Java键盘练习小游戏

键盘练习小游戏，要求：
编写小程序，按下键为数字时窗口背景编程蓝色，其他键为淡蓝色，释放键时背景变为红色，输入字符x时推出程序。界面如图所示

我写了一段代码，望采纳，按照要求，输入x可退出程序

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

public abstract class ChangeColour extends JFrame implements KeyListener {
    private String str = "";
    public ChangeColour() {
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setLocationRelativeTo(null);
        setSize(500, 500);
        setResizable(false);
        setVisible(true);
        new Thread() {
            public void run() {
                while (true) {
                    try {
                        if(str=="F")
                            System.exit(0);
                        sleep(10);
                        if(str=="b")
                        {
                            getContentPane().setVisible(false);
                            setBackground(Color.CYAN);
                            setVisible(true);
                        }
                        if(str=="B")
                        {
                            getContentPane().setVisible(false);
                            setBackground(Color.blue);
                            setVisible(true);
                        }
                        if(str=="R")
                        {
                            getContentPane().setVisible(false);
                            setBackground(Color.red);
                            setVisible(true);
                        }
                    } catch (Exception e) {
                    }
                }
            }
        }.start();
        this.addKeyListener(this);
    }
    public static void main(String[] args) {
        new ChangeColour() {
            @Override
            public void keyTyped(KeyEvent e) {
            }
        };
    }
    public void keyPressed(KeyEvent e) {
        if (e.getKeyCode() == KeyEvent.VK_X) {
            str = "F";
            return;
        }
        if (e.getKeyCode() == KeyEvent.VK_NUMPAD0||e.getKeyCode() == KeyEvent.VK_NUMPAD1||
            e.getKeyCode() == KeyEvent.VK_NUMPAD2||e.getKeyCode() == KeyEvent.VK_NUMPAD3||
            e.getKeyCode() == KeyEvent.VK_NUMPAD4||e.getKeyCode() == KeyEvent.VK_NUMPAD5||
            e.getKeyCode() == KeyEvent.VK_NUMPAD6||e.getKeyCode() == KeyEvent.VK_NUMPAD8||
            e.getKeyCode() == KeyEvent.VK_NUMPAD9||e.getKeyCode() == KeyEvent.VK_NUMPAD7||
            e.getKeyCode() == KeyEvent.VK_0||e.getKeyCode() == KeyEvent.VK_1||
            e.getKeyCode() == KeyEvent.VK_2||e.getKeyCode() == KeyEvent.VK_3||
            e.getKeyCode() == KeyEvent.VK_4||e.getKeyCode() == KeyEvent.VK_5||
            e.getKeyCode() == KeyEvent.VK_6||e.getKeyCode() == KeyEvent.VK_8||
            e.getKeyCode() == KeyEvent.VK_9||e.getKeyCode() == KeyEvent.VK_7) {
            str = "B";
            return ;
        }
        else
        str = "b";
    }
    public void keyReleased(KeyEvent e) {
        str = "R";
    }
}

运行截图：

这很简单吖～都有思路了要不试着写一下

import java.awt.Color;

import java.awt.Container;

import java.awt.event.KeyAdapter;

import java.awt.event.KeyEvent;

import java.awt.event.WindowAdapter;

import java.awt.event.WindowEvent;

import javax.swing.JDialog;

public class MyTest {

static JDialog dialog = new JDialog();

Container cp = new Container();

public static void main(String[] args) {

MyTest mytest = new MyTest();

dialog.setSize(300, 200);

dialog.setLocationRelativeTo(null);

dialog.setTitle("测试");

dialog.addKeyListener(mytest.new MyKeyListener());

dialog.setDefaultCloseOperation(JDialog.DO_NOTHING_ON_CLOSE);

dialog.addWindowListener(new WindowAdapter() {

public void windowClosing(WindowEvent e) {

dialog.dispose();

}

});

dialog.setVisible(true);

}

class MyKeyListener extends KeyAdapter {

public void keyPressed(KeyEvent e) {

char key = e.getKeyChar();

cp = dialog.getContentPane();

cp.setLayout(null);

switch (key) {

case 'r':

cp.setBackground(Color.red);

break;

case 'g':

cp.setBackground(Color.green);

break;

case 'b':

cp.setBackground(Color.blue);

break;

}

System.out.println("你按了【" + key + "】键");

}

}

}