moveboxwithcanvas.java

Java程序设计技巧与开发实例附书源代码。

import java.awt.*;
import java.awt.event.*;

public class MoveBoxWithCanvas
    extends Frame
    implements ActionListener
{
   private Button left = new Button("Left");
   private Button right = new Button("Right");
   private Button up = new Button("Up");
   private Button down = new Button("Down");
   public MoveBoxCanvas drawing = new MoveBoxCanvas();
   public MoveBoxWithCanvas()
   {
      super("Moving Box");
      setup();
      left.addActionListener(this);
      right.addActionListener(this);
      up.addActionListener(this);
      down.addActionListener(this);
      setSize(400, 400);
      show();
   }

   private void setup()
   {
      Panel buttons = new Panel();
      buttons.setLayout(new FlowLayout());
      buttons.add(up);
      buttons.add(down);
      buttons.add(left);
      buttons.add(right);
      setLayout(new BorderLayout());
      add("South", buttons);
      add("Center", drawing);
   }

   public void actionPerformed(ActionEvent e)
   {
      if (e.getSource() == up)
      {
         drawing.moveUp();
      }
      else if (e.getSource() == down)
      {
         drawing.moveDown();
      }
      else if (e.getSource() == left)
      {
         drawing.moveLeft();
      }
      else if (e.getSource() == right)
      {
         drawing.moveRight();
      }
      drawing.repaint();
   }

   public static void main(String args[])
   {
      MoveBoxWithCanvas mb = new MoveBoxWithCanvas();
   }
}