NAME
Action Message — Reference
Description
An action message is a message displayed in a secondary window
that indicates a condition has occurred that requires a response
from the user. The user can correct the condition and then continue,
withdraw the request, or get help.
There are three kinds of action messages: question messages,
warning messages, and error messages.
- Question messages
Gets a response to a question. Display question
messages when the user's immediate attention is not required, such
as when the user's data will not be lost or deteriorate with time.
- Warning messages
Alerts the user to a possible danger. Display warning
messages to give the user one last chance to retract an operation
that is potentially destructive or reversible only with great difficulty.
- Error messages
Conveys a message about a critical condition user
error. Display error messages when the user's attention is needed
to cancel the text or correct the situation.
An action message suspends the task until the message is removed.
You can display the message window as an application-modal window
if user interaction with the application is to be restricted. At
the very least, you should be careful about allowing any change
of state that would affect the suspended task. Figure 2 “Action Message
Types” illustrates
the types of action messages.
When to Use
- Required
Display a question message when the user must respond
to a question before continuing the task, but only when the task
can be suspended indefinitely without harm and other user activity
is unlikely to affect the continuation of the task at a later time.
- Required
Display a warning message to alert the user to a
possible danger and to allow the user to take some alternative action
or to withdraw the task request.
- Required
Display an error message when a response is needed
before the task can be continued (or if it is likely that other
user actions might make the task impossible to continue) and if
it is essential that either the situation be corrected or the task
canceled.
Guidelines
- Required
Display the appropriate symbol to the left of each
action message as follows (except in cases of bidirectional language
support; see Chapter 11):
- Question message
?
- Warning message
!
- Error message
0
- Recommended
In a warning message, clearly explain the possible
danger that can occur.
- Recommended
In an error message, suggest possible actions that
the user can take to correct the situation that caused the message
to appear. For example:
Entry must be a hexadecimal value between 0 to 9 or A
to F. Correct entry and choose RETRY.
- Recommended
In the text of an error message, indicate the possible
cause of the error.
Behavior
- Required
Display an action message in a secondary window.
- Recommended
Use a system-modal secondary window to display the
message only if the user's immediate attention is required and if
any user actions outside of the message window would make it impossible
to resume the task or render it meaningless.
- Recommended
Use an application-modal secondary window to display
the message if the user can correct the situation without interacting
with the application or must correct the situation by interacting
through the message window.
- Recommended
Use a modeless secondary window to display the message
if the user cannot correct the situation by interacting through
the message window but must interact with the application while
the message remains displayed.
- Recommended
When the user cancels a task, leave the objects
or data in a form that is meaningful to the user. For example, when
the user requests that an object be copied, and an error occurs
that causes the user to cancel the task while the object is being
copied, remove the partially copied object from the target destination.
Providing Controls in an Action Message
- Recommended
Provide controls in the message window that allow
the user to correct the situation that caused the message to appear
or to request a related alternative action. For example, provide
a text-entry field in which the user can correct a value, such as
the name of the printer to use for printing a document.
- Recommended
Provide a Retry push button that allows the user
to continue or retry the task after correcting the situation that
caused the message to appear. In an error message about a paper
jam on the printer, provide a Retry push button that the user can
activate after clearing the jam.
- Recommended
Provide a Cancel push button that allows the user
to withdraw the task.
- Recommended
Provide a Help push button that allows the user
to access the Help information about the task. For example, provide
a push button labeled Help that explains how to unjam the printer.
- Recommended
Provide at least the following choices in a question
message:
Yes and No (or other appropriate set
of answers)
Cancel (optional, use only if all the other choices
perform some action)
- Recommended
Provide the following choices in an error message:
One choice or two choices labeled
Retry and Cancel
Essential Related Topics
For more information, see the Cancel (Action and Choice),
Information Message,
Message, Push Button (Predefined),
and Warning Signal reference
pages.
Supplemental Related Topics
For more information, see Chapter 4.
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