ListWindow

ListWindow.java

import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;

/**
This class demonstrates the List Component.
*/

public class ListWindow extends JFrame
{
   private JPanel monthPanel; // To hold components
   private JPanel selectedMonthPanel; // To hold components
   private JList monthList; // The months
   private JTextField selectedMonth; // The selected month
   private JLabel label; // A message

   // The following array holds the values that will
   // be displayed in the monthList list component.
   private String[] months = { "January", "February",
            "March", "April", "May", "June", "July",
            "August", "September", "October", "November",
            "December" };

   /**
Constructor
*/

   public ListWindow()
   {
      // Set the title.
      setTitle("List Demo");

      // Specify an action for the close button.
      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

      // Add a BorderLayout manager.
      setLayout(new BorderLayout());

      // Build the month and selectedMonth panels.
      buildMonthPanel();
      buildSelectedMonthPanel();

      // Add the panels to the content pane.
      add(monthPanel, BorderLayout.CENTER);
      add(selectedMonthPanel, BorderLayout.SOUTH);

      // Pack and display the window.
      pack();
      setVisible(true);
   }

   /**
The buildMonthPanel method adds a list containing
the names of the months to a panel.
*/

   private void buildMonthPanel()
   {
      // Create a panel to hold the list.
      monthPanel = new JPanel();

      // Create the list.
      monthList = new JList(months);

      // Set the selection mode to single selection.
      monthList.setSelectionMode(
                ListSelectionModel.SINGLE_SELECTION);

      // Register the list selection listener.
      monthList.addListSelectionListener(
                                 new ListListener());

      // Add the list to the panel.
      monthPanel.add(monthList);
   }

   /**
The buildSelectedMonthPanel method adds an
uneditable text field to a panel.
*/

   private void buildSelectedMonthPanel()
   {
      // Create a panel to hold the text field.
      selectedMonthPanel = new JPanel();

      // Create the label.
      label = new JLabel("You selected: ");

      // Create the text field.
      selectedMonth = new JTextField(10);

      // Make the text field uneditable.
      selectedMonth.setEditable(false);

      // Add the label and text field to the panel.
      selectedMonthPanel.add(label);
      selectedMonthPanel.add(selectedMonth);
   }

   /**
Private inner class that handles the event when
the user selects an item from the list.
*/

   private class ListListener
                    implements ListSelectionListener
   {
      public void valueChanged(ListSelectionEvent e)
      {
         // Get the selected month.
         String selection =
               (String) monthList.getSelectedValue();

         // Put the selected month in the text field.
         selectedMonth.setText(selection);
      }
   }

   /**
The main method creates an instance of the
ListWindow class which causes it to display
its window.
*/

     public static void main(String[] args)
     {
          new ListWindow();
     }
}