Displaying multiple images

[Bill Compton]

The application is to display a geographic map from a .gif and then draw vectors on top to show locations of features. Then the user can change the geographic location. A GIS will generate a new map .gif which must be read and displayed. The task of this code then is to show loading an image and then replacing with another image. The behavior (with Java 1.2 and 1.3) is that the first image is loaded and displayed but when it tries to replace the first image with the second image, the window does not change.
Can anyone correct my approach?
Thanks in advance.

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class post
{
    public static void main( String args[] )
    {
JFrame jframe = new JFrame( "Hello World" );
JPanel jp = new JPanel();
// Load and display the first image
JLabel jl = new JLabel( new ImageIcon( "map_small.gif" ) );
jp.add( jl );
jframe.getContentPane().add( jp );

jframe.setSize( 500 , 500 );
Msg("Painting first image");
jframe.setVisible( true );
try
{
    Thread.sleep( 3000 );
} catch ( InterruptedException ie )
{
}
// Remove first image and show second image    
jframe.getContentPane().remove( jp );
    
jl = new JLabel( new ImageIcon( "map.gif" ) );
jp.add( jl );
jframe.getContentPane().add( jp );
Msg( "Painting second image" );
jframe.repaint();
    
try
{
    Thread.sleep(3000);
} catch (InterruptedException ie)
{
}
System.exit( 0 );
    }
    static void Msg( String m ) { System.err.println( m ); }
}

[This message has been edited by Paul Wheaton (edited September 18, 2000).]

[paul wheaton]

I put a slash in your CODE statement so it could be more readable.

I think the problem is that you are using the thread that the VM needs to draw stuff.

[Jayakumar Thirumalai]

You may try
jframe.validate(); before repaint().
if you want the second image to overlap on first image, you may have to remove the icon from panel also.
You may also increase the sleep time from 3000 to 5000 or 6000. This will give some time for the image to load.
Jay

[Bill Compton]

The solution I have settled on is to invoke drawImage directly in the paint() method of the container. Thanks for the suggestions / help. Here's the skeleton that works:

import java.awt.*;
import javax.swing.*;
public class im2
{
    public static void main( String[] args )
    {
        myJFrame mjf = new myJFrame();
        mjf.loadImageMap("map_small.gif");
        mjf.show();
        try
        {
            Thread.sleep(3000);
        } catch (InterruptedException ie)
        {
        }
        mjf.loadImageMap("map.gif");
        mjf.repaint();
    }
}
class myJFrame extends JFrame
{
    Image im;
    public myJFrame()
    {
        setSize(500,500);
    }
    public void loadImageMap ( String imageFileName )
    {
        im = Toolkit.getDefaultToolkit().getImage( imageFileName );
    }
    public void paint(Graphics g)
    {
        g.drawImage(im, 0, 0, this);
    }
}