How to measure progress of task for JProgressBar in java

Question

I have developed a UI in which i am taking the shared folder location of a zipped file copying the files contained in that to my system. Performing some operations on that and again storing that to a machine location, all this things are done using UI. For this now i want to use the JProgressBar but i am not understanding how with the help of thread i will measure the progress. I saw the tutorial for JProgressBar but that didn't helped.

Code which i have written:

 import java.awt.Toolkit;
 import java.awt.event.*;
 import javax.swing.*;
 import java.beans.*;
 import java.util.Random;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 public class ProgressBar extends javax.swing.JFrame {
/**
 * Creates new form ProgressBar
 */


public ProgressBar() {

    initComponents();

}

/**
 * This method is called from within the constructor to initialize the form.
 * WARNING: Do NOT modify this code. The content of this method is always
 * regenerated by the Form Editor.
 */
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">                          
private void initComponents() {

    jButton1 = new javax.swing.JButton();
    jProgressBar1 = new javax.swing.JProgressBar();
    jTextField1 = new javax.swing.JTextField();
    jScrollPane1 = new javax.swing.JScrollPane();
    jTextArea1 = new javax.swing.JTextArea();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    jButton1.setText("ok");
    jButton1.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton1ActionPerformed(evt);
        }
    });

    jProgressBar1.setStringPainted(true);

    jTextArea1.setColumns(20);
    jTextArea1.setRows(5);
    jScrollPane1.setViewportView(jTextArea1);

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(layout.createSequentialGroup()
                    .addGap(68, 68, 68)
                    .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, 119, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addGap(44, 44, 44)
                    .addComponent(jButton1))
                .addGroup(layout.createSequentialGroup()
                    .addGap(150, 150, 150)
                    .addComponent(jProgressBar1, javax.swing.GroupLayout.PREFERRED_SIZE, 167, javax.swing.GroupLayout.PREFERRED_SIZE)))
            .addContainerGap(298, Short.MAX_VALUE))
        .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
            .addGap(0, 0, Short.MAX_VALUE)
            .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(99, 99, 99))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGap(41, 41, 41)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jButton1)
                .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addGap(46, 46, 46)
            .addComponent(jProgressBar1, javax.swing.GroupLayout.PREFERRED_SIZE, 27, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(48, 48, 48)
            .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(91, Short.MAX_VALUE))
    );

    pack();
}// </editor-fold>                        

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    // TODO add your handling code here:

    iterate();

}                                        

/**
 * @param args the command line arguments
 */
public static void main(String args[]) {
    /* Set the Nimbus look and feel */
    //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
    /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
     * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
     */
    try {
        for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
            if ("Nimbus".equals(info.getName())) {
                javax.swing.UIManager.setLookAndFeel(info.getClassName());
                break;
            }
        }
    } catch (ClassNotFoundException ex) {
        java.util.logging.Logger.getLogger(ProgressBar.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (InstantiationException ex) {
        java.util.logging.Logger.getLogger(ProgressBar.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (IllegalAccessException ex) {
        java.util.logging.Logger.getLogger(ProgressBar.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (javax.swing.UnsupportedLookAndFeelException ex) {
        java.util.logging.Logger.getLogger(ProgressBar.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }
    //</editor-fold>

    /* Create and display the form */
    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            new ProgressBar().setVisible(true);

    });
}

public void iterate()
    {
        int i = 0;
        while(i<=100){    
        jProgressBar1.setValue(i);    
        i=i+15;  

        try{Thread.sleep(700);}catch(Exception e){}    
    }    
  }

// Variables declaration - do not modify                     
private javax.swing.JButton jButton1;
private javax.swing.JProgressBar jProgressBar1;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JTextArea jTextArea1;
private javax.swing.JTextField jTextField1;
// End of variables declaration                   
}

I'd start by using a `SwingWorker`, [for example](http://stackoverflow.com/questions/24835638/issues-with-swingworker-and-jprogressbar/24835935#24835935). The problem will be trying to determine the amount of work you need to do — MadProgrammer, Feb 28 '17 at 05:13

score 3 · Accepted Answer · edited Jun 20 '20 at 09:12

The key point is that you first define a value that can be measured to report your progress against.

Example: you give like 15, 20 points/percent to each of the steps listed above, and each time such a step is completed, you increase your progress. (you can try to measure execution times upfront, to give different "weights" to the different steps; or you simply make each step contribute the same "amount" to reach "100%" in the end).

For the mechanics how to that, that is for sure described in that tutorial!

One key aspect here is threading. In your example, your main thread calls setValue() on the progress bar. That will not work. When you turn back to the oracle tutorial you find there:

Task is a subclass of javax.swing.SwingWorker. The Task instance does three important things for ProgressBarDemo:

The instance invokes the doInBackground in a separate thread. This is where the long-running task is actually executed. Using a background thread instead of the event-dispatching thread prevents the user interface from freezing while the task is running.

When the background task is complete, the instance invokes the done method in the event-dispatching thread.

The instance maintains a bound property, progress, that is updated to indicate the progress of the task. The propertyChange method is invoked each time progress changes.

check i have written an iterate method which will change the value of jProgressBar. But in output it directly shows jProgressBar at end. It is not moving from 15% to 30%. Whats wrong in this ? — Srishti, Feb 28 '17 at 07:02
See my updates ... the point is: yes, this is complicated stuff. That means: you don't just read it once and copy&paste only those parts you understand. You keep reading and iterating the **whole** thing until you get it. Hope this helps ... — GhostCat, Feb 28 '17 at 07:13

score -1 · Answer 2 · answered Feb 28 '17 at 05:47

-1

Easy. Have a look at ProgressMonitorInputStream.

answered Feb 28 '17 at 05:47

user207421

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How to measure progress of task for JProgressBar in java

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