JProgressBar within the progress of a JProgressBar

Question

Hello,
I'm looking to make a progress bar within the progress of another progress bar, is this possible? That is to say, I want to have a container that fills up to some level, then the "stuff" that filled it up itself fills with something else to another level. Right now I'm just drawing a box, then a somewhat shorter box within the first box, but I thought it might be neater with a JProgressBar or something like it. How would I go about using or extending JProgressBar to accomplish this effect.
Thank you.

Answer 1

Here's sort of a proof of concept. JProgressBar is a container, so you can add any component you want to it including another JProgressBar. Using GridBagLayout I made the smaller JProgressBar centered within the larger one. The smaller one also occupies 40% the width and 20% the height of the larger one. So if the larger one gets bigger (or smaller), the smaller progress bar will scale accordingly. The SwingWorker does my long task.
import javax.swing.*;
import java.util.List;
import java.util.Random;
import java.awt.GridBagLayout;
import java.awt.GridBagConstraints;
public class ProgressBarTest {
    public static void main(String[] args) {
       SwingUtilities.invokeLater(new Runnable() {
           public void run() {
               createAndShowGUI();
    private static void createAndShowGUI() {
        final JProgressBar outer = new JProgressBar();
        final JProgressBar inner = new JProgressBar();
        GridBagLayout layout = new GridBagLayout();
        outer.setLayout(layout);
        outer.add(new JLabel(),createConstraints(0, 0, 3, 1, 1.0, .4));
        outer.add(new JLabel(),createConstraints(0, 1, 1, 1, .30, .2));
        inner.setBorder(null);
        inner.setPreferredSize(new java.awt.Dimension());
        outer.add(inner, createConstraints(1, 1, 1, 1, .4, .2));
        outer.add(new JLabel(),createConstraints(2, 1, 1, 1, .30, .2));
        outer.add(new JLabel(),createConstraints(0, 2, 3, 1, 1.0, .4));
        SwingWorker worker = new SwingWorker<Void,Object>() {
            Random rn = new Random();
            @Override
            protected Void doInBackground() throws Exception {
                for(int i = 0; i < 100; i++) {
                    publish(outer,i);
                    for(int j = 0; j < 100; j += rn.nextInt(12)) {
                        publish(inner,j);
                        try{
                            Thread.sleep(10);
                        }catch(InterruptedException e) {
                            return null;
                return null;
            @Override
            protected void process(List<Object> chunks) {
                JProgressBar progressBar = (JProgressBar) chunks.get(0);
                int value = (Integer) chunks.get(1);
                progressBar.setValue(value);
            @Override
            protected void done() {
                outer.setValue(100);
                outer.removeAll();
        JFrame frame = new JFrame();
        frame.setContentPane(outer);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
        worker.execute();
    private static GridBagConstraints createConstraints(
            int gridX, int gridY, int gridW, int gridH,
            double weightX, double weightY) {
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.gridx = gridX; gbc.gridy = gridY;
        gbc.gridwidth = gridW; gbc.gridheight = gridH;
        gbc.weightx = weightX; gbc.weighty = weightY;
        gbc.fill = GridBagConstraints.BOTH;
        return gbc;
}