52 An overview of the system — User interface
Developer’s Guide – RIM 950 Wireless Handheld™
User interface The user can acquire data from the application through the RIM Wireless
Handheld’s LCD. In order to use the LCD, the application mus t make a
request to become the foreground task. For more information on making
an application a foreground task, see the RIM 950 Wireless Handheld OS
API Developer’s Guide. Once the task has become the foreground task, it
can use OS level calls to display data on the LCD or alternatively use
higher-level objects defined by the UI Engine.
The application can acquire data from the user through the keyboard, a
system level device that posts a MESSAGE whenever a key is pressed. The
application can acquire the information by getting that MESSAGE through
RimGetMessage().
A RIM Wireless Handheld user can manually activate an application by
selecting that application’s icon on the main screen. You create such an
icon by registering a name and a bitmap using the
RibbonRegisterApplication() function. The DEVICE_RIBBON will
then post a MESSAGE to the application’s task that can be used to invoke
the appropriate application code. For more information, see the RIM 950
Wireless Handheld Ribbon API Developer’s Guide.
The user can also activate an application manually by selecting its entry
in the Options List. You create such an entry by registering a name and a
callback function using the OptionsEntry() function. T his function
calls the callback function that has access to the LCD (has the
foreground) through the Options thread. This approach should only be
used to make application parameter changes and other changes of a
limited nature.
API overview This section provides an overview of the RIM Wireless Hand held
Application Programming Interfaces (APIs), how they are organized,
and some of the features that can be used in RIM Wireless Handheld
applications.