MenuWindow

MenuWindow.java

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

/**
The MenuWindow class demonstrates a menu system.
*/

public class MenuWindow extends JFrame
{
   private JLabel messageLabel; // Displays a message
   private final int LABEL_WIDTH = 400; // Label's width
   private final int LABEL_HEIGHT = 200; // Label's height

   // The following will reference menu components.
   private JMenuBar menuBar; // The menu bar
   private JMenu fileMenu; // The File menu
   private JMenu textMenu; // The Text menu
   private JMenuItem exitItem; // To exit
   private JRadioButtonMenuItem blackItem; // Makes text black
   private JRadioButtonMenuItem redItem; // Makes text red
   private JRadioButtonMenuItem blueItem; // Makes text blue
   private JCheckBoxMenuItem visibleItem; // Toggle visibility

   /**
Constructor
*/

   public MenuWindow()
   {
      // Set the title.
      setTitle("Example Menu System");

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

      // Create the messageLabel label.
      messageLabel = new JLabel("Use the Text menu to " +
            "change my color and make me invisible.",
             SwingConstants.CENTER);

      // Set the label's preferred size.
      messageLabel.setPreferredSize(
             new Dimension(LABEL_WIDTH, LABEL_HEIGHT));

      // Set the label's foreground color.
      messageLabel.setForeground(Color.black);

      // Add the label to the content pane.
      add(messageLabel);

      // Build the menu bar.
      buildMenuBar();

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

   /**
The buildMenuBar method builds the menu bar.
*/

   private void buildMenuBar()
   {
      // Create the menu bar.
      menuBar = new JMenuBar();

      // Create the file and text menus.
      buildFileMenu();
      buildTextMenu();

      // Add the file and text menus to the menu bar.
      menuBar.add(fileMenu);
      menuBar.add(textMenu);

      // Set the window's menu bar.
      setJMenuBar(menuBar);
   }

   /**
The buildFileMenu method builds the File menu
and returns a reference to its JMenu object.
*/

   private void buildFileMenu()
   {
      // Create an Exit menu item.
      exitItem = new JMenuItem("Exit");
      exitItem.setMnemonic(KeyEvent.VK_X);
      exitItem.addActionListener(new ExitListener());

      // Create a JMenu object for the File menu.
      fileMenu = new JMenu("File");
      fileMenu.setMnemonic(KeyEvent.VK_F);

      // Add the Exit menu item to the File menu.
      fileMenu.add(exitItem);
   }

   /**
The buildTextMenu method builds the Text menu
and returns a reference to its JMenu object.
*/

   private void buildTextMenu()
   {
      // Create the radio button menu items to change
      // the color of the text. Add an action listener
      // to each one.
      blackItem = new JRadioButtonMenuItem("Black", true);
      blackItem.setMnemonic(KeyEvent.VK_B);
      blackItem.addActionListener(new ColorListener());

      redItem = new JRadioButtonMenuItem("Red");
      redItem.setMnemonic(KeyEvent.VK_R);
      redItem.addActionListener(new ColorListener());

      blueItem = new JRadioButtonMenuItem("Blue");
      blueItem.setMnemonic(KeyEvent.VK_U);
      blueItem.addActionListener(new ColorListener());

      // Create a button group for the radio button items.
      ButtonGroup group = new ButtonGroup();
      group.add(blackItem);
      group.add(redItem);
      group.add(blueItem);

      // Create a check box menu item to make the text
      // visible or invisible.
      visibleItem = new JCheckBoxMenuItem("Visible", true);
      visibleItem.setMnemonic(KeyEvent.VK_V);
      visibleItem.addActionListener(new VisibleListener());

      // Create a JMenu object for the Text menu.
      textMenu = new JMenu("Text");
      textMenu.setMnemonic(KeyEvent.VK_T);

      // Add the menu items to the Text menu.
      textMenu.add(blackItem);
      textMenu.add(redItem);
      textMenu.add(blueItem);
      textMenu.addSeparator(); // Add a separator bar.
      textMenu.add(visibleItem);
   }

   /**
Private inner class that handles the event that
is generated when the user selects Exit from
the File menu.
*/

    private class ExitListener implements ActionListener
    {
       public void actionPerformed(ActionEvent e)
       {
          System.exit(0);
       }
    }

   /**
Private inner class that handles the event that
is generated when the user selects a color from
the Text menu.
*/

    private class ColorListener implements ActionListener
    {
       public void actionPerformed(ActionEvent e)
       {
          if (blackItem.isSelected())
             messageLabel.setForeground(Color.black);
          else if (redItem.isSelected())
             messageLabel.setForeground(Color.red);
          else if (blueItem.isSelected())
             messageLabel.setForeground(Color.blue);
       }
    }

   /**
Private inner class that handles the event that
is generated when the user selects Visible from
the Text menu.
*/

   private class VisibleListener implements ActionListener
   {
      public void actionPerformed(ActionEvent e)
      {
         if (visibleItem.isSelected())
            messageLabel.setVisible(true);
         else
            messageLabel.setVisible(false);
      }
   }

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

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