While we’re on the subject of users, here’s another aspect of a compelling
application: direct manipulation and immediate feedback.
✓ Direct manipulation makes people feel more in control. On the desktop,
that meant a keyboard and mouse; on the iPhone, the Multi-Touch
interface serves the same purpose. In fact, using fingers gives a user a
more immediate sense of control; there’s no intermediary (such as a
mouse) between the user and the object on-screen. To make this effect
happen in your application, keep your on-screen objects visible while
the user manipulates them, for example.
✓ Immediate feedback keeps the users engaged. Great applications
respond to every user action with some visible feedback — such as
highlighting list items briefly when users tap them.
Because of the limitations imposed by using fingers, applications need to be
very forgiving. For example, although the iPhone doesn’t pester the user to
confirm every action, it also won’t let the user perform potentially destructive,
non-recoverable actions (such as deleting all contacts or restarting a
game) without asking, “Are you sure?” Your application should also allow the
user to easily stop a task that’s taking too long to complete.
Notice how the iPhone uses animation to provide feedback. (I especially
like the flipping transitions in the Weather Application when I touch the Info
button.) But keep it simple; excessive or pointless animation interferes with
the application flow, reduces performance, and can really annoy the user.
Why Develop iPhone Applications?
Because you can. Because it’s time. And because it’s fun. Developing my
iPhone applications has been the most fun I’ve had in many years (don’t tell
my wife!). Here’s what makes it so much fun (for me, anyway):
✓ iPhone apps are usually bite-sized — small enough to get your head
around. A single developer — or one with a partner and maybe some
graphics support — can do them. You don’t need a 20-person project
with endless procedures and processes and meetings to create something
valuable.
✓ The applications are crisp and clean, focusing on what the user wants
to do at a particular time and/or place. They’re simple but not simplistic.
This makes application design (and subsequent implementation)
much easier — and faster.
✓ The free iPhone Software Development Kit (SDK) makes development
as easy as possible. I reveal its splendors to you throughout this book.
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