Java Swing How to - Do the time consuming task in a Thread and update JProgressBar with SwingUtilities

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Question

We would like to know how to do the time consuming task in a Thread and update JProgressBar with SwingUtilities.

Answer

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
/*from w  w  w .jav a 2s.c o  m*/
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JProgressBar;
import javax.swing.SwingUtilities;

public class Main extends JFrame {
  int minValue = 0;
  int maxValue = 100;
  int counter = 0;
  JProgressBar progressBar = new JProgressBar();

  public Main() {
    super();
    setSize(300, 100);

    progressBar.setMinimum(minValue);
    progressBar.setMaximum(maxValue);
    progressBar.setStringPainted(true);
    JButton start = new JButton("Start");

    start.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        Thread runner = new Thread() {
          public void run() {
            counter = minValue;
            while (counter <= maxValue) {
              Runnable runme = new Runnable() {
                public void run() {
                  progressBar.setValue(counter);
                }
              };

              SwingUtilities.invokeLater(runme);
              counter++;
              try {
                Thread.sleep(100);
              } catch (Exception ex) {
              }
            }
          }
        };
        runner.start();
      }
    });

    getContentPane().add(progressBar, BorderLayout.CENTER);
    getContentPane().add(start, BorderLayout.WEST);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setVisible(true);
  }

  public static void main(String[] args) {
    new Main();
  }
}

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