MouseMove problem in JPanel

Question

Hello I am writing an applet and I am calling a class which extends JPanel.
In the JPanel I am trying to create a rectangle (fillRect) which than I will be able to move using the method mouseMove().
I have been able to draw the rectangle on the panel which is in the applet but i havent succeded in moving the rectangle with mouseMove().
Could somebody please show me to implement the mouseMove correctly .

Answer 1

Here's a sloppy sort of example for you. It could be vastly improved, but it shows you one example of using a MouseMotionAdapter to change the state of your JPanel subclass.
Basically, you maintain a model - in this case, the location of your rectangle. When you get input from the mouse, you change the model appropriately. Then you need your view to be redrawn to show your new model. In this case, we just call repaint() and let Swing handle it. In other programs, you might have a loop continuously redrawing the view for you (but that's another story).
Cheers,
John
package moop;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import javax.swing.JPanel;
public class MyPanel extends JPanel  {
     /** the last known location of the corner of our rectangle  */
     private Point cornerPoint = new Point(0,0);
      * Constructor, giving us a chance to add a mouse motion listener.
     public MyPanel() {
          addMouseMotionListener(new MouseMotionAdapter() {
                * @see java.awt.event.MouseMotionListener#mouseMoved(java.awt.event.MouseEvent)
               public void mouseMoved(MouseEvent e) {
                    cornerPoint.x = e.getX() - 10;
                    cornerPoint.y = e.getY() - 10;
                    repaint();
      * Override the default method to draw a rectangle.
     public void paintComponent(Graphics g) {
          // let the superclass do it's stuff first
          super.paintComponent(g);          
          // draw a red rectangle
          g.setColor(Color.red);
          g.fillRect(cornerPoint.x, cornerPoint.y, 20, 20);
}