Java AWT | GridBagLayout Class

Last Updated : 20 Aug, 2018

GridBagLayout class is a flexible layout manager. It is used to aligns the components horizontally, vertically or along their baseline. It doesn’t require the components of the same size. Each GridBagLayout object manages a rectangular grid of cells, dynamic with each component occupying one or more cells, called its display area. GridBagLayout components are associated with the instance of GridBagConstraints. These constraints are used to define the component’s display area and their positions. In addition to its constraints object, the GridBagLayout also considers each component’s minimum and preferred sizes in order to determine a component’s size. GridBagLayout components are also arranged in the rectangular grid but can have different sizes and can occupy the multiple rows or columns.

Constructor:

GridBagLayout(): It is used to creates a grid bag layout manager.

Commonly Used Methods:

removeLayoutComponent(Component cmp): Removes the specified component from this layout.
getLayoutAlignmentY(Container p): Returns the alignment along the y-axis.
addLayoutComponent(Component cmp, Object cons): Add the specified component with the specified name to the layout.
toString(): Returns a string representation of this grid bag layout’s values.
getLayoutAlignmentX(Container p): Returns the alignment along the x-axis.
getConstraints(Component cmp): Gets the constraints for the specified component.
maximumLayoutSize(Container tar): Returns the maximum dimensions for this layout given the components in the specified target container.
minimumLayoutSize(Container par): Determines the minimum size of the parent container using this grid bag layout.

Below programs illustrate the GridBagLayout class:

Program 1: Below program arranges the several row and column components in a JFrame, whose instance class is named as “Gridbagdemo”. We create 4 JButton components named “java“, “layout“, “manager“, “demo” and then add them to the JFrame by the method add(). We set the size and visibility of the frame by method setSize() and setVisible(). The layout is set by the method setLayout().

// Java program to demonstrate GridBagLayout class.
import java.awt.*;
import java.awt.event.*;
import javax.swing.JFrame;
import javax.swing.*;
  
// class extends JFrame
public class GridbagDemo extends JFrame {
  
    GridbagDemo()
    {
  
        // Function to set title of JFrame.
        setTitle("GridBagLayoutDemo");
  
        // Creating Object of Jpanel class
        JPanel p = new JPanel();
  
        // set the layout
        p.setLayout(new GridBagLayout());
  
        // creates a constraints object
        GridBagConstraints c = new GridBagConstraints();
  
        // insets for all components
        c.insets = new Insets(2, 2, 2, 2);
  
        // column 0
        c.gridx = 0;
  
        // row 0
        c.gridy = 0;
  
        // increases components width by 10 pixels
        c.ipadx = 15;
  
        // increases components height by 50 pixels
        c.ipady = 50;
  
        // constraints passed in
        p.add(new JButton("Java Swing"), c);
  
        // column 1
        c.gridx = 1;
  
        // increases components width by 70 pixels
        c.ipadx = 90;
  
        // increases components height by 40 pixels
        c.ipady = 40;
  
        // constraints passed in
        p.add(new JButton("Layout"), c);
  
        // column 0
        c.gridx = 0;
  
        // row 2
        c.gridy = 1;
  
        // increases components width by 20 pixels
        c.ipadx = 20;
  
        // increases components height by 20 pixels
        c.ipady = 20;
  
        // constraints passed in
        p.add(new JButton("Manager"), c);
  
        // increases components width by 10 pixels
        c.ipadx = 10;
  
        // column 1
        c.gridx = 1;
  
        // constraints passed in
        p.add(new JButton("Demo"), c);
  
        // Creating Object of "wndcloser" 
        // class of windowlistener
        WindowListener wndCloser = new WindowAdapter() {
  
            public void windowClosing(WindowEvent e)
            {
  
                // exit the system
                System.exit(0);
            }
        };
  
        // add the actionwindowlistener
        addWindowListener(wndCloser);
  
        // add the content
        getContentPane().add(p);
  
        // Function to set size of JFrame.
        setSize(600, 400);
  
        // Function to set visiblity of JFrame.
        setVisible(true);
    }
  
    // Main Method
    public static void main(String[] args)
    {
  
        // calling the constructor
        new GridbagDemo();
    }
}

Output:

Program 2: Below program arranges the several row and column components in a JFrame, whose instance class is named as “Gridbagdemo”. We create 5 JButton components and then add them to the JFrame by the method add(). We set the title, size and visibility of the frame by method setTitle, setSize() and setVisible(). The layout is set by the method setLayout().

