Sizing a JPanel on its contents

Question

Hi everybody,
Does anyone know of a way to resize a JPanel around its contents? I have a panel that will be filled with 3, 5, or 7 lines of text, depending on a button click, and I'd like the panel to size appropriately on the button click. Is there a way to do this? I already have working code, working buttons, working lines, everything, but I just don't know how to do the resizing on demand. If anyone could point me in the right direction, I'd appreciate it.
Thanks,
Jezzica85

Answer 1

Thanks Darryl,
It looks like you posted just ahead of me, I was whipping up a SSCCE. For some reason, revalidate() isn't doing the job; it's probably something weird I'm doing, maybe this will help :
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class ResizeTest extends JPanel {
    private int entries;
    private static final long serialVersionUID = 5290537936355330083L;
    public ResizeTest( int number ) {
        entries = number;
        create();
    public void changeEntries( int entries ) {
        this.entries = entries;
        removeAll();
        create();
        revalidate();
        repaint();
    private void create() {
        setLayout( new GridLayout( entries, 1 ) );
        for( int i = 0; i < entries; i++ ) { add( new JLabel( "Line" ) ); }
        revalidate();
    // testing
    public static void main( String args[] ) {
        final ResizeTest panel = new ResizeTest(5);
        JPanel buttonPanel = new JPanel( new GridLayout( 1, 7 ) );
        for( int i = 3; i <= 15; i+=2 ) {
            JButton button = new JButton( "Change to " + i );
            final int blah = i;
            button.addActionListener( new ActionListener() {
                public void actionPerformed( ActionEvent e ) {
                    panel.changeEntries( blah );
            buttonPanel.add( button );
        JFrame frame = new JFrame();
        frame.setLayout( new BorderLayout() );
        frame.add( panel );
        frame.add( buttonPanel, BorderLayout.SOUTH );
        frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
        frame.pack();
        frame.setLocationRelativeTo( null );
        frame.setVisible( true );
}Thanks,
Jezzica85