CHAPTER 8 Object Palette

---

This chapter will discuss the Object Palette and how to use it to assemble Graphical User Interfaces for Mobile Devices.

It will discuss

• Assembling parts
• An overview of the Mobile Devices Palette
• Each of the parts on the Mobile Devices Palette

Assembling A Program Using The Mobile Devices Palette

When a Composer is opened from the IDE, two additional windows are created: the Mobile Devices Palette and the MID Emulator.

Mobile Devices Palette

The Palette contains all of the graphical parts which are available to be used in a MIDlet. To add a part to the MIDlet, drag it from the Palette to the Parts tree in the Composer. Each part in the Palette has specific places where it can be dropped. If a part is dragged to an inappropriate place, a symbol will appear in the tree indicating that it cannot be dropped there.

The GUI of a MIDlet is organized around the concept of the display. Each MIDlet has one display, which can display one of five basic displayables at any time. These displayables are the Alert, Text Box, List, Form, and Canvas. Displayables may have commands added to them, which are the equivalent of buttons or menu items on other platforms. Commands can be used to move from one screen to another, or to execute arbitrary Java code. Form Items may be added to Forms, and Choice Elements may be added to Lists or the ChoiceGroup Form Item.