Understanding WML Usage

End users of your WML code have several needs that are unique to wireless application development. To develop truly usable applications in WML, an understanding of how these applications are used in the real world is essential.

To develop a great application, you should keep in mind several fundamental things. First and foremost, a great mobile application will be highly usable. Because of the display and interface limitations on most phones and PDAs, users have a more difficult time determining the context of the application and their options. Clarity and brevity are critical in writing text and titles for WML applications to ensure ease-of-use. Furthermore, your application should require minimal text entry for the user. On many phones with as few as 15 buttons, text entry is highly tedious and anything you can do to minimize that burden for your user is beneficial.

Mobile Users

The Wireless Application Protocol was designed to service needs of mobile users that were not served by previous attempts at mobile computing. These users need specific information that is easily accessible with a multifunctional device that meets most of their needs. When you examine mobile devices that have been on the U.S. market for the last five years (including laptops, rugged computers, or wearable computers), they all present problems to everyday users, consumers, and mobile office workers that are solved by WAP and WAP-compliant devices.

What problems with the old devices make WAP-compliant devices so appealing?

• Size and bulk— The older devices are bulky and designed to fulfill a few tasks you would normally do sitting at a desk.

• Power supply— A powerful and large device such as a laptop can race through a battery; therefore, heavy battery packs are necessary.

• Durability— Because of the size of the device, they are prone to fall and get bumped or damaged in transit.

WAP-compliant devices have been designed to alleviate these issues for users to whom they present a barrier. The devices (most typically phones or PDAs) are small and lightweight, require a reasonable power supply, and are sufficiently rugged to handle the environmental demands mobile usage requires. Because WML uses low bandwidth and power, it is ideally suited to deliver mobile applications to users. With that in mind, how can you design your applications to not only meet but exceed your users'needs?

Imagining Your User

Depending on what kind of application you are building, your users and their needs will vary. The best mobile applications serve users'needs based on their priorities—not the developer's. How can you find out what those priorities are? While big companies might be able to conduct focus groups and do research to discover these priorities, individuals developing WAP applications on their own have two courses. One, gain experience as a user and use a phone or emulator to surf existing WAP sites, discovering what works and what doesn't from the user's perspective. Two, use your imagination to create a rounded picture of your users to identify their needs and create a truly relevant mobile application.

For example, instead of developing your coffee-shop locator application for "generic consumer," develop it with several potential users in mind:

"Mr. Rich Bean"—He commutes to work, has a mobile phone for his business and uses it to check his stock quotes. He's got an expensive corporate phone with all the features. He never turns his phone off, except on weekends.

"Sue Burban"—A mother of two who juggles her family's schedule in their SUV, Sue has an inexpensive phone and has it on only while she's shuttling her kids back and forth in the car. Because she's always on the go, Sue likes to use drive-thru services as much as possible.

"Phil DeMugg"—A college student whose parents gave him a medium-class phone. He's mostly interested in going to the local coffee shop between classes to study and meet up with friends. Phil doesn't have a car and stays near campus most of the time.

By keeping specific user needs in mind, the coffee-shop locator can be built around their needs. Maybe for Sue, you can build in a search or sorting component for coffee shops that have drive-thru windows. Maybe Rich would like to know which coffee shops have special offers on his route to work. Perhaps Phil would want to know at which campus coffee shop his friends are hanging out or where he can get the cheapest grande mocha.

With more realistic and specific user profiles, you can develop your applications around the kinds of lifestyles and routines your users have, making your applications much more usable.

Relevant Applications

WML answers most of the usability questions of previous mobile-computing solutions, but WAP makes some assumptions to answer them. Small screen sizes solve several problems, but present a new one: limited displays for your application. Relevant WML applications solve this by succinctly providing critical data through superior navigation and sorting. Alternatively, applications that provide lots of content for browsing will prove tedious for the end user and taxing for the phone's bandwidth, rendering the application all but useless.

In another example, WML's limited offline memory presents a challenge to creating a relevant application. For the majority of existing applications, we assume that you will always have access to the digital cellular network. In Europe and parts of Asia, this assumption is entirely valid. In the United States, some suburban areas and most rural areas lack coverage at present and, therefore, constant connectivity cannot be assumed. Applications in the United States, therefore, must be targeted geographically to be relevant and designed to handle instances where the user will be cut off from the network during usage. This may mean that your applications will need to provide a mechanism for reentering the application at the point at which it was cut off.

