- GridBagConstraints specifies how to display a specific component.
- Every component added to a GridBagLayout container should have a GridBagConstraints object associated with it.
- Without GridBagConstraints, the GridBagLayout is a blank slate.
import java.awt.Component;
import java.awt.Container;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import javax.swing.JButton;
import javax.swing.JFrame;
public class GridBagButtons {
private static final Insets insets = new Insets(0, 0, 0, 0);
public static void main(final String args[]) {
final JFrame frame = new JFrame("GridBagLayout");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new GridBagLayout());
JButton button;
// Row One - Three Buttons
button = new JButton("One");
addComponent(frame, button, 0, 0, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);
button = new JButton("Two");
addComponent(frame, button, 1, 0, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);
button = new JButton("Three");
addComponent(frame, button, 2, 0, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);
// Row Two - Two Buttons
button = new JButton("Four");
addComponent(frame, button, 0, 1, 2, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);
button = new JButton("Five");
addComponent(frame, button, 2, 1, 1, 2, GridBagConstraints.CENTER, GridBagConstraints.BOTH);
// Row Three - Two Buttons
button = new JButton("Six");
addComponent(frame, button, 0, 2, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);
button = new JButton("Seven");
addComponent(frame, button, 1, 2, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);
frame.setSize(500, 200);
frame.setVisible(true);
}
private static void addComponent(Container container, Component component, int gridx, int gridy,
int gridwidth, int gridheight, int anchor, int fill) {
GridBagConstraints gbc = new GridBagConstraints(gridx, gridy, gridwidth, gridheight, 1.0, 1.0,
anchor, fill, insets, 0, 0);
container.add(component, gbc);
}
}
