求用鼠标绘图代码

Question

Java web start contains an example,download it from java.sun.com

Answer 1

import java.awt.*;
import java.awt.event.*;
import java.util.*;public class Test extends Frame
{
   public static void main(String[] args)
   {
      new Test();
   }
   public Test()
   {
      this.addWindowListener(new WindowAdapter(){public void windowClosing(WindowEvent e){dispose();System.exit(0);}});
      this.setSize(300,300);
      this.setLocation(300,0);
      this.add(new Draw());
      this.show();
   }
   protected void processWindowEvent(WindowEvent event)
   {
      super.processWindowEvent(event);
      if(event.getID() == WindowEvent.WINDOW_CLOSING)
      {
         System.exit(0);
      }
   }
}
class Draw extends Canvas
{
   int x1=-1;
   int y1=-1;
   int x2=-1;
   int y2=-1;
   public Draw()
   {
      this.setBackground(Color.white);
      this.addMouseListener(new MyMouseListener(this));
      this.addMouseMotionListener(new MyMouseMotionListener(this));
   }
   public void paint(Graphics g)
   {
      if(x1==-1 || y1==-1)
      {
         x1=x2;
         y1=y2;
      }
      g.drawLine(x1,y1,x2,y2);
      x1=x2;
      y1=y2;
   }
   public void update(Graphics g)
   {
      this.paint(g);
   }
}
class MyMouseListener implements MouseListener
{
   Draw draw;
   public MyMouseListener(Draw draw)
   {
      this.draw=draw;
   }
   public void mouseClicked(MouseEvent e)
   {
      //System.out.println("mouseClicked");
   }
   public void mouseEntered(MouseEvent e)
   {
      //System.out.println("mouseEntered");
   }
   public void mouseExited(MouseEvent e)
   {
      //System.out.println("mouseExited");
   }
   public void mousePressed(MouseEvent e)
   {
      //System.out.println("mousePressed");
      draw.x1=-1;
      draw.y1=-1;
   }
   public void mouseReleased(MouseEvent e)
   {
      //System.out.println("mouseReleased");
      draw.x1=draw.x2;
      draw.y1=draw.y2;
   }
}
class MyMouseMotionListener implements MouseMotionListener
{
   Draw draw;
   public MyMouseMotionListener(Draw draw)
   {
      this.draw=draw;
   }
   public void mouseDragged(MouseEvent e)
   {
      //System.out.println("mouseDragged");
      draw.x2=e.getX();
      draw.y2=e.getY();
      draw.repaint();
   }
   public void mouseMoved(MouseEvent e)
   {
      //System.out.println("mouseMoved");
   }
}