Java Swing GridBagLayout

GridBagLayout extends the capabilities of the GridLayout. Like GridLayout, GridBagLayout places component in each individual cell in a grid. In addition, GridBagLayout also allows the component to span to multiple columns or rows. In order to do so, GridBagConstraints is used for each component.

In order to use GridBagLayout, first, you need to create a GridBagConstraints object and fill appropriate properties. Then you can add a component to a container using this GridBagConstraints object.

The following is the typical code snippet to use GridBagConstraints along with GridBagLayout:

JPanel panel = new JPanel(new GridBagLayout());
GridBagConstraints cst = new GridBagConstraints();
// fill properties of GridBagConstraints...
// ...
panel.add(component,c);Code language: JavaScript (javascript)

Here are properties of GridBagConstraints and their descriptions:

Properties	Description
gridx,gridy	Specify the row and column from top to bottom and from left to right starting from zero. For example gridx = 0, gridy = 0 is the top left cell of the grid.
gridwidth, gridheight	Specify number of rows (gridheight) and columns (gridwidth) to which a component can span. The default value of gridwidth and gridheight is 1.
fill	This property is used to resolve whether and how to resize the component when the component’s display region is larger than the component’s requested size. The values for fill property are: NONE, VERTICAL, HORIZONTAL, VERTICAL and BOTH.
ipadx, ipady	The ipadx, ipady property are used to set the internal padding of the component.
insets	The insets property is used to set the external padding of the component.
weightx, weighty	These properties are used to specify how to distribute space between rows(weighty) and columns(weightx).
anchor	The anchor property is used to determine where to place the component when the component is smaller than display area in the container.

GridBagLayout Demo Application

Let’s take a look at an example to see how GridBagLayout works.

Here is the screenshot of the GridBagLayout demo application:

package gridbaglayoutdemo;

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

public class Main {
    public static void main(String[] args) {

        JFrame frame = new JFrame("GridBagLayout Demo");
        JButton btn1 = new JButton("Button 1");
        JButton btn2 = new JButton("Button 2");
        JButton btn3 = new JButton("Button 3");
        JButton btn4 = new JButton("Button 4");
        JButton btn5 = new JButton("Button 5");

        JPanel panel = new JPanel(new GridBagLayout());
        GridBagConstraints cst = new GridBagConstraints();

        // add button 1 to the panel
        cst.fill = GridBagConstraints.HORIZONTAL;
	cst.gridx = 0;
	cst.gridy = 0;
        panel.add(btn1,cst);

        // add button 2 to the panel
        cst.fill = GridBagConstraints.HORIZONTAL;

	cst.gridx = 1;
	cst.gridy = 0;
        panel.add(btn2);
         // add button 3 to the panel

	cst.gridx = 2;
	cst.gridy = 0;
	panel.add(btn3, cst);
          // add button 4 to the panel

        cst.fill = GridBagConstraints.HORIZONTAL;
	cst.gridwidth = 3;
	cst.gridx = 0;
	cst.gridy = 1;
        panel.add(btn4,cst);

        // add button 5 to the panel
        cst.fill = GridBagConstraints.HORIZONTAL;
	cst.gridx = 2;
	cst.gridwidth = 1;   
	cst.gridy = 2;       //third row

        panel.add(btn5,cst);

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(300,200);
        frame.getContentPane().add(panel);
        frame.setVisible(true);
    }
}