum)
                        JOptionPane.showMessageDialog(null, "Too low!");
                    else if(num > magicNum)
                        JOptionPane.showMessageDialog(null, "Too high!");
                    else
                    {
                        feedback = getFeedback(guesses);
                        JOptionPane.showMessageDialog(null, "Correct!!!\nYou guessed my number in " + guesses + " guesses!\n" + feedback);
                        guesses = 0;
                        game = false;
                    }
                    guesses++;
                }
                else
                {
                    if(!(game))
                        magicNum = getMagicNum(min, max);
                    game = true;
                    num = Integer.parseInt(txtInput.getText());;
                    if(num < magicNum)
                        JOptionPane.showMessageDialog(null, "Too low!");
                    else if(num > magicNum)
                        JOptionPane.showMessageDialog(null, "Too high!");
                    else
                    {
                        feedback = getFeedback(guesses);
                        JOptionPane.showMessageDialog(null, "Correct!!!\nYou guessed my number in " + guesses + " guesses!\n" + feedback);
                        guesses = 0;
                        game = false;
                    }
                    guesses++;
                }
            }

        }
    }
}

这是第二堂课：

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class GUIUtil extends JFrame
{
    private JTextField txtMin;
    private JTextField txtMax;
    private JButton btnSet;
    private ButtonListener btnListener;
    private int min;
    private int max;
    private boolean set = false;

    public GUIUtil()
    {
        super("Customization");
        Container cp = getContentPane();
        setLayout(new FlowLayout());

        txtMin = new JTextField("Min", 15);
        txtMax = new JTextField("Max", 15);
        btnSet = new JButton("Set");
        btnSet.addActionListener(new ButtonListener());
        cp.add(txtMin);
        cp.add(txtMax);
        cp.add(btnSet);
        setSize(190,125);
        setVisible(true);
    }
    public int getMin()
    {
        if(set = true)
        {
            set = false;
            return min;
        }
        else
        {
            min = 0;
            return min;
        }
    }
    public int getMax()
    {
        if(set = true)
        {
            set = false;
            return max;
        }
        else
        {
            max = 100;
            return max;
        }
    }
    private class ButtonListener implements ActionListener
    {
        public void actionPerformed(ActionEvent e)
        {
            min = Integer.parseInt(txtMin.getText());
            max = Integer.parseInt(txtMax.getText());
            set = true;
        }
    }
}

当我尝试自定义范围然后在第二个窗口打开时进行猜测以使对象保持活动状态时的错误如下：

Exception in thread "AWT-EventQueue-0" java.lang.IllegalArgumentException: n mus
t be positive
        at java.util.Random.nextInt(Unknown Source)
        at GuessMyNumber.getMagicNum(GuessMyNumber.java:66)
        at GuessMyNumber$ButtonListener.actionPerformed(GuessMyNumber.java:127)
        at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
        at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
        at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
        at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Sour
ce)
        at java.awt.Component.processMouseEvent(Unknown Source)
        at javax.swing.JComponent.processMouseEvent(Unknown Source)
        at java.awt.Component.processEvent(Unknown Source)
        at java.awt.Container.processEvent(Unknown Source)
        at java.awt.Component.dispatchEventImpl(Unknown Source)
        at java.awt.Container.dispatchEventImpl(Unknown Source)
        at java.awt.Component.dispatchEvent(Unknown Source)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
        at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
        at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
        at java.awt.Container.dispatchEventImpl(Unknown Source)
        at java.awt.Window.dispatchEventImpl(Unknown Source)
        at java.awt.Component.dispatchEvent(Unknown Source)
        at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
        at java.awt.EventQueue.access$200(Unknown Source)
        at java.awt.EventQueue$3.run(Unknown Source)
        at java.awt.EventQueue$3.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Sour
ce)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Sour
ce)
        at java.awt.EventQueue$4.run(Unknown Source)
        at java.awt.EventQueue$4.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Sour
ce)
        at java.awt.EventQueue.dispatchEvent(Unknown Source)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
        at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
        at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
        at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
        at java.awt.EventDispatchThread.run(Unknown Source)

Answer 1

尝试将GUIUtils声明为GuessNumber类的类成员。并在构造函数

中实例化它

public class GuessNumber {
    GUIUtil utils;

    public GuessNumber(){
        utils = new GUIUtils();
    }
}

并从actionPerformed()中删除它。我认为发生的事情是，当您在GUIUtils中创建actionPerformed()对象时，文本字段中没有初始数据。在创建GUIUtil对象之后，程序立即尝试从textFields获取没有值的输入。