Prentice.Hall.Introduction.to.Java.Programming,.Brief.Version.9th.(2014).[sharethefiles.com]

1. Create a menu bar and set it in the applet. Create the menus
Operation and Exit, and add them to the menu bar. Add the menu
items Add, Subtract, Multiply, and Divide under the Operation
menu, and add the menu item Close under the Exit menu.
2. Create a panel to hold labels and text fields, and place the
panel in the center of the applet.
3. Create a panel to hold the four buttons labeled Add, Subtract,
Multiply, and Divide. Place the panel in the south of the applet.
4. Implement the actionPerformed handler to process the events from
the menu items and the buttons.
Listing 38.1 MenuDemo.java
1 import java.awt.*;
2 import java.awt.event.*;
3 import javax.swing.*;
4
5 public class MenuDemo extends JApplet {
6 // Text fields for Number 1, Number 2, and Result
7 private JTextField jtfNum1, jtfNum2, jtfResult;
8
9 // Buttons "Add", "Subtract", "Multiply" and "Divide"
10 private JButton jbtAdd, jbtSub, jbtMul, jbtDiv;
11
12 // Menu items "Add", "Subtract", "Multiply","Divide" and "Close"
13 private JMenuItem jmiAdd, jmiSub, jmiMul, jmiDiv, jmiClose;
14
15 public MenuDemo() {
16 // Create menu bar
17 JMenuBar jmb = new JMenuBar();
18
19 // Set menu bar to the applet
20 setJMenuBar(jmb);
21
22 // Add menu "Operation" to menu bar
23 JMenu operationMenu = new JMenu("Operation");
24 operationMenu.setMnemonic('O');
25 jmb.add(operationMenu);
26
27 // Add menu "Exit" to menu bar
28 JMenu exitMenu = new JMenu("Exit");
29 exitMenu.setMnemonic('E');
30 jmb.add(exitMenu);
31
6