Re: Coordinating multiple JTextField updates across panels

"Jarrick Chagma" <>
Tue, 16 Jun 2009 10:33:22 +1000
"markspace" <> wrote in message

Jarrick Chagma wrote:

Is each field in a separate panel? Are there more than 50 panels on the
screen at once? Separate panels and their abundance are the keys.

I put 100 JTextFields each in it's own panel, plus some more panels and
containers for formatting, and I don't see any slowness. You might, and
maybe your needs are more sensitive than what I did, but this seems to
update fine for me.

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 * and open the template in the editor.

package fubar;

import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.LayoutManager;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;

 * @author Brenden
public class UpdateTest {

    private static final int ROWS = 20;
    private static final int COLS = 5;

    private final List<JTextField> textFieldList =
            new ArrayList<JTextField>( ROWS * COLS );

    public static void main(String[] args) {

        SwingUtilities.invokeLater( new Runnable() {
            public void run() {
                new UpdateTest().createAndShowGui();
        } );

    private void createAndShowGui() {
        JFrame jframe = new JFrame("Update Test");
        Box centralContent = new Box( BoxLayout.PAGE_AXIS );
        for( int rows = 0; rows < ROWS; rows++ ) {
            JPanel rowPanel = new JPanel();
            for( int cols = 0; cols < COLS; cols ++ ) {
                JTextField textField = new JTextField( 10 );
                textFieldList.add( textField );
                rowPanel.add( new JPanel().add( textField ) );
            centralContent.add( rowPanel );
        jframe.add( centralContent );
        JButton jbut = new JButton( "Update Now" );
        jbut.addActionListener( new UpdateListener() );
        JPanel bottom = new JPanel();
        LayoutManager layout = new FlowLayout( FlowLayout.CENTER );
        bottom.add( jbut );
        jframe.add( bottom, BorderLayout.SOUTH );
        jframe.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
        jframe.setLocationRelativeTo( null );
        jframe.setVisible( true );

    private class UpdateListener implements ActionListener {
        private int count = 1;
        public void actionPerformed(ActionEvent e) {
            String update = "Update" + count;
            for (JTextField t : textFieldList ) {
                t.setText( update );

I don't know, I am not doing anything particularly special but I see a
noticeable effect when multiple fields are updated simultaneously in
multiple panels. Perhaps it's my machine because I also notice a
considerable delay when restoring Swing applications that have been
minimised (as reported earlier) and nobody else seems to have that problem



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