This book describes how to design applications for Palm Powered™ handhelds so that they conform to Palm, Inc's user interface guidelines. Read it if you are an application designer or a developer and you are considering creating applications that run on Palm OS®.
Why Follow Guidelines?
Users have come to know and love their Palm Powered handhelds. They expect the applications that run on them to look a certain way and behave a certain way.
Follow the guidelines presented in this book, and your application will look and feel like other Palm OS applications. Users will learn it more quickly, and you'll be well on your way to creating an application that they love and recommend to their friends and colleagues. As a bonus, you'll be able to focus on creating and improving the application itself because documentation requirements and calls to technical support are reduced if the application works the way users expect it to work.
Ignore the guidelines, and you invite user frustration and confusion. Your users may adapt to your application eventually, but you run the risk of alienating a customer base. Sales can suffer.
At the same time, guidelines are not hard and fast rules. A guideline can be broken, but you should do so only after you know why it is there, you have considered all factors involved, and you believe that breaking the guideline is more beneficial to your users than following it would be.
Designing a proper user interface may feel at first like you are "wasting" a lot of time agonizing over the user interface rather than focusing on the nuts and bolts of your application. While most developers acknowledge the importance of user interface design, it's easy to let design take a back seat until the application is working properly. If you do take the time to get the interface right, however, you'll achieve greater success in the long run.
Consider as a case study the success the Palm Powered handheld has had compared its major competitor, the Pocket PC handheld. The Palm Powered handheld was not the first handheld on the market, but it was the first one to be successful because it focused on giving users what they wanted. Palm OS was designed from the ground up with users in mind. Designers focused on what users would want to do with a handheld and provided just that functionality. Palm, Inc. adds more features only when they can do so without diminishing the overall user experience.
In contrast, the first versions of the Windows Pocket PC operating system were designed by stuffing as many features of a desktop Windows system as possible into a pocket-sized form factor. The resulting user experience has been so negative that it has forced the designers back to the drawing board more than once.
Windows Pocket PC handhelds have been on the market for more than three years. Only recently have those devices begun to gain acceptance. In the meantime, 17.5 million Palm Powered handhelds have been sold compared to 2 million Pocket PC handhelds (see Figure 1).
Figure 1 Sales of Palm Powered vs. Pocket PC handhelds

You can see that if you design your interface right the first time, you get a big head start.
How This Book Is Organized
This book is organized as follows:
- Chapter 1 describes the basic principles behind the Palm user interface guidelines, and it describes the design process used at Palm, Inc. Read it to get a good grounding in Palm interface design that prepares you for the chapters that follow.
- Chapter 2 tells you how to design an application so that it fits in well with other Palm OS applications.
- Chapter 3 through Chapter 8 help you with user interface element selection.
Each chapter describes a group of elements that have a common purpose: displaying data, entering commands, and so on. The first section in each chapter describes how to determine which of the elements in the chapter is best for your situation.
The remaining sections give appearance and behavior guidelines specific to each element. Within those sections, you'll find specific display recommendations, descriptions of the behavior Palm OS supplies for the element, and descriptions of the behavior your code must provide.
Because user interface design is not an exact science, many sections end with examples of when to break the rules.
- Appendix A lists the ten most important things to remember about Palm OS application design.
What This Book Does Not Cover
This book focuses solely on design. It does not provide instructions on how to use a development environment to create user interface resources, and it does not discuss which API calls to use to produce a desired behavior from a user interface element.
Augment the information in this book with the following:
- The Palm OS Programmer's Companion, which provides conceptual and task-based information for developers
- The Palm OS Programmer's API Reference, which contains reference material for Palm OS developers
- Documentation for the development environment of your choice
Additional Resources
- Documentation
Palm publishes its latest versions of this and other documents for Palm OS developers at
- Training
Palm and its partners host training classes for Palm OS developers. For topics and schedules, check
- Knowledge Base
The Knowledge Base is a fast, web-based database of technical information. Search for frequently asked questions (FAQs), sample code, white papers, and the development documentation at