import java.awt.*;
import javax.swing.*;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
public class MyBall{
public static void main(String[] args){
JFrame w = new JFrame();
w.setSize(300, 400);
MyPanel mp = new MyPanel();
w.add(mp);
w.addMouseMotionListener(mp);
mp.addMouseMotionListener(mp);
w.setVisible(true);
}
}
class MyPanel extends JPanel implements MouseMotionListener{
int x = 30;
int y = 30;
public void paint(Graphics g){
super.paint(g);
g.fillOval(x, y, 20, 20);
}
@Override
public void mouseDragged(MouseEvent arg0){
//鼠标拖动
x = arg0.getX();
y = arg0.getY();
repaint();
}
@Override
public void mouseMoved(MouseEvent arg0){
}
}
以下是小球自由下落。
import java.awt.*;
import javax.swing.*;
public class MyBall{
public static void main(String[] args){
JFrame w = new JFrame();
w.setSize(300, 400);
MyPanel mp = new MyPanel();
w.add(mp);
Thread t = new Thread(mp);
t.start();
w.setVisible(true);
}
}
class MyPanel extends JPanel implements Runnable{
int x = 30;
int y = 30;
public void paint(Graphics g){
super.paint(g);
g.fillOval(x, y, 20, 20);
}
public void run(){
while(true){
y++;
if(y>400){
y = 0;
}
try{
Thread.sleep(20);
}catch(Exception e){
}
repaint();
}
}
}
