Simple Menu Program In Java

Java Swing: Menus and Toolbars, Part 1. O'Reilly Book. Excerpts: Java Swing, 2nd Edition. Robert Eckstein, Marc Loy, Dave Wood, James Elliott, Brian Cole. In part one in this excerpt on menus and toolbars from O'Reilly Java Swing, 2nd Edition, get an introduction to Swing menus. This chapter discusses Swing menus and toolbars. Menus are the richer and more flexible of the two, so they encompass most of the chapter. They tend to be the first thing users explore in learning a new application, so it's fitting that Swing provides a great deal of freedom in laying out menu components.

Toolbars allow you to group buttons, combo boxes, and other elements together in repositionable panels; these tools can assist the user in performing many common tasks. You can add any component to a Swing toolbar, even non- Swing components.

In addition, Swing allows the toolbar to be dragged from the frame and positioned inside a child window for convenience. Introducing Swing Menus. Swing menu components are subclasses of JComponent.

How to Program in Java. To program in Java (not JavaScript, an unrelated language). Can you please put wikiHow on the whitelist for your ad blocker? Menu-driven 'bank account' application. In current practice lesson we are going to develop a menu-driven application to manage simple. Menus and toolbars in Java Swing.

Java examples (Java sample source code) help to understand functionality of various Java classes and methods as well as various programming techniques in a simple. Creating a console menu for user to make a selection. Doing a program in Eclipse with Java. Java Menu Loop Problems; Program loops too soon? Example of a menu driven program create a simple calculator that will add subtract multiply and divide values entered by the user */ import java.util.*; //used to.

Consequently, they have all the benefits of a Swing component, and you can treat them as such with respect to layout managers and containers. Here are some notable features of the Swing menu system: Icons can augment or replace menu items. Menu items can be radio buttons. Keyboard accelerators can be assigned to menu items; these appear next to the menu item text. Most standard Swing components can be used as menu items. Swing provides familiar menu separators, checkbox menu items, pop- up menus, and submenus for use in your applications.

In addition, Swing menus support keyboard accelerators and . On the Macintosh, your application can be configured so that this method places the menu bar at the top of the screen, where users expect to find it. Figure 1. 4- 1 defines the various elements that make up the menu system in Swing. Figure 1. 4- 1. The elements of the Swing menu system. Note that not all platforms support underline- style mnemonics.

Notably, on the Macintosh (which has never provided this sort of user interface) mnemonics do not appear at all in the system menu bar, and though they are visible in the actual menus, they do not work in either place. If your application uses mnemonics, you should consider grouping the code to set them up into a separate method that is invoked only when running on a platform that supports them. All platforms do support accelerators (shortcuts) but have different conventions about the key used to invoke them. You can take advantage of the Toolkit method get.

Menu. Shortcut. Key. Mask to always use the right key. Menu Hierarchy. The class diagram for Swing menus is shown in Figure 1. Figure 1. 4- 2. Swing menu diagram. You might be surprised to find Abstract. Button in the hierarchy, but menus and menu items have many features in common with Swing buttons.

For example, menu items can be highlighted (when the mouse pointer passes over them), they can be clicked to indicate that the user has made a choice, they can be disabled and grayed like buttons, and they can be assigned action commands to assist with event handling. JCheck. Box. Menu.

Item and JRadio. Button. Menu. Item can even be toggled between two selection states. Since Swing menu components share much of the functionality of Swing buttons, it is appropriate and efficient that they inherit from Abstract.

Button. It may also seem surprising that JMenu inherits from JMenu. Item, instead of vice- versa. This is because each JMenu contains an implicit menu item that serves as the title of the menu. You'll often hear this part of the menu called the title button. When the user presses or drags the mouse cursor over the title button, the corresponding menu appears. Note, however, that menus do not have to be anchored to a menu bar. You can embed them in other menus, where they act as submenus.

This means that the title button must be able to act as a menu item, which would not be possible if the hierarchy was reversed. We discuss this behavior in more detail when we cover the JMenu class later in this chapter. Almost all of the menu classes implement the Menu. Element interface.

The Menu. Element interface outlines standardized methods that dictate how each Swing menu component behaves when it encounters user input, such as keyboard or mouse events. Swing menu classes typically process these mouse and keyboard events and pass notifications to the component delegates, which handle any necessary redrawing of the component. These methods work in tandem with the Menu. Selection. Manager class.

While you rarely need to implement the Menu. Element interface, it helps to know how it works. We show how to implement this interface later in the chapter.

Getting Your Feet Wet. Okay, it's time to jump in. Here is a flashy program that introduces much of the basic Swing menu functionality: // Intro.

Example. java. import java. Intro. Example extends JMenu. Bar . Figure 1. 4- 3 shows a mosaic of the different menus that the program produces. It also shows how the Edit menu looks on two different platforms, with the proper accelerator key (Control or Command) used on each. A sample of Swing menu effects. In the third menu, we've enhanced the last item with a GIF image of a potted plant.

In addition, the first menu item in the Other menu is actually a submenu that pops out to a second submenu, underscoring the recursive nature of menus. If you select any of the menus, you are rewarded with a simple text output that tells you what you clicked: Menu item . We will examine each menu component in detail shortly. In the next installment, learn about menu bar selection models. Return to ONJava.