JProgressBar - Please Help

[Ronnie Coh]

I have seen several examples of a JProgress bar and file transphers, but I need a JProgressBar to show the time it takes to process something.

Does anyone have an example where the a programming is calculating information and the a JProgressBar is being displayed?

Do I need to use a Thread and how would I do it?
Thanks - Ronnie

[Aaron Roberts]

Are you looking for a progress bar that is really showing the time left or maybe how long something has taken already?

It would be pretty easy to start a timer and have it call a method which updates your display. Timers run on the event dispatch thread, so updating your GUI would be safe.

Does this help?

Regards,
Aaron R>

[Ronnie Coh]

I have a program that seems to takes a long time to process/calculate information. In stead of having a blank screen I wanted the user to understand that the program is working.

[Craig Wood]

If you can get something like a file size in you heavy–process method you can use the determinate mode in the JProgressBar.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
 
public class ProgressPossibility
{
    static final int
        DETERMINATE   = 0,
        INDETERMINATE = 1;
    static int progressMode = 0;
 
    public static void main(String[] args)
    {
        JButton start = new JButton("calculate");
        start.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                final JProgressBar progressBar = new JProgressBar(0, 100);
                final JDialog dialog = new JDialog(new Frame(),
                                                   "calculation in progress");
                new Thread(new Runnable()
                {
                    public void run()
                    {
                        beginCalculation(progressBar, dialog);
                    }
                }).start();
                showDialog(progressBar, dialog);
            }
        });
        String[] ids = { "determinate", "indeterminate" };
        final JRadioButton[] buttons = new JRadioButton[ids.length];
        ButtonGroup group = new ButtonGroup();
        ActionListener l = new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                JRadioButton button = (JRadioButton)e.getSource();
                for(int j = 0; j < buttons.length; j++)
                    if(button == buttons[j])
                        progressMode = j;
            }
        };
        JPanel south = new JPanel();
        for(int j = 0; j < buttons.length; j++)
        {
            buttons[j] = new JRadioButton(ids[j]);
            group.add(buttons[j]);
            buttons[j].addActionListener(l);
            south.add(buttons[j]);
        }
        buttons[0].setSelected(true);
        JPanel north = new JPanel();
        north.add(start);
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(north, "North");
        f.getContentPane().add(south, "South");
        f.setSize(300,175);
        f.setLocation(200,200);
        f.setVisible(true);
    }
 
    private static void beginCalculation(JProgressBar progressBar, JDialog dialog)
    {
        int total = 5000;
        int current = 0;
        while(current < total)
        {
            try
            {
                Thread.sleep(500);
                current += 500;
            }
            catch(InterruptedException ie)
            {
                System.out.println("interrupt: " + ie.getMessage());
                dialog.dispose();
                break;
            }
            int value = (current * 100)/total;
            progressBar.setValue(value);
            if(current == total)
                dialog.dispose();
        }
    }
 
    private static void showDialog(JProgressBar progressBar, JDialog dialog)
    {
        progressBar.setStringPainted(true);
        if(progressMode == INDETERMINATE)
        {
            progressBar.setIndeterminate(true);
            progressBar.setString("calculating . . .");
        }
        else
            progressBar.setIndeterminate(false);
        JPanel panel = new JPanel();
        panel.add(progressBar);
        dialog.getContentPane().add(panel);
        dialog.setSize(260,100);
        dialog.setLocation(270,350);
        dialog.setVisible(true);
    }
}