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Fundamentals Guide
Trackwheel
BlackBerry® devices that precede the BlackBerry® Pearl™ 8100 Series do not include a trackball. Instead, they include a trackwheel
on the right side of the device. The trackwheel is the primary control for user navigation.
Users can
•
roll the trackwheel to move the cursor vertically
•
roll the trackwheel while pressing the Alt key to move the cursor horizontally
•
click the trackwheel to select objects or open the menu
Guidelines
•
Familiarize yourself with both the trackwheel and trackball navigation models, and verify that your application works well
for both.
Creating a UI that is consistent with standard BlackBerry UIs
You can use standard MIDP APIs and BlackBerry® UI APIs to create BlackBerry® Java Application UIs.
The BlackBerry UI APIs are a library of UI components that are designed to provide default layouts and behaviors that are
consistent with the core BlackBerry device applications.
•
Screen components provide a standard screen layout, a default menu, and a standard behavior when the BlackBerry device
user presses the Escape key or clicks the trackwheel or trackball.
•
Field components provide standard UI elements for date selection, options, check boxes, lists, text fields and labels, and
progress bar controls.
•
Layout managers provide an application with the ability to arrange components on a BlackBerry device screen in standard
ways, such as horizontally, vertically, or in a left-to-right flow.
You can use the BlackBerry UI APIs to create UIs that include tables, grids, and other specialized features. The BlackBerry Java
Development Environment uses a standard Java event model to receive and respond to specific types of events. Applications can
receive and respond to BlackBerry device user events, such as when the BlackBerry device user clicks the trackwheel, clicks the
trackball, or types on the keyboard, and to system events, such as global alerts, real-time clock changes, and USB port connections.
Creating a UI that is consistent with standard BlackBerry UIs
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