comboboxtest.java

经典的<<C how to program>一书第三版的例程。非常适合于C的初学者。

// Fig. 29.13: 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 images;
   private JLabel label;
   private String names[] =
      { "bug1.gif", "bug2.gif",
        "travelbug.gif", "buganim.gif" };
   private Icon icons[] =
      { new ImageIcon( names[ 0 ] ),
        new ImageIcon( names[ 1 ] ),
        new ImageIcon( names[ 2 ] ),
        new ImageIcon( names[ 3 ] ) };

   public ComboBoxTest()
   {
      super( "Testing JComboBox" );
    
      Container c = getContentPane();
      c.setLayout( new FlowLayout() );      

      images = new JComboBox( names );
      images.setMaximumRowCount( 3 );

      images.addItemListener(
         new ItemListener() {
            public void itemStateChanged( ItemEvent e )
            {
               label.setIcon(
                  icons[ images.getSelectedIndex() ] );
            }
         }
      );

      c.add( images );

      label = new JLabel( icons[ 0 ] );
      c.add( label );

      setSize( 350, 100 );
      show();
   }

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

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

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 * (C) Copyright 2000 by Deitel & Associates, Inc. and Prentice Hall.     *
 * All Rights Reserved.                                                   *
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