JDialog has transparent background, not contents

With the code below, the dialog box does not display the progress bar.
The interior of the dialog box is transparent (showing as grey in the attached image).
How do I get the progress bar to appear?

I've noticed the if I call:
progressDialog.setModal(true);
then the progress is displayed, but then you have to click on the X to get the dialog box to not display,
setVisible(false) has no effect.
final JProgressBar jProgressBar = new JProgressBar(0, 100);
jProgressBar.setIndeterminate(true);
JDialog progressDialog = createDialog( "Analyzing ..." );
progressDialog.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
progressDialog.getContentPane().add(jProgressBar);
progressDialog.setSize(300, 100);
progressDialog.setVisible(true);
  
  <do stuff>

progressDialog.setVisible(false);

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analyzing.png
LVL 1
allelopathAsked:
Who is Participating?
 
gordon_vt02Connect With a Mentor Commented:
Are you running the task in the main Swing thread or in a background thread?  If you're running it in the main Swing thread, it may not allow the progress bar to update itself because its taking all the processing time.  You should move your progress task into its own thread, but make sure you only update the progress bar in the Swing EventDispatcher thread.

Since you are using an indeterminate progress bar, you won't need to worry about updating it, but you should still run your working code in a background thread and have it stop the progress bar (on the EventDispatch thread) when it completes.
final JProgressBar progressBar = new JProgressBar();
// init progress bar and dialog
new Thread(new Runnable() {
    public void run() {
        // do some unit of work
        
        // ensure progress bar updates happen on
        // the event dispatch thread
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                progressBar.setValue(value);
            }
        });
    }
}).start();

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for_yanCommented:
Can you post the whole code, so that I could compile and run it myself?
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allelopathAuthor Commented:
Unfortunately, no, it is within a much larger chunk of code.
Can you theorize what setModal(true) might be doing to make it display?
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for_yanConnect With a Mentor Commented:
Maybe it has something to do with the threads.
This is the code from

http://www.java2s.com/Code/Java/Swing-JFC/Creatingamodalprogressdialog.htm

which I modified - and it runs both when it is modal or not modal
and I added the button which can stop or close it.
Compare it with your code, maybe it will help

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.*;

public class Main implements ActionListener {
    JButton jb;

    Thread t;
    JDialog dlg;
    boolean stop;
  public static void main(String[] args) {
      new Main();
  }

      public Main(){
    JFrame parentFrame = new JFrame();
    parentFrame.setSize(500, 150);
    JLabel jl = new JLabel();
    jb = new JButton("stop");

      jb.addActionListener(this);

    
    jl.setText("Count : 0");

    parentFrame.add(BorderLayout.CENTER, jl);
           parentFrame.add(BorderLayout.EAST, jb);
           

    parentFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    parentFrame.setVisible(true);

     dlg = new JDialog(parentFrame, "Progress Dialog", false);
    JProgressBar dpb = new JProgressBar(0, 500);
    dlg.add(BorderLayout.CENTER, dpb);
    dlg.add(BorderLayout.NORTH, new JLabel("Progress..."));
    dlg.setDefaultCloseOperation(JDialog.DO_NOTHING_ON_CLOSE);
    dlg.setSize(300, 75);
    dlg.setLocationRelativeTo(parentFrame);

    t = new Thread(new Runnable() {
      public void run() {
        dlg.setVisible(true);
      }
    });
    t.start();
    for (int i = 0; i <= 500; i++) {
      jl.setText("Count : " + i);
      dpb.setValue(i);
      if(dpb.getValue() == 500 || stop){
       // dlg.setVisible(false);
       // System.exit(0);
          break;

      }
      try {
        Thread.sleep(25);
      } catch (InterruptedException e) {
        e.printStackTrace();
      }
    }
    dlg.setVisible(true);
  }

    public void actionPerformed(ActionEvent e){
        if(e.getSource().equals(jb)){
            stop = true;
               dlg.setVisible(false);
        }

    }

  }

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allelopathAuthor Commented:
You are both correct in that it is a threading issue. I modified for_yan's code to be closer to what I have (attached). Standalone, this works fine. However, when I incorporate this into my code, the same problem occurs (progress bar does not show). This is because, as gordon_vt02 shows, the work itself must also be in the thread. gordon_vt02's code is not quite right either, however. He shows:
- do the work
- invokeLater

When what it needs to be is:
- invokeLater
- do the work
- progressDialog.setVisible(false)
 
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allelopathAuthor Commented:

import java.awt.BorderLayout;

import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JProgressBar;

public class ProgressIndeterminateThread {

	Thread thread;
	JDialog jDialog;

	/**
	 * constructor
	 */
	public ProgressIndeterminateThread(){
		
		final int COUNT = 250;
		
		JFrame parentFrame = new JFrame();
		parentFrame.setSize(500, 150);
		JLabel jLabel = new JLabel();

		jLabel.setText("Count : 0");

		parentFrame.add(BorderLayout.CENTER, jLabel);
		parentFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		parentFrame.setVisible(true);

		jDialog = new JDialog(parentFrame, "Progress Dialog", false);
		JProgressBar jProgressBar = new JProgressBar(0, COUNT);
	    jProgressBar.setIndeterminate(true);
		jDialog.add(BorderLayout.CENTER, jProgressBar);
		jDialog.setDefaultCloseOperation(JDialog.DO_NOTHING_ON_CLOSE);
		jDialog.setSize(300, 75);
		jDialog.setLocationRelativeTo(parentFrame);

		thread = new Thread(new Runnable() {
			public void run() {
				jDialog.setVisible(true);
			}
		});
		thread.start();
		
		// do stuff
		for (int i = 0; i <= COUNT; i++) {
			
			jLabel.setText("Count : " + i);
			jProgressBar.setValue(i);
			// when done doing stuff, get out
			if (i == COUNT) {
				break;
			}
			
			// slow the count down
			try {
				Thread.sleep(10);
			} 
			catch (InterruptedException e) {
				e.printStackTrace();
			}
		} // end for do stuff

		jDialog.setVisible(false);

		//parentFrame.setVisible(false);
	}

	/**
	 * 
	 * @param args
	 */
	public static void main(String[] args) {
		new ProgressIndeterminateThread();
	}
}

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