Building Usable WAP Applications

Usability

For the purpose of this presentation, we can define usability as follows:

Limitations of Wireless Devices

Let's review the limitations of WAP devices here:

 

Ø       Small screens: In general, WAP devices are tiny. Those accustomed to web browsers will find navigating with a WAP phone a real pain.

Ø       Limited input facilities: Most wireless devices lack a keyboard that is anything like a traditional QWERTY PC keyboard. Simple, mass-market, consumer-class data input technology that does not depend on a keyboard has yet to be invented.

Ø       Limited processor power and memory: WAP browsers are simple and unforgiving.

Ø       Limited bandwidth: At this stage, WAP devices have very little bandwidth available when compared to PCs. In Europe, users can count on a speed of 9600 bps (bits per second) as of April 2000. The introduction of GPRS may improve the situation slightly by the end of 2000.

Ø       Lack of graphics: Or at least, very limited support for them. Icons and graphics can go a long way towards helping the user in complicated situations.

Ø       Limited deck size: A deck can contain only a limited amount of information.

 

These limitations have serious implications for the way you design your WAP application.

WAP Users

WAP users are not sitting in front of a PC. They are on the move, on their way to a meeting, or in a crowded train. Sometimes they're under pressure. Building usable WAP systems is not straightforward, and goal when doing so should be to make it as simple to use as possible. While this is true for any application, it's an absolute must in the context of WAP. WAP users are subject to many distracting events in the environment that surrounds them, and this adds to the input/output limitations of WAP phones described above.

 

In three years, it is estimated that there will be half a billion WAP-enabled mobile phones around. This means that potential WAP users will outnumber conventional Internet users by far. One implication of this is that, in general, you cannot assume that the users of your application are also conventional Internet users.

WML Interoperability Issues

WML delivers content and user interfaces across very different kinds of devices. The various browser implementations render WML in different ways, and this will affect the usability of our applications. This paper will discuss this issue in detail.

 

A usable WAP application should never confuse users, in that users should ideally be able to find the most obvious operations intuitively - just one click away. Unfortunately, if you tweak your application to be more usable on a particular device, the chances are that usability will suffer on other devices.

 

This awkward situation is not simple to solve. In the worst case, implementing multiple versions of an application (one for each family of browsers) might be the best option you have. Learn about usability, and think about what can best be achieved for your specific applications in your specific context.

Different Devices

Fine-tuning usability necessarily implies getting involved with the idiosyncrasies of each device you intend to support. There's a general rule that you should always keep in mind:

If, while developing your applications, you target the smallest devices that you intend to support, you will find that in most cases you automatically target larger devices too. PDA-like devices will be especially well covered, as they support hyperlinks and features handled by <do> elements (features that are problematic on very small screens) very well.

 

At the end of the presentation, I'll focus on two very common microbrowsers: the Nokia 7110 and the UP.Browser family.