listsandcomboboxes.java

程序练习中包括书中实例程序代码和练习中要用到的代码,是压缩文件

package examples.windows;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
/** An example class used to demonstrate the use of 
  * the JList and JComboBox components
  */
public class ListsAndComboBoxes extends JFrame {
   private JComboBox crustBox;
   private JList toppingList;

   /** Class constructor method
     * @param titleText Window's title bar text
     */
   public ListsAndComboBoxes( String titleText ) {
      super( titleText );
      addWindowListener( new WindowCloser() );

      crustBox = new JComboBox( new Object[] {
            "thick and chewy",
            "thin and crispy",
            "Chicago deep dish"
         }
      );

      toppingList = new JList( new Object[] {
            "pepperoni",
            "sausage",
            "ham",
            "grilled chicken",
            "mushrooms",
            "green peppers",
            "hot peppers",
            "black olives",
            "tomato slices",
            "sun-dried tomatoes",
            "extra cheese",
            "pineapple",
            "anchovies"
         }
      );
      toppingList.setSelectionMode(
         ListSelectionModel.MULTIPLE_INTERVAL_SELECTION );
      JScrollPane scrollToppingList
         = new JScrollPane( toppingList );

      JPanel lists = new JPanel( new GridBagLayout() );
      GridBagConstraints c = new GridBagConstraints();
      c.fill = GridBagConstraints.HORIZONTAL;
      c.anchor = GridBagConstraints.NORTHWEST;
      c.insets = new Insets( 10, 10, 10, 10 );
      c.weightx = 0.0;
      c.weighty = 0.0;
      lists.add( new JLabel( "Toppings:" ), c );
      c.gridwidth = GridBagConstraints.REMAINDER;
      c.weightx = 1.0;
      c.weighty = 1.0;
      lists.add( scrollToppingList, c );
      c.gridwidth = 1;
      c.weightx = 0.0;
      c.weighty = 0.0;
      lists.add( new JLabel( "Crust type:" ), c );
      c.gridwidth = GridBagConstraints.REMAINDER;
      c.weightx = 1.0;
      c.weighty = 1.0;
      lists.add( crustBox, c );

      JPanel buttons = new JPanel();
      JButton order = new JButton( "Place order",
         new ImageIcon( "pizza.gif" ) );
      order.addActionListener( new ActionListener() {
            public void actionPerformed( ActionEvent e ) {
               confirmOrder();
            }
         }
      );
      buttons.add( order );

      Container cp = getContentPane();
      cp.add( lists, BorderLayout.CENTER );
      cp.add( buttons, BorderLayout.SOUTH );
      setSize( 400, 350 );
      setVisible( true );
   }

   /** Confirm a customer's order
     */
   public void confirmOrder() {
      StringBuffer question = new StringBuffer();
      question.append( "Order a " +
         crustBox.getSelectedItem() +
         " crust pizza topped with" );
      Object[] toppings = toppingList.getSelectedValues();
      for ( int i=0; i < toppings.length; i++ ) {
         question.append( " " + toppings[i] );
         question.append ( ( i + 1 < toppings.length) 
            ? " and" : "?" );
      }
      JOptionPane.showConfirmDialog( this,
                                     question );
   }

   /** The test method for the class
     * @param args not used
     */
   public static void main( String[] args ) {
      new ListsAndComboBoxes( 
         "Example Lists and Combo Boxes" );
   }
}