Palm OS Programming, 2nd Edition

What to Remember

In this chapter, we have given you a description of important terminology, standards, and a description of how an application interacts with the Palm OS on a device. Most importantly, you should remember the following:

• A Palm application is an event-driven system. The system’s event queue feeds a constant flow of events to your application and it is up to you to handle them.

• Events are fed to four different routines (SysHandleEvent , MenuHandleEvent , AppHandleEvent , FrmDispatchEvent ) in your event loop. Each routine has responsibilities for various events.

• A standard Palm application has a main routine, PilotMain , from which everything is called. We showed you a sample program that contains a typical PilotMain routine that you will use in your own applications.

• There are times, other than when opened by the user, when your application may be called by the system. Launch codes and the various launch flags tell your application how it was called by the system and what is expected.

From all of this information, you should now be well on your way to understanding this application architecture. In the following chapters, you will be using this information to move beyond our simple OReilly Starter application to create a full-featured application.