Unable to change the text of a JLabel

Question

hi!
i have created a JLabel and add it to my frame. Now, when the user clicks the button on the frame, i changed the test of the label and after that some really heavy processing takes place. and till that processing completes, the changed text does not get display. is it because that the repaint has very low priority? my requirement is that the text shuld get updated immediately.
Any ideas?
regards
Deepak Saini

Answer 1

I usually suggest to use:
component.paintImmediately(component.getVisibleRect());
Wondering what the difference between 'paintImmediately()' and 'update()' was, I created a simple test program. The program simply changed the text in a JTextField 1000 times.
Here is what I found:
1) paintImmediately was 10-20% faster
2) paintImmediately produced no flicker
I changed my program to use a JLabel instead of a JTextField and found:
1) update() did not work
Here is my sample program in case you are interested.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
import javax.swing.text.*;
public class StatusBar extends JFrame
     JTextField statusBar;
public StatusBar()
JPanel panel = new JPanel();
panel.setLayout( new BorderLayout() );
     setContentPane( panel );
          JButton button = new JButton( "Connect..." );
          panel.add( button, BorderLayout.NORTH );
          button.addActionListener( new ActionListener()
               public void actionPerformed(ActionEvent e)
     long t1 = System.currentTimeMillis();
                    for (int i = 0; i < 1000; i++)
                         statusBar.setText( "label " + i );
//                         statusBar.paintImmediately(statusBar.getVisibleRect());
                         statusBar.update(statusBar.getGraphics());
                    System.out.println( (System.currentTimeMillis() - t1) );
          statusBar = new JTextField("No Connection");
          panel.add( statusBar, BorderLayout.SOUTH );
public static void main(String[] args)
StatusBar frame = new StatusBar();
frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
frame.pack();
frame.setVisible(true);