To address this issue when developing WML applications, it is important to consider the context as well as the usage of the application. For example, an application requiring constant connectivity in Montana would be problematic because of the offline data storage limitations WML presents in poor coverage areas. However, equipping a company's entire sales force with a sales-tracking application and mobile intranet for a company in Minneapolis or New York would be a much better target application as guaranteed data rates, and connectivity will most certainly exist. Although this problem is expected to be alleviated over time as network coverage increases, you must currently work around it when deploying an application for public usage.

What makes an application a good target for a mobile application? There are four basic questions to ask yourself:

• Does the user need real-time access to important data?

• Can the data be presented in an intuitive way onto a device that has screen limitations?

• Can a small amount of data be transmitted to serve the users'needs?

• Is the user going to have excellent cellular data coverage?

Each question seeks to fit the application into an important mobile model.

The basis of the Wireless Processing Model in Figure 2.6 is that there is a specific user who needs to access specific information. That information will be manipulated so it can be delivered on a small device with limited interface and small screen size. The key to delivering a relevant mobile application is delivering "golden nuggets" of information. What is "golden" depends entirely on the user and context. If a user is looking for a single fact or statistic in an article, it is always better to streamline the transmission and receipts by delivering only that "golden nugget" because of network bandwidth limitations.

After data is processed, the data is then sent to the user. In this particular model the transmission must also contain device requirements.

Device Functionality

Although it's possible that future mobile devices will be designed with better displays and interfaces, most phones currently on the market have limited interfaces. For example, the NeoPoint 1000 has an extraordinarily robust screen compared to other existing WAP phones. It boasts 11 lines of vertical text with 16 characters across the screen in its minimum-sized font, whereas most others support only four to five lines of vertical text.

Although the NeoPoint has a generous display, it offers a keypad that is still rather awkward to use. For example, to type the letter l you would have to push the "5" button on the keypad three times. Additionally, most phones offer only two buttons to navigate menus. One normally functions as a Select button, which leaves one button to interact with on menus. The NeoPoint is a good example of the specific limitations of devices and the lack of output control that WML gives you; all other devices on the market have specific limitations and features that must be dealt with.

Limited data entry is one of the reasons your applications must have an easy-to-use and intuitive interface. Data entry is tedious, and for that reason you must try to limit the amount of data entry required in your applications.

Any data entry task converted into a choice list or dynamic entry is a better course for your application. For example, Figures 2.7 and 2.8 show two different strategies for answering the question "What is your favorite fruit?"

The style in Figure 2.7 uses manual data entry, whereas Figure 2.8 shows a drop-down menu to solve the problem. In this case, our favorite fruit is an apple. In a test we conducted using manual data entry, it took on average about 15 seconds (and nine button presses) to enter the needed data. Remember, that test was conducted with individuals highly accustomed to the data-entry format of WAP phones. For new users it will certainly take longer and cause greater frustration. Using the style shown in Figure 2.8, we needed only two button presses, taking about three seconds total, to answer the question.

WML can be extraordinarily powerful when you are writing applications that connect people. Let's examine how WML can help transform the typically frustrating experience of contacting a customer-service call center into an easy and quick experience. How many of us can tell stories of being lost in a touch-tone jungle? Well, that's because 80% of the information we consciously remember is perceived visually. That's just one reason audio phone trees are so frustrating. WML not only has a visual screen but the power to dial your phone for you, allowing for some interesting possibilities to arise. Imagine if you could punch the call center up on your WAP phone using WML and then visually view the menu choices. When you reach the end of the menu choices, your phone would dial the customer service representative and allow any information you entered on your WML screen to instantly appear on the customer service rep's computer screen to better serve you and save everyone's time!

WAP devices are powerful multifunction devices. The call-center example demonstrates one way these features can be exploited to enhance your applications. The key to developing strong applications is to identify the application's goals and, at the same time, negotiate the device's limitations. Assuming these concepts are well understood, WML is a powerful and easy language that will allow you to easily deploy applications in a mobile environment.