JCheckBox Java

JCheckBox is a Swing component that represents an item which shows a state of selected or unselected. User can change this state by clicking on the check box of the component. Here is a typical JCheckBox component in default Java look and feel:

A standard JCheckBox component contains a check box and a label that describes purpose of the check box. An icon and mnemonic key also can be set for this component.

Class Declaration

Following is the declaration for javax.swing.JCheckBox class −

public class JCheckBox
   extends JToggleButton
      implements Accessible

Field

Following are the fields for javax.swing.JCheckBox class −

static String BORDER_PAINTED_FLAT_CHANGED_PROPERTY − Identifies a change to the flat property.

Class Constructors

Sr.No.	Constructor & Description
1	JCheckBox() Creates an initially unselected check box button with no text and no icon.
2	JCheckBox(Action a) Creates a checkbox where the properties are taken from the Action supplied.
3	JCheckBox(Icon icon) Creates an initially unselected checkbox with an icon.
4	JCheckBox(Icon icon, boolean selected) Creates a checkbox with an icon and specifies whether or not it is initially selected.
5	JCheckBox(String text) Creates an initially unselected checkbox with text.
6	JCheckBox(String text, boolean selected) Creates a checkbox with the text and specifies whether or not it is initially selected.
7	JCheckBox(String text, Icon icon) Creates an initially unselected checkbox with the specified text and icon.
8	JCheckBox(String text, Icon icon, boolean selected) Creates a checkbox with text and icon, and specifies whether or not it is initially selected.

Class Methods

Sr.No.	Method & Description
1	AccessibleContext getAccessibleContext() Gets the AccessibleContext associated with this JCheckBox.
2	String getUIClassID() Returns a string that specifies the name of the L&F class which renders this component.
3	boolean isBorderPaintedFlat() Gets the value of the borderPaintedFlat property.
4	protected String paramString() Returns a string representation of this JCheckBox.
5	void setBorderPaintedFlat(boolean b) Sets the borderPaintedFlat property, which gives a hint to the look and feel as to the appearance of the checkbox border.
6	void updateUI() Resets the UI property to a value from the current look and feel.

Methods Inherited

This class inherits methods from the following classes −

• javax.swing.AbstractButton
• javax.swing.JToggleButton
• javax.swing.JComponent
• java.awt.Container
• java.awt.Component
• java.lang.Object

JCheckBox Example

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

JCheckboxDemo.java

package com.sjavaspot.gui;
 
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
 
public class JCheckBoxDemo {
   private JFrame mainFrame;
   private JLabel headerLabel;
   private JLabel statusLabel;
   private JPanel controlPanel;

   public JCheckBoxDemo(){
      prepareGUI();
   }
   public static void main(String[] args){
      JCheckBoxDemo  jcheckBoxDemo = new JCheckBoxDemo();            

jcheckBoxDemo.showCheckBoxDemo();
   }
   private void prepareGUI(){
      mainFrame = new JFrame("Java Swing Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));
      
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
      headerLabel = new JLabel("", JLabel.CENTER);        
      statusLabel = new JLabel("",JLabel.CENTER);    
      statusLabel.setSize(350,100);

      controlPanel = new JPanel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }
   private void showCheckBoxDemo(){
      headerLabel.setText("Control in action: CheckBox"); 

      final JCheckBox chkApple = new JCheckBox("Apple");
      final JCheckBox chkMango = new JCheckBox("Mango");
      final JCheckBox chkPeer = new JCheckBox("Peer");

      chkApple.setMnemonic(KeyEvent.VK_C);
      chkMango.setMnemonic(KeyEvent.VK_M);
      chkPeer.setMnemonic(KeyEvent.VK_P);

      chkApple.addItemListener(new ItemListener() {
         public void itemStateChanged(ItemEvent e) {         
            statusLabel.setText("Apple Checkbox: " 
               + (e.getStateChange()==1?"checked":"unchecked"));
         }           
      });
      chkMango.addItemListener(new ItemListener() {
         public void itemStateChanged(ItemEvent e) {             
            statusLabel.setText("Mango Checkbox: " 
               + (e.getStateChange()==1?"checked":"unchecked")); 
         }           
      });
      chkPeer.addItemListener(new ItemListener() {
         public void itemStateChanged(ItemEvent e) {             
            statusLabel.setText("Peer Checkbox: " 
               + (e.getStateChange()==1?"checked":"unchecked"));
         }           
      });
      controlPanel.add(chkApple);
      controlPanel.add(chkMango);
      controlPanel.add(chkPeer);       

      mainFrame.setVisible(true);  
   }
}

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

D:\SWING>javac com\sjavaspot\gui\JCheckboxDemo.java

If no error occurs, it means the compilation is successful. Run the program using the following command.

D:\SWING>java com.sjavaspot.gui.JCheckboxDemo

Verify the following output.