Reviews : Java Books :
Professional Java Programming : Using Layout Managers

gridwidth

This constraint identifies the number of columns that the component spans, and its default value is 1. For example, in the screenshot below, the button in the third row spans both columns:

The code to create this display is as follows:

import java.awt.*;
import javax.swing.*;

public class ColumnSpan {

  public static void main(String[] args) {
    JFrame f = new JFrame();
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Container pane = f.getContentPane();
    pane.setLayout(new GridBagLayout());
    GridBagConstraints gbc = new GridBagConstraints();
    gbc.gridx = 1;
    gbc.gridy = GridBagConstraints.RELATIVE;
    pane.add(new JButton("First row, first column"), gbc);
    pane.add(new JButton("Second row"), gbc);
    gbc.gridwidth = 2;
    pane.add(new JButton("Third row, spans two columns"), gbc);
    gbc.gridwidth = 1;
    gbc.gridx = GridBagConstraints.RELATIVE;
    pane.add(new JButton("First row, second column"), gbc);
    f.setSize(400, 300);
    f.setVisible(true);
  }

}

In this case, the button's size is set to its preferred width, and the button is centered horizontally within its display area. However, it can be made to fill both columns by setting the fill value:

import java.awt.*;
import javax.swing.*;

public class ColumnSpan {

  public static void main(String[] args) {
    JFrame f = new JFrame();
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Container pane = f.getContentPane();
    pane.setLayout(new GridBagLayout());
    GridBagConstraints gbc = new GridBagConstraints();
    gbc.gridx = 1;
    gbc.gridy = GridBagConstraints.RELATIVE;
    pane.add(new JButton("First row, first column"), gbc);
    pane.add(new JButton("Second row"), gbc);
    gbc.gridwidth = 2;
    gbc.fill = GridBagConstraints.HORIZONTAL;
    pane.add(new JButton("Third row, spans two columns"), gbc);
    gbc.gridwidth = 1;
    gbc.fill = GridBagConstraints.NONE;
    gbc.gridx = GridBagConstraints.RELATIVE;
    pane.add(new JButton("First row, second column"), gbc);
    f.setSize(400, 300);
    f.setVisible(true);
  }

}

With these alterations, the second being to reset the fill value, the display now becomes:

How to Add Java Applets to Your Site

New on the Java Boutique:

New Review:

Time Management Made Easy with the Quartz Enterprise Job Scheduler
Why not just use the Java timer API? This open source scheduling API boasts simplicity, ease-of-integration, a well-rounded feature set, and it's free!

New Applet:

Reverse Complement
Reverse Complement is a simple applet that converts DNA or RNA sequences into three useful formats.

Elsewhere on internet.com:

WebDeveloper Java
Lots of Java information on webdeveloper.com

WDVL Java
Thorough Java resource at the Web Developer's Virtual Library.

ScriptSearch Java
Hundreds of free Java code files to download.

jGuru: Your View of the Java Universe
Customizable portal with online training, FAQs, regular news updates, and tutorials.