Re cardLayout

[rose deng]

Hi.
I have a panel whose layout manager is CardLayout. when i add a scrollpane to it, the scrollpane doesn't show.
what's wrong?
wait for your valuable help.

[Nathan Pruett]

Rose,
I am not sure exactly what you are trying to do since you didn't post any code, but I've built some test code to try the situation you are describing... try to plug a resonably big image into the test code and it should work... ( replace Washu_BG1.gif with the image of your choice... ) Hopefully, it will illustrate what you need.

import java.awt.*;
import java.awt.event.*;
public class ScrollPaneTest extends Frame
{
    // Constructor.
    ScrollPaneTest()
    {
        super( "ScrollPane Test" );
        Panel p = new Panel();
        CardLayout cl = new CardLayout();
        p.setLayout( cl );
        ScrollPane sp = new ScrollPane( );
        Image i = Toolkit.getDefaultToolkit().createImage( "Washu_BG1.gif" );
        // Washu_BG1.gif is a 400 x 300 image I had lying around in my directory...
        MediaTracker mt = new MediaTracker( this );
        // MediaTracker must be used so size of image will be known...
        mt.addImage( i, 0 );
        try
        {
            mt.waitForAll();
        }
        catch( InterruptedException x )
        {
            System.out.println( "MediaTracker interrupted!" );
        }
        ImageCanvas ic = new ImageCanvas( i );
        sp.add( ic );
        p.add( sp, "1" );
        add( p, BorderLayout.CENTER );
        addWindowListener( new WindowAdapter() {
            public void windowClosing( WindowEvent e )
            {
                System.exit( 0 );
            }
        } );
        cl.show( p, "1" );
    }
    public static void main( String[] args )
    {
        ScrollPaneTest spt = new ScrollPaneTest();
        spt.setSize( 200,200 );
        // Size of frame is smaller than size of image so scrollbars appear...
        spt.setVisible( true );
    }
    // Inner class used to display the image...
    private class ImageCanvas extends Canvas
    {
        private Image im;
        private ImageCanvas( Image i )
        {
            im = i;
        }
        public void paint( Graphics g )
        {
            g.drawImage( im, 0, 0, this );
        }
        public Dimension getPreferredSize()
        {
            int w = im.getWidth( ScrollPaneTest.this );
            int h = im.getHeight( ScrollPaneTest.this );
            System.out.println( "" + w + " " + h );
            return new Dimension( w, h );
        }
    }
}

HTH,
-Nate