Wednesday, March 26, 2008

Common sense tips for developing usable mobile apps

Tips for cell phone design ...

"Cell phones can be much more difficult to use than they should be. Sure, it is easy to blame the users. After all, we are talking about a simple cross pad for selections and paging, a central OK button, a Clear button that backs out, and two shoulder buttons for secondary selections. This is a total of five keys and a full scale of eight button pushes to work a cell phone.

Although, despite the relative lack of input options and the fairly obvious (and consistent) mapping of on-screen displays to the buttons, many people are baffled about how to use their cell phones. We can conclude that either: A huge percentage of the population are total morons who have no business operating anything more difficult than a spoon; or, even the most relatively simple device’s ability to present UI metaphors to the user that make sense are simply not good enough. Since the prospect of a world filled with people so blindingly dumb truly scares me (particularly since so many of them talk on their cell phone while driving), I am going with the latter option.

... Mobile usability challenges

There are a lot of roadblocks to mobile usability. Some of these are hardware issues, which may be impossible to resolve while maintaining the form factor; some of the hardware issues can be entirely or partially handled by more awareness on the part of software developers.

Here are the major challenges to mobile usability:

* Font size: Most phones have fonts that are too small to be read by those with less-than-decent eyesight, and there are no screen readers.
* Button function indication: I believe this issue (which I discuss in the previous section) is the #1 or #2 biggest challenge.
* Poor defaults: A good example is the cell phone’s “assumes” that the user wants to manually input a number; it forces the user to jump through menus to access their contacts; in reality, the default display on a cell phone should be the Contacts list, since that is what people use the vast majority of the time.
* Resolution: For non-cell devices (i.e., UMPCs and smartphones), the resolution is getting close to what desktop PCs used circa 1998 (800 x 600) if it is not already there. The problem is, those desktop PCs had 15″ monitors, not 3″ LCD screens. Programmers have the temptation to stuff a lot of functionality into all of those pixels.

... Basic usability guidelines

Let’s take another look at the challenges, along with a list of basic mobile usability guidelines:

* Font size: From a usability standpoint, it is nearly impossible to make the font too big; the problem is, the screens are too small to make the letters big enough. Make the letters as large as you think you can get away with.
* Button function indication: If the user can start your application, they probably understand their device’s paradigms enough to let this one be a wash. Make sure that your button indicators are clear and will make sense to your audience.
* Defaults: Watch your users closely in “field studies” and look for repetitive behavior. For example, if you observe that cell phone users almost always activate the phone and then go to their Contacts list, you just found your default behavior for what should happen when the phone is activated.
* Resolution: This is hard to handle since you do not know what the resolution will be upfront. In general, put less information on the screen and make it bigger."    (Continued via TechRepublic)    [Usability Resources]

Samsung Cell Phone Display - Usability, User Interface Design

Samsung Cell Phone Display


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