Need help with Threading GUI progress bar

Question

Anyone able to help? I'm sure you've seen this a million times. I've google'd around and tried examples but still can't get a progress bar to work properly under the following situation:
1. Created a panel with several components to select directory, display directory in tree etc.
2. When a specific button (Search) is clicked, I want a secondary window to popup and report progress of searching down the directory.
As you'll probably guess, the progress window isn't being updated until the end. I'm using Threads and using InvokeLater but nothing happens. Is there any good example that does the above? I can't seem to find one to figure this out.
Thanks
Speedy.
Sample code:
main.java:
========
public class Main {
public static void main(String[] args) {
MainPanel mainPanel = new MainPanel();
mainPanel.show();
MainPanel.java:
============
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
public class MainPanel extends JFrame implements ActionListener {
public MainPanel() {
this.setSize(100,100);
JButton startButton = new JButton("Start");
this.getContentPane().add(startButton);
startButton.addActionListener(this);
public void actionPerformed(ActionEvent event) {
ProgressPanel pp = new ProgressPanel();
pp.show();
SimpleTask st = new SimpleTask(pp);
st.start();
while (st.isAlive()) {
System.err.println("waiting..");
try {
Thread.sleep(100);
} catch (Exception e) {};
System.err.println("finished!");
SimpleTask.java:
=============
import javax.swing.SwingUtilities;
public class SimpleTask extends Thread {
ProgressPanel pp = null;
public SimpleTask(ProgressPanel _pp) {
pp = _pp;
this.setDaemon(true);
int i = 0;
String position = "";
public void run() {
Runnable updateGUI = new Runnable() {
public void run() {
pp.setText(position);
try {
for (i=0; i<50; i++) {
position = "Now on = " + new Integer(i).toString();
System.err.println(position);
SwingUtilities.invokeLater(updateGUI);
sleep(100);
} catch (Exception e) {}
ProgressPanel.java:
===============
import javax.swing.JFrame;
import javax.swing.JLabel;
public class ProgressPanel extends JFrame {
private JLabel label = new JLabel();
public ProgressPanel() {
this.setSize(200,200);
this.setLocation(100,100);
this.getContentPane().add(label);
setText("Start");
public void setText(String text) {
label.setText(text);
}

Answer 1

Ok, I'll look down that road. I should have said the Thread is being used because the current while loop will be changed to perform real work. Just an example at the moment to show what I'm trying to do. Does this make a difference? The real task will be to drill down directories, counting file types/dirs etc...