Chapter 7: Getting Input From Users

Tidwell Course NotesCS 275 Page 1

Chapter 7: Getting Input From UsersDesigning interactive forms, in which the user

is expected to supply information required by the application, is particularly challenging.• The meaning and purpose of queries must be clear.

• Unnecessary or redundant questions must be avoided.• Reliance on user memory is a huge mistake.

• What’s easy for the designer may not be easy for the user.


Binary Control OptionsWhen giving the user a choice between two alternatives, there are several control options.


N-Choice Control Options (Small N)There are several control options for making a choice between several alternatives.


N-Choice Control Options (Large N)The alternatives are more limited for controls presenting the user with a long list of items from which to choose.


Multiple-Selection Control OptionsThe interface becomes more confusing when

the user is allowed to make multiple selections.


Text Entry Control OptionsAt times, the application must rely on the user’s memory, spelling, grammar, etc., and request text entry.


Numerical Entry Control OptionsSpecial control mechanisms have been

developed for numerical entry by the user.


Pattern #68: Forgiving FormatWhen there are multiple common input formats,

accommodate user preferences by having the interface handle as many as possible.

Example: In this Alarm Clock

example, the user may use “military” time or traditional AM/PM time to set

the alarm.

Execute


Pattern #69: Structured FormatStructure the format of the input form to correspond to

the format of the input data.

Example: This on-line account form is typical for

structured formats, with simple textboxes for most

input and no error checking performed until the entire

form is submitted.The only potential

improvements would have been a more structured

approach to the zip code and phone number entries.


Pattern #70: Fill-In-The-BlanksWhen user input cannot easily be presented in the

standard label/control format, it is sometimes possