// Fig. 12.12: RadioButtonTest.java

// Creating radio buttons using ButtonGroup and JRadioButton.

// Java core packages

import java.awt.*;

import java.awt.event.*;

// Java extension packages

import javax.swing.*;

public class RadioButtonTest extends JFrame {

private JTextField field;

private Font plainFont, boldFont, italicFont, boldItalicFont;

private JRadioButton plainButton, boldButton, italicButton,

boldItalicButton;

private ButtonGroup radioGroup;

// create GUI and fonts

public RadioButtonTest()

{

super( "RadioButton Test" );

// get content pane and set its layout

Container container = getContentPane();

container.setLayout( new FlowLayout() );

// set up JTextField

field =

new JTextField( "Watch the font style change", 25 );

container.add( field );

// create radio buttons

plainButton = new JRadioButton( "Plain", true );

container.add( plainButton );

boldButton = new JRadioButton( "Bold", false );

container.add( boldButton );

italicButton = new JRadioButton( "Italic", false );

container.add( italicButton );

boldItalicButton = new JRadioButton(

"Bold/Italic", false );

container.add( boldItalicButton );

// register events for JRadioButtons

RadioButtonHandler handler = new RadioButtonHandler();

plainButton.addItemListener( handler );

boldButton.addItemListener( handler );

italicButton.addItemListener( handler );

boldItalicButton.addItemListener( handler );

// create logical relationship between JRadioButtons

radioGroup = new ButtonGroup();

radioGroup.add( plainButton );

radioGroup.add( boldButton );

radioGroup.add( italicButton );

radioGroup.add( boldItalicButton );

// create font objects

plainFont = new Font( "Serif", Font.PLAIN, 14 );

boldFont = new Font( "Serif", Font.BOLD, 14 );

italicFont = new Font( "Serif", Font.ITALIC, 14 );

boldItalicFont =

new Font( "Serif", Font.BOLD + Font.ITALIC, 14 );

field.setFont( plainFont );

setSize( 300, 100 );

setVisible( true );

}

// execute application

public static void main( String args[] )

{

RadioButtonTest application = new RadioButtonTest();

application.addWindowListener(new WindowAdapter()

{ public void windowClosing( WindowEvent event )

{

System.exit( 0 );

}

}

);

}

// private inner class to handle radio button events

private class RadioButtonHandler implements ItemListener {

// handle radio button events

public void itemStateChanged( ItemEvent event )

{

// user clicked plainButton

if ( event.getSource() == plainButton )

field.setFont( plainFont );

// user clicked boldButton

else if ( event.getSource() == boldButton )

field.setFont( boldFont );

// user clicked italicButton

else if ( event.getSource() == italicButton )

field.setFont( italicFont );

// user clicked boldItalicButton

else if ( event.getSource() == boldItalicButton )

field.setFont( boldItalicFont );

}

} // end private inner class RadioButtonHandler

} // end class RadioButtonTest