SWING - GridBagLayout Class

Introduction

The class GridBagLayout arranges components in a horizontal and vertical manner.

Class declaration

Following is the declaration for java.awt.GridBagLayout class:

public class GridBagLayout
   extends Object
      implements LayoutManager2, Serializable

Field

Following are the fields for java.awt.GridBagLayout class:

static int DEFAULT_SIZE -- Indicates the size from the component or gap should be used for a particular range value.
static int PREFERRED_SIZE -- Indicates the preferred size from the component or gap should be used for a particular range value.

Class constructors

S.N.	Constructor & Description
1	GridBagLayout() Creates a grid bag layout manager.

Class methods

S.N.	Method & Description
1	void addLayoutComponent(Component comp, Object constraints) Adds the specified component to the layout, using the specified constraints object.
2	void addLayoutComponent(String name, Component comp) Adds the specified component with the specified name to the layout.
3	protected void adjustForGravity(GridBagConstraints constraints, Rectangle r) Adjusts the x, y, width, and height fields to the correct values depending on the constraint geometry and pads.
4	protected void AdjustForGravity(GridBagConstraints constraints, Rectangle r) This method is obsolete and supplied for backwards compatability only; new code should call adjustForGravity instead.
5	protected void arrangeGrid(Container parent) Lays out the grid.
6	protected void ArrangeGrid(Container parent) This method is obsolete and supplied for backwards compatability only; new code should call arrangeGrid instead.
7	GridBagConstraints getConstraints(Component comp) Gets the constraints for the specified component.
8	float getLayoutAlignmentX(Container parent) Returns the alignment along the x axis.
9	float getLayoutAlignmentY(Container parent) Returns the alignment along the y axis.
10	int[][] getLayoutDimensions() Determines column widths and row heights for the layout grid.
11	protected java.awt.GridBagLayoutInfo getLayoutInfo(Container parent, int sizeflag) Fills in an instance of GridBagLayoutInfo for the current set of managed children.
12	protected java.awt.GridBagLayoutInfo GetLayoutInfo(Container parent, int sizeflag) This method is obsolete and supplied for backwards compatability only; new code should call getLayoutInfo instead.
13	Point getLayoutOrigin() Determines the origin of the layout area, in the graphics coordinate space of the target container.
14	double[][] getLayoutWeights() Determines the weights of the layout grid's columns and rows.
15	protected Dimension getMinSize(Container parent, java.awt.GridBagLayoutInfo info) Figures out the minimum size of the master based on the information from getLayoutInfo().
16	protected Dimension GetMinSize(Container parent, java.awt.GridBagLayoutInfo info) This method is obsolete and supplied for backwards compatability only; new code should call getMinSize instead.
17	void invalidateLayout(Container target) Invalidates the layout, indicating that if the layout manager has cached information it should be discarded.
18	void layoutContainer(Container parent) Lays out the specified container using this grid bag layout.
19	Point location(int x, int y) Determines which cell in the layout grid contains the point specified by (x, y).
20	protected GridBagConstraints lookupConstraints(Component comp) Retrieves the constraints for the specified component.
21	Dimension maximumLayoutSize(Container target) Returns the maximum dimensions for this layout given the components in the specified target container.
22	Dimension minimumLayoutSize(Container parent) Determines the minimum size of the parent container using this grid bag layout.
23	Dimension preferredLayoutSize(Container parent) Determines the preferred size of the parent container using this grid bag layout.
24	void removeLayoutComponent(Component comp) Removes the specified component from this layout.
25	void setConstraints(Component comp, GridBagConstraints constraints) Sets the constraints for the specified component in this layout.
26	String toString() Returns a string representation of this grid bag layout's values.

Methods inherited

This class inherits methods from the following classes:

java.lang.Object

GridBagLayout Example

Create the following java program using any editor of your choice in say D:/ > SWING > com > tutorialspoint > gui >

SwingLayoutDemo.java

package com.tutorialspoint.gui;

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

public class SwingLayoutDemo {
   private JFrame mainFrame;
   private JLabel headerLabel;
   private JLabel statusLabel;
   private JPanel controlPanel;
   private JLabel msglabel;

   public SwingLayoutDemo(){
      prepareGUI();
   }

   public static void main(String[] args){
      SwingLayoutDemo swingLayoutDemo = new SwingLayoutDemo();  
      swingLayoutDemo.showGridBagLayoutDemo();       
   }
      
   private void prepareGUI(){
      mainFrame = new JFrame("Java SWING Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));

      headerLabel = new JLabel("",JLabel.CENTER );
      statusLabel = new JLabel("",JLabel.CENTER);        

      statusLabel.setSize(350,100);
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
      controlPanel = new JPanel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }

   private void showGridBagLayoutDemo(){
      headerLabel.setText("Layout in action: GridBagLayout");      

      JPanel panel = new JPanel();
      panel.setBackground(Color.darkGray);
      panel.setSize(300,300);
      GridBagLayout layout = new GridBagLayout();

      panel.setLayout(layout);        
      GridBagConstraints gbc = new GridBagConstraints();

      gbc.fill = GridBagConstraints.HORIZONTAL;
      gbc.gridx = 0;
      gbc.gridy = 0;
      panel.add(new JButton("Button 1"),gbc);

      gbc.gridx = 1;
      gbc.gridy = 0;
      panel.add(new JButton("Button 2"),gbc); 

      gbc.fill = GridBagConstraints.HORIZONTAL;
      gbc.ipady = 20;   
      gbc.gridx = 0;
      gbc.gridy = 1;
      panel.add(new JButton("Button 3"),gbc); 

      gbc.gridx = 1;
      gbc.gridy = 1;       
      panel.add(new JButton("Button 4"),gbc);  

      gbc.gridx = 0;
      gbc.gridy = 2;      
      gbc.fill = GridBagConstraints.HORIZONTAL;
      gbc.gridwidth = 2;
      panel.add(new JButton("Button 5"),gbc);  

      controlPanel.add(panel);

      mainFrame.setVisible(true);  
   }
}

Compile the program using command prompt. Go to D:/ > SWING and type the following command.

D:\SWING>javac com\tutorialspoint\gui\SwingLayoutDemo.java

If no error comes that means compilation is successful. Run the program using following command.

D:\SWING>java com.tutorialspoint.gui.SwingLayoutDemo

Verify the following output

swing_layouts.htm