CHAPTER 1
Newton and Its Users
Observe Basic Human Interface Principles 1-7
Feedback 1
In addition to seeing the results of their actions, users need immediate feed-
back when they operate controls and ongoing status reports during lengthy
operations. Have your application respond to every user action with some
visible change. For example, make sure every button highlights when a user
taps it. Audible feedback also helps, but can’t be the primary or sole feedback
because people may use Newtons in places where they can’t hear or where
they must turn off the sound.
The system automatically provides feedback when it’s temporarily busy by
displaying the busy cursor. During operations that last more than a few
seconds, your application should display explanatory messages and show
elapsing progress.
See and Point 1
A Newton application is better than a person at remembering lists of options,
commands, data, and so on. Take advantage of this situation by presenting
lists and letting users choose from them. People can concentrate on
accomplishing tasks with your program instead of remembering how to
operate it. As a bonus, your program controls its inputs and doesn’t have to
check as many error conditions.
Consistency 1
It’s likely that people will use other Newton software besides yours—at the
least they will use some of the built-in applications and services. You can
turn this likelihood to your advantage by designing your application’s inter-
face to be consistent with other Newton applications. Both you and your
application’s users benefit if they can build on prior experience when learning
how to use your application.