1 import java.awt.BorderLayout; 2 import java.awt.Graphics; 3 import java.awt.event.ActionEvent; 4 import java.awt.event.ActionListener; 5 import java.awt.event.ComponentEvent; 6 import java.awt.event.ComponentListener; 7 8 import javax.swing.JButton; 9 import javax.swing.JFrame; 10 import javax.swing.JPanel; 11 12 public class Test_16 extends JFrame implements ActionListener{ 13 private JButton j1 = new JButton("left"); 14 private JButton j2 = new JButton("right"); 15 private JButton j3 = new JButton("up"); 16 private JButton j4 = new JButton("down"); 17 private JP j = new JP(); 18 private int x =100,y =200; 19 20 public Test_16(){ 21 JPanel J = new JPanel(); 22 J.add(j1);J.add(j2);J.add(j3);J.add(j4); 23 j1.addActionListener(this); 24 j2.addActionListener(this); 25 j3.addActionListener(this); 26 j4.addActionListener(this); 27 add(J,BorderLayout.SOUTH); 28 add(j,BorderLayout.CENTER); 29 } 30 31 public static void main(String[] args) { 32 // TODO Auto-generated method stub 33 Test_16 t1 = new Test_16(); 34 t1.setTitle("Test_16"); 35 t1.setSize(400,400); 36 t1.setFocusable(true); 37 t1.setLocationRelativeTo(null); 38 t1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 39 t1.setVisible(true); 40 } 41 42 class JP extends JPanel{ 43 private int radius = 5; 44 45 protected void paintComponent(Graphics g){ 46 super.paintComponent(g); 47 g.drawOval(x, y, 2*radius, 2*radius); 48 } 49 } 50 public void actionPerformed(ActionEvent e) { 51 // TODO Auto-generated method stub 52 if(e.getSource() == j1) 53 { 54 x -= 20; 55 repaint(); 56 } 57 else if(e.getSource() == j2){ 58 x += 20; 59 repaint(); 60 }else if(e.getSource() == j3){ 61 y -= 20; 62 repaint(); 63 }else if(e.getSource() == j4){ 64 y += 20; 65 repaint(); 66 } 67 } 68 }