Java从入门到精通15-方向键控制小球实例

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

/**
* Created by Administrator on 2015-10-15.
*/
public class ArrawKey extends JFrame {
CirclePanel circlePanel = null;

public static void main(String[] args) {
ArrawKey arrawKey = new ArrawKey();
}

//构造函数
public ArrawKey() {
circlePanel = new CirclePanel();
this.add(circlePanel);
this.addKeyListener(circlePanel);
this.setSize(640, 480);
this.setTitle("方向键控制小球实例");
this.setLocationRelativeTo(null);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setVisible(true);
}
}

//定义面板
class CirclePanel extends JPanel implements KeyListener {
int x = 10;
int y = 10;

public void paint(Graphics graphics) {
super.paint(graphics);
graphics.fillOval(x, y, 10, 10);
}

@Override
public void keyTyped(KeyEvent e) {

}

@Override
public void keyPressed(KeyEvent e) {
switch (e.getKeyCode()) {
case KeyEvent.VK_DOWN:
y += 10;
break;
case KeyEvent.VK_UP:
y -= 10;
break;
case KeyEvent.VK_RIGHT:
x += 10;
break;
case KeyEvent.VK_LEFT:
x -= 10;
break;
}
this.repaint();
}

@Override
public void keyReleased(KeyEvent e) {

}
}