Creating Menus and Button Arrays Using the Abstract Windows Toolkit - Java Programming: Comprehensive Concepts and Techniques - page 389

Creating Menus
Most applications contain a menu bar with commands that a user can click to
display a menu; each menu, in turn, includes commands that a user can click to
perform certain actions. Table 6-3 lists Java's menu components. The MenuBar
component is used to construct an instance of a menu bar. The Menu compo-
nent with its Menu() constructor method creates a new menu command on the
menu bar using the specified label. A second boolean argument indicates
whether or not the menu can be implemented as a tear-off menu , which
remains on the screen after the user releases the mouse button. On platforms
that do not support tear-off menus, the tear-off property is ignored. The
MenuItem component adds a command to a previously declared Menu
component, thus resulting in a new command on the drop-down menu. Each
of the Java menu components has an associated constructor method, as shown
in Table 6-3.

Table 6-3 Java Menu Components
MENU COMPONENT

DESCRIPTION CONSTRUCTOR METHOD

MenuBar creates a menu bar

MenuBar mnuBar = new MenuBar();

Menu creates a menu bar

Menu mnuEdit = new Menu("Edit",

command true);

MenuItem creates a command

MenuItem mnuEditCopy = new

on a menu MenuItem("Copy");

After the menu components are constructed, programmers use a variety of
methods to assign and populate the menus. Table 6-4 displays some of the more
common methods related to menus.

Table 6-4 Menu Methods

METHOD DESCRIPTION EXAMPLE

setMenuBar() automatically displays a previously setMenuBar(myMenu);

constructed menu bar at the top of the
Frame

add() adds a command to a menu bar or menu

myMenu.add(mnuHelp);
mnuHelp.add(mnuHelpAbout);

addActionListener() makes the menu item clickable mnuEditCut.addActionListener(this);

setActionCommand() sets a String to represent the action of

mnuEdit.setActionCommand("Edit");

the menu

remove() removes a menu item from a menu bar remove(mnuTools);

or menu

insertSeparator() inserts a horizontal separator line at the mnuTable.insertSeparator(1);

index position