Datasheet
18
Part I: Getting Started
something done, you’d really like the technology to disappear. The device
itself should become simply an integral part of the environment you’re in.
If you base your application on how the user interacts and thinks about the
world, designing a great user interface becomes a whole lot easier. But that
doesn’t mean there aren’t a significant number of ways to still blow it.
The user interface — form following
function
Don’t underestimate the effect of the user interface on the people who are
trying to use it. A bad user interface can make even a great application pain-
ful to use. If users can’t quickly figure out how to use your application, or if
the user interface is cluttered or obscure, they’re likely to move on and prob-
ably complain loudly about the application to anyone who will listen.
Simplicity and ease of use are fundamental principles for all types of soft-
ware, but in iPhone applications, they are critical. Why? iPhone OS users are
probably in the middle of other things while they use your application.
The iPhone hardware and software are outstanding examples of form follow-
ing function; the user interfaces of great applications follow that principle as
well. In fact, even the iPhone’s limitations (except for battery life) are a result
of form following from the functional requirements of a mobile device user.
Just think how the iPhone fulfills the following mobile device user wish list:
✓ Small footprint
✓ Thin
✓ Lightweight
✓ Self-contained — no need for an external keyboard or mouse
✓ Task-oriented
It’s a pretty safe bet that part of the appeal of the iPhone to many people —
especially to non-technical users (like most of my friends) — is aesthetic:
The device is sleek, compact, and fun to use. But the aesthetics of an iPhone
application aren’t just about how beautiful your application is onscreen. Eye
candy is all well and good, but how well does your user interface match its
function — that is, do its job?
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