Killer iPhone App Development: PT 1

As with the Macintosh, users have a general sense of how applications work
on the iPhone. (The Windows OS has always been a bit less user-friendly, if
you ask a typical Mac user.) One of the early appeals of the Macintosh was
how similarly all the applications worked. So Apple (no fools they) carried
over this similarity into the iPhone as well. The resulting success story suggests
the following word to the wise. . . .
A compelling iPhone user experience usually requires familiar iPhone interface
components offering standard functionality, such as searching and navigating
hierarchical sets of data. Use the iPhone standard behavior, gestures,
and metaphors in standard ways. For example, users tap a button to make
a selection and flick or drag to scroll a long list. iPhone users understand
these gestures because the built-in applications utilize them consistently.
Fortunately, staying consistent is easy to do on the iPhone; the frameworks at
your disposal have that behavior built in. This is not to say that you should
never extend the interface, especially if you’re blazing new trails or creating
a new game. For example, if you are creating a roulette wheel for the iPhone,
why not use a circular gesture to spin the wheel, even if it isn’t a “standard”
gesture?
Making it obvious
Although simplicity is a definite design principle, great applications are also
easily understandable to the target user. If I’m designing a travel application,
it has to be simple enough for even an inexperienced traveler to use. But if I’m
designing an application for foreign-exchange trading, I don’t have to make it
simple enough for someone with no trading experience to understand.
✓ The main function of a good application is immediately apparent and
accessible to the users it’s intended for.
✓ The standard interface components also give cues to the users. Users
know, for example, to touch buttons and select items from table views
(as in the contact application).
✓ You can’t assume that users are so excited about your application that
they are willing to invest lots of time in figuring it out.
Early Macintosh developers were aware of these principles. They knew that
users expected that they could rip off the shrink-wrap, put a floppy disk in
the machine (these were really early Macintosh developers), and do at least
something productive immediately. The technology has changed since then;
user attitudes, by and large, haven’t.