Progress bar to run simultaneously with a function(in another class)

Question

I have created a form on which two components are present, button and progressbar (Netbeans drag and drop).Form contains the main method from where my application starts.I have created another class as well in which i have written a function.What i want is that when i press a button the application goes into the function and the progressbar runs simultaneously with it and when that function is complete with its functionality the the progress bar shows 100% complete.Now this function can take anytime for its completion so i cannot set the max value for the progressbar.So, what to do in this case?Can anyone please provide me with a good example .

Answer 1

JProgressBar.setIndeterminate(true)

Answer 2

Since what sort of a work you are doing inside that so called "Called Function", so it's tough to say, what you want in the scenario, though you can put your lines like progressBar.setValue(someProgress); at regular intervals with it's Indeterminate State to true, and at the end of the function you can simply say that progressBar.setValue(100); and the Indeterminate State will turn to false here, so that it can show that to the end user.

Have a look at this sample program :

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class ProgressExample
{
    public static JProgressBar progressBar;

    private void createAndDisplayGUI()
    {
        JFrame frame = new JFrame("Progress Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationByPlatform(true);

        JPanel contentPane = new JPanel();
        contentPane.setLayout(new BorderLayout(5, 5));

        progressBar = new JProgressBar(0, 100);
        progressBar.setValue(0);                

        JButton button = new JButton("START");
        button.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent ae)
            {
                progressBar.setIndeterminate(true);
                WorkingDialog wd = new WorkingDialog();
                wd.createAndDisplayDialog();
            }
        });

        contentPane.add(progressBar, BorderLayout.PAGE_START);
        contentPane.add(button, BorderLayout.PAGE_END);

        frame.setContentPane(contentPane);
        frame.pack();
        frame.setVisible(true);
    }   

    public static void main(String... args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                new ProgressExample().createAndDisplayGUI();
            }
        });
    }
}

class WorkingDialog extends JDialog
{
    private String message = "HelloWorld";
    private int count = 0;
    private JTextField tfield;
    private Timer timer;

    private ActionListener timerAction = new ActionListener()
    {
        public void actionPerformed(ActionEvent ae)
        {
            if (count == 10)
            {
                timer.stop();
                ProgressExample.progressBar.setIndeterminate(false);
                ProgressExample.progressBar.setValue(100);
                ProgressExample.progressBar.setStringPainted(true);
                dispose();
                return;
            }
            tfield.setText(tfield.getText() + message.charAt(count));
            count++;
        }
    };

    public void createAndDisplayDialog()
    {
        setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
        setLocationByPlatform(true);

        JPanel panel = new JPanel();
        tfield = new JTextField(10);

        panel.add(tfield);

        add(panel);
        pack();
        setVisible(true);

        timer = new Timer(1000, timerAction);
        timer.start();
    }
}

So , it seems like you are write

ProgressExample.progressBar.setIndeterminate(false);
ProgressExample.progressBar.setValue(100);
ProgressExample.progressBar.setStringPainted(true);

after your while loop.

Answer 3

You can take a look at my answer in a previous SO question, which contains a sample using a JProgressBar which gets updates from another Thread by using a SwingWorker. Whether or not to use a SwingWorker depends a bit on your use case. If the function take some time to run you better use the SwingWorker to avoid blocking the UI.