JAVA Zeichenprogramm (nicht zu kompliziert!)

/*
   PaintShop first version
*/


import java.awt.*;
import java.awt.event.*;
import javax.swing.*;


/* -------------------------------
   Main Frame in program PaintShop
   -------------------------------*/
   public class PaintShop extends JFrame
                          implements MouseListener, MouseMotionListener {


   private JButton      button1;
   private JButton      button2;
   private FlowLayout   layout;


   private DrawingPanel drawingPanel;


   public PaintShop()
   {
      super( "PaintShop first version" );


      layout = new FlowLayout();


      Container c = getContentPane( );
      c.setLayout ( layout );


      button1      = new JButton("Button 1");
      button2      = new JButton("Button 2");


      drawingPanel = new DrawingPanel(0,0);


      addMouseListener(this);
      addMouseMotionListener(this);


      c.add(button1);
      c.add(button2);
      c.add(drawingPanel);


      setSize( 750, 500 );
      show();
   }


/* ------------------------------
   Listening for mouse activities
   ------------------------------*/
   public void mouseClicked ( MouseEvent e )
   {
   }


   public void mouseEntered ( MouseEvent e )
   {
   }


   public void mouseExited ( MouseEvent e )
   {
   }


   public void mousePressed ( MouseEvent e )
   {
      drawingPanel.setPaint();
   }


   public void mouseReleased ( MouseEvent e )
   {
      drawingPanel.setNotPaint();
   }


/* -----------------------------
   Listening for mouse movements
   -----------------------------*/
   public void mouseMoved ( MouseEvent e )
   {
   }


   public void mouseDragged ( MouseEvent e )
   {
      drawingPanel.setX( e.getX() );
      drawingPanel.setY( e.getY() );
      drawingPanel.paintComponent(getGraphics());
   }


/* ---------------------------------------
   Class DrawingPanel
   This Panel is used to draw a picture on
   ---------------------------------------*/
   private class DrawingPanel extends JPanel {
      private int       xValue;
      private int       yValue;
      private boolean   paint;


      public DrawingPanel(int x, int y) {
         xValue   = x;
         yValue   = y;
         paint    = false;
      }


      public void setX(int x) {
         xValue = x;
      }


      public void setY(int y) {
         yValue = y;
      }


      public void setPaint() {
         paint = true;
      }


      public void setNotPaint() {
         paint = false;
      }


      public void paintComponent( Graphics g ) {
         g.fillOval(xValue, yValue, 4, 4 );
      }
   }


/* -----------
   MainProgram
   -----------*/
   public static void main( String args[] )
   {
      PaintShop app = new PaintShop();


      app.addWindowListener(
         new WindowAdapter()
         {
            public void windowClosing( WindowEvent e )
            {
               System.exit( 0 );
            }
         }
      );
   }
}