ComboBoxTest.java

// Fig. 13.13: ComboBoxTest.java
// Using a JComboBox to select an image to display.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class ComboBoxTest extends JFrame {
    private JComboBox imagesComboBox;
    private JLabel label;
    private String names[] = { "bug1.jpeg", "bug2.png",  "bug3.jpeg", "bug4.jpeg" };
    private Icon icons[] = { new ImageIcon( names[ 0 ] ),
        new ImageIcon( names[ 1 ] ), new ImageIcon( names[ 2 ] ),
        new ImageIcon( names[ 3 ] ) };

// set up GUI
public ComboBoxTest()
{
super( "Testing JComboBox" ); 
// get content pane and set its layout
Container container = getContentPane();
container.setLayout( new FlowLayout() );  

// set up JComboBox and register its event handler
imagesComboBox = new JComboBox( names );          
imagesComboBox.setMaximumRowCount( 3 );           
imagesComboBox.addItemListener(
new ItemListener() {  // anonymous inner class 
// handle JComboBox event
public void itemStateChanged( ItemEvent event )
{
// determine whether check box selected
if ( event.getStateChange() == ItemEvent.SELECTED )
label.setIcon( icons[ 
imagesComboBox.getSelectedIndex() ] );
}
}  // end anonymous inner class
); // end call to addItemListener                           
container.add( imagesComboBox );
// set up JLabel to display ImageIcons
label = new JLabel( icons[ 0 ] );
container.add( label );
setSize( 350, 100 );
setVisible( true );
} // end ComboBoxTest constructor
public static void main( String args[] )
{ 
ComboBoxTest application = new ComboBoxTest();
application.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
}
} // end class ComboBoxTest