JCheckBox

• JCheckBox ref
• How to use buttons

Textbook example

// CheckBoxTest.java
// Creating Checkbox buttons.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class CheckBoxTest extends JFrame {
   private JTextField t;
   private JCheckBox bold, italic;

   public CheckBoxTest()
   {
      super( "JCheckBox Test" );

      Container c = getContentPane();
      c.setLayout(new FlowLayout());

      t = new JTextField( "Watch the font style change", 20 );
      t.setFont( new Font( "TimesRoman", Font.PLAIN, 14 ) );
      c.add( t );

      // create checkbox objects
      bold = new JCheckBox( "Bold" );
      c.add( bold );     

      italic = new JCheckBox( "Italic" );
      c.add( italic );

      CheckBoxHandler handler = new CheckBoxHandler();
      bold.addItemListener( handler );
      italic.addItemListener( handler );

      setSize( 275, 100 );
      show();
   }

   public static void main( String args[] )
   { 
      CheckBoxTest app = new CheckBoxTest();

      app.addWindowListener(
         new WindowAdapter() {
            public void windowClosing( WindowEvent e )
            {
               System.exit( 0 );
            }
         }
      );
   }

   private class CheckBoxHandler implements ItemListener {
      private int valBold = Font.PLAIN;
      private int valItalic = Font.PLAIN;

      public void itemStateChanged( ItemEvent e )
      {
         if ( e.getSource() == bold )
            if ( e.getStateChange() == ItemEvent.SELECTED )
               valBold = Font.BOLD;
            else
               valBold = Font.PLAIN;
               
         if ( e.getSource() == italic )
            if ( e.getStateChange() == ItemEvent.SELECTED )
               valItalic = Font.ITALIC;
            else
               valItalic = Font.PLAIN;

         t.setFont(
            new Font( "TimesRoman", valBold + valItalic, 14 ) );
         t.repaint();
      }
   }
}

Maintained by John Loomis, last updated 1 June 2000