Computer Network Router User Manual

CHAPTER 6
Data Input
6-38 Error Handling
When a user initiates an action that can’t be undone and could be very
difficult to reverse by hand, your application should warn the user and give
the user a chance to cancel the action. For example, if a user is about to
change a lot of text with a search-and-replace operation that can’t be undone,
display a confirmation slip that says something to the effect of, “OK to make
this change? (Can’t undo).”
Error Detection 6
Users may notice and correct some input errors, but your application should
also check input items for validity. There are a couple of approaches you can
take to error checking, depending on the circumstances and users’
expectations.
One approach is to check an input item for errors as soon as a user moves
on to another input item. With this approach, a user must correct an error
before the input gets stale or leads to other input errors. However, a user
who makes lots of mistakes may feel pestered by what seem to be nitpicking
error messages.
Another approach is to check all input items in one view at the same time,
when a user taps a button to confirm all the input items and close the view.
This approach only disrupts the user once per view instead of once per input
item. If you take this approach, try to make your error messages as specific
and diagnostic as possible. It’s all too easy to make error messages vague.