Palm OS Programming, 2nd Edition

Designing the Sales Application

Now you have seen the application in its final form. We have also discussed some of the design decisions that we had to make while creating the various forms and dialog boxes. There were other decisions, however, that occurred even before the intricate details of each form could be decided. Our very first task was to prototype the application.

Clarify the Tasks

Our prototype design was a mock-up of the basic views that we wanted to have in the application. We came up with those views by listing the actions we wanted the user to be able to do and the order and frequency in which we thought they would be used. Our strategy was to optimize the application so that the more frequent the action, the fewer steps it took to complete. We also wanted to emulate the design of the built-in applications wherever possible.

The Start Screen

The first and most important view to create is the start screen—what your user sees when the application is launched. In the Sales application, the place to start seemed straightforward—with a list of the salesperson’s customers. This is a list that can be modified on the handheld, but would ordinarily be created on the desktop. The desktop application should be clever about culling customers from the list if the salesperson isn’t visiting them on this trip. It might also want to display the customers either alphabetically or by visit (as the salesperson prefers).

Design Trade-offs in the Sample Application

As with any design, we ...