// Java program to demonstrate GridBagLayout class.
import java.awt.*;
import javax.swing.JButton;
import javax.swing.JFrame;
   
// Constructor of GridBagLayout class.
public class GridBagLayoutDemo {
   
    final static boolean shouldFill = true;
    final static boolean shouldWeightX = true;
    final static boolean RIGHT_TO_LEFT = false;
   
public static void addComponentsToPane(Container pane)
{
  
    // if condition
    if (RIGHT_TO_LEFT) {
  
        pane.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
    }
  
    // Declaration of objects of JButton class
    JButton button;
  
    // set the layout
    pane.setLayout(new GridBagLayout());
  
    // creates a constraints object
    GridBagConstraints c = new GridBagConstraints();
  
    // if condition
    if (shouldFill) {
  
        // natural height, maximum width
        c.fill = GridBagConstraints.HORIZONTAL;
    }
  
    // Initialization of object 
    // "button" of JButton class.
    button = new JButton("Button 1");
  
    // if condition
    if (shouldWeightX) {
        c.weightx = 0.5;
    }
  
    // column 0
    c.gridx = 0;
  
    // row 0
    c.gridy = 0;
  
    // Adding JButton "button" on JFrame.
    pane.add(button, c);
  
    // Initialization of object
    // "button" of JButton class.
    button = new JButton("Button 2");
  
    // column 1
    c.gridx = 1;
  
    // row 0
    c.gridy = 0;
  
    // Adding JButton "button" on JFrame.
    pane.add(button, c);
  
    // Initialization of object
    // "button" of JButton class.
    button = new JButton("Button 3");
  
    // column 1
    c.gridx = 2;
  
    // row 0
    c.gridy = 0;
  
    // Adding JButton "button" on JFrame.
    pane.add(button, c);
  
    // Initialization of object 
    // "button" of JButton class.
    button = new JButton("Long-Named Button 4");
  
    // increases components height by 40 pixels
    c.ipady = 40;
  
    // column width 0
    c.weightx = 0.0;
  
    // row width 3
    c.gridwidth = 3;
  
    // column 1
    c.gridx = 0;
  
    // row 1
    c.gridy = 1;
  
    // Adding JButton "button" on JFrame.
    pane.add(button, c);
  
    // Initialization of object 
    // "button" of JButton class.
    button = new JButton("Button 5");
  
    // increases components height by 0 pixels
    c.ipady = 0;
  
    // request any extra vertical space
    c.weighty = 1.0;
  
    // bottom of space
    c.anchor = GridBagConstraints.PAGE_END;
  
    // top padding
    c.insets = new Insets(10, 0, 0, 0);
  
    // column 2
    c.gridx = 1;
  
    // 2 columns wide
    c.gridwidth = 2;
  
    // row 3
    c.gridy = 2;
  
    // Adding JButton "button" on JFrame.
    pane.add(button, c);
}
  
// Create the GUI and show it.  For thread safety,
// this method should be invoked from the
// event-dispatching thread.
private static void createAndShowGUI()
{
  
    // to set a Jframe default
    JFrame.setDefaultLookAndFeelDecorated(true);
  
    // Create and set up the window.
    JFrame frame = new JFrame("GridBagLayoutDemo");
  
    // Function to close the operation of JFrame.
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  
    // adding the content pane.
    addComponentsToPane(frame.getContentPane());
  
    // Display the window.
    frame.pack();
  
    // Function to set visible status of JFrame.
    frame.setVisible(true);
}
  
    // Main Method
    public static void main(String[] args)
    {
   
        // Schedule a job for the event-dispatching thread:
        // creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
   
            public void run()
            {
                createAndShowGUI();
            }
        });
    }
}

Output:

Note: The above programs might not run in an online IDE. Please use an offline compiler.

Reference: https://docs.oracle.com/javase/7/docs/api/java/awt/GridBagLayout.html

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