Build a progress bar without launching a new Thread

Question

I need to add a progress bar in a JFrame but I want to update this bar without generating a new Thread (for example SwingWorker that update bar in background).

Answer 1

You should use Modal Dialog for blocking:

EDIT: progress visualization in EDT - that can also be done with your PropertyChangeEvent

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

import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JProgressBar;
import javax.swing.SwingUtilities;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

public class Test {

    public Test() {
        createAndShowGUI();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new Test();
            }
        });
    }

    private void createAndShowGUI() {
        JFrame frame = new JFrame();
        frame.setSize( 500, 500 );
        frame.setLocationRelativeTo( null );
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout( new BorderLayout() );
        frame.getContentPane().add(new JButton( openChooseGUI() ), BorderLayout.SOUTH);      
        frame.setVisible(true);
    }

    private Action openChooseGUI() {
        return new AbstractAction("ChooseGUI") {
            @Override
            public void actionPerformed( ActionEvent e ) {
                new ChooseGUI().setVisible( true );
            }
        };
    }

    public class ChooseGUI extends JFrame {

        public ChooseGUI() {
            setSize( 200, 200 );
            setLocationRelativeTo( null );
            setDefaultCloseOperation( JFrame.DISPOSE_ON_CLOSE );
            getContentPane().setLayout( new BorderLayout() );
            getContentPane().add( new JLabel( "This is ChooseGUI" ), BorderLayout.CENTER );
            init();
        }

        private void init() {
            final JDialog progressDialog = new JDialog( this, true );
            final JProgressBar progress = new JProgressBar( JProgressBar.HORIZONTAL );
            progress.addChangeListener( new ChangeListener() {
                @Override
                public void stateChanged( ChangeEvent e ) {
                    // TODO Auto-generated method stub
                    int current = ((JProgressBar)e.getSource()).getValue();
                    if(current >= 100) {
                        progressDialog.dispose();
                    }
                }
            } );

            progressDialog.setSize( 400, 100 );
            progressDialog.setLocationRelativeTo( this );
            progressDialog.getContentPane().setLayout( new BorderLayout() );
            progressDialog.getContentPane().add( progress, BorderLayout.NORTH );
            progressDialog.getContentPane().add(  new JLabel( "This is Progress Dialog" ), BorderLayout.CENTER );
            progressDialog.getContentPane().add(  new JButton(new AbstractAction("click to progress") {
                @Override
                public void actionPerformed( ActionEvent e ) {
                    progress.setValue( progress.getValue()+25 );
                }
            }), BorderLayout.SOUTH );
            progressDialog.setVisible( true );
        }

    }

}