By Tony Patton
Monday, July 17 2006 09:59 AM
URL: http://www.zdnetasia.com/techguide/wireless/0,39044905,39375181,00.htm

In a previous column, I discussed screen resolution and addressed the merits of the standard 800x600 screen size. That amount of screen real estate is unimaginable when you're working with handheld devices such as cell phones and PDAs. In addition to screen size, there are many more design considerations when targeting these smaller platforms. I'll explore these issues in this week's column.

Size does matter
While screen resolution is an issue with regular Web browsing, the actual screen dimensions are important when dealing with mobile devices. Screen size limitations are an issue because the majority of Web sites are designed to be viewed on desktop size displays. Their page layout assumes that users can view large portions of a page at once. The much smaller page excerpts displayed on a handheld device screen interferes with page functionality and user comprehension. The result is that users have to spend an inordinate amount of time awkwardly scrolling up and down as well as left and right.

Content is king
Due to the space limitations, developers should be conscious of the following tips when targeting mobile devices:

• Limit graphics: Graphics are an excellent way to spice up a Web site, but their use is questionable when working with small screens. Also, many handheld devices feature monochrome displays, so rich color graphics are lost. The most important text or information should take center stage. If you must use graphics, limit their size to control download times. In addition, effectively use every pixel of a graphic and avoid unnecessary elements. On a final note, take advantage of the alt tag for images so graphic functionality is conveyed when/if images are not displayed.
• Limit download times: Travel back in time to the initial days of the Web where dial-up connections with a 9,600 baud modem was cutting edge, and you will understand the bandwidth limitations for wireless devices. So, you should develop scaled-down pages that eliminate the bells and whistles and deliver only what is necessary to mobile clients.
• Carefully select content: Tailor the content specifically to the target user group by displaying only the most essential data.
• Minimize page length and size: Scrolling on handheld devices is often limited, awkward, and hard for users to keep track of their place with scroll keys and other pen input devices. With that in mind, you should limit the amount of scrolling required in a Web application. This may involve splitting normal pages into multiple pages for handhelds. Architecting the site for handheld devices demands information that is effectively organized to maximize user experience.
• Utilize standard HTML: Stick with standard HTML tags to ensure proper functioning of an application.

When developing applications for mobile or handheld browsers, your main focus is on the content. The reduced screen size relegates the extra items to the scrap heap. This includes needless graphics, as well as all other nonessential page elements. It forces the design team to clearly define or pinpoint what is most important to the target user group.

Dealing with user input
Another issue you face when interacting with a Web application via a handheld device is user input. A user may type on a miniature keyboard, use buttons for scrolling and selection, or use a pen-based device like the ones found with a Palm device. After all, including an input form is not a good idea when the user has only a few input buttons and no keyboard.

Testing
An important part of every development project is testing, but this can be quite a chore when targeting handheld devices. There are so many devices on the market, it is almost impossible to test with every conceivable application. Most manufacturers provide a Software Development Kit (SDK) to test applications on their platforms. A few notable platforms include Symbian, Palm, Motorola, and the BlackBerry.

Development options
A few years ago, there was a lot of hype around Wireless Markup Language (WML), but it has dissipated as devices now support HTML and CSS. While most mobile devices can easily handle regular HTML pages, there are other options available.

You may opt to develop a mobile application as opposed to a Web application. Mobile applications are actually installed on the device. They run inside the mobile device and use its memory and disk space. The difference between mobile and Web applications is they can run without Internet connectivity.

The .NET Compact Framework and Java ME are two examples of mobile development platforms. They allow you to utilize programming languages to deliver mobile functionality. While they may include Web functionality, they most often do not rely on it.

A whole new set of users
The cell phone market has fueled the explosion of the market for mobile devices. It was only a matter of time before Internet capabilities were extended to these devices. It began with e-mail retrieval and now includes Web browsing. While it is great to have the Web at your fingertips, developing applications for these devices requires a different set of considerations from normal Web applications. The key is focusing on the content and screen size when targeting handhelds.

Tony Patton began his professional career as an application developer earning Java, VB, Lotus, and XML certifications to bolster his knowledge.