Source Code : How to create a virtual desktop in your application

How to create a virtual desktop in your application

This Java Swing tip illustrates a method of using the background of your application as a virtual desktop. This code uses JDesktopPane which is a container (usually for JInternalFrames) that simulates a desktop. Typically, the user will create JInternalFrames and place them in a JDesktopPane. The user can then interact with JInternalFrames like they usually would with JFrames. The actions (minimize, maximize, close, etc) are done by using a DesktopManager that is associated with the JDesktopPane.

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

public class DesktopTest extends JFrame {
  public DesktopTest()
  {
  super( "Using a JDesktopPane" );

  JMenuBar bar = new JMenuBar();
  JMenu addMenu = new JMenu( "Add" );
  JMenuItem newFrame = new JMenuItem( "Internal Frame" );
  addMenu.add( newFrame );   
  bar.add( addMenu );
  setJMenuBar( bar );   

  final JDesktopPane theDesktop = new JDesktopPane();
  getContentPane().add( theDesktop );
   
  newFrame.addActionListener(
  new ActionListener() {
  public void actionPerformed( ActionEvent e ) {
  JInternalFrame frame =
  new JInternalFrame(
  "Internal Frame",
  true, true, true, true );

  Container c = frame.getContentPane();
  MyJPanel panel = new MyJPanel();

  c.add( panel, BorderLayout.CENTER );
  frame.setSize(
  panel.getImageWidthHeight().width,
  panel.getImageWidthHeight().height );
  frame.setOpaque( true );
  theDesktop.add( frame );
  }
  }
  );

  setSize( 500, 400 );
  show();
  }

  public static void main( String args[] )
  {   
  DesktopTest app = new DesktopTest();

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

class MyJPanel extends JPanel {
  private ImageIcon imgIcon;

  public MyJPanel()
  {
  imgIcon = new ImageIcon( "java-tip.gif" );
  }

  public void paintComponent( Graphics g )
  {
  imgIcon.paintIcon( this, g, 0, 0 );
  }

  public Dimension getImageWidthHeight()
  {
  return new Dimension( imgIcon.getIconWidth(),
  imgIcon.getIconHeight() );  
  }
}