Java Checkbox Example Tutorial

Checkbox is another Java component used by the programmer when the user is left with two options only – either yes or no, that is, want or don't want. The check box when selected by the user, returns true and when deselected returns false. The checkbox toggles between two states – true or false. The state can be obtained with getState() method.

The Checkbox generates ItemEvent and is handled by ItemListener.

Following is the class signature

public class Checkbox extends Component implements ItemSelectable, Accessible

Example on Java Checkbox Example Tutorial changing the label text as per the check box selected.

import java.awt.*;
import java.awt.event.*;
public class CheckTest extends Frame implements ItemListener
{
  Checkbox nameBox, boldBox, italicBox, exitBox;
  Label lab;
  public CheckTest()
  {
    nameBox = new Checkbox("Monospaced");
    boldBox = new Checkbox("Bold", true);
    italicBox = new Checkbox("Italic");
    lab = new Label("Way 2 Java");

    exitBox = new Checkbox();
    exitBox.setLabel("Close");
    exitBox.setState(false);
    exitBox.setBackground(Color.cyan);
    exitBox.setForeground(Color.blue);
    exitBox.setFont(new Font("Serif", Font.BOLD, 12));

    nameBox.addItemListener(this);
    boldBox.addItemListener(this);
    italicBox.addItemListener(this);
    exitBox.addItemListener(this);

    add(nameBox, "North");
    add(boldBox, "West");
    add(italicBox, "East");
    add(exitBox, "South");
    add(lab, "Center");

    System.out.println("exit box label: " + exitBox.getLabel());
    System.out.println("exit box state: " + exitBox.getState());

    setTitle("Check Boxes in Action");
    setSize(300, 300);               
    setVisible(true);
  }
  public void itemStateChanged(ItemEvent e)
  {
    String fontName = "";
    int b = 0, i = 0;
 
    if(nameBox.getState() == true)
         fontName = "Monospaced";
    else
         fontName = "Dialog";    

    if(boldBox.getState() == true)
         b = Font.BOLD;
    else
         b = Font.PLAIN;

    if(italicBox.getState() == true)
         i = Font.ITALIC;
    else
         i = Font.PLAIN;

    if(exitBox.getState() == true)
         System.exit(0);

    Font f1 = new Font(fontName, b+i, 20);
    lab.setFont(f1);
  }
  public static void main(String args[])
  {
    new CheckTest();
  }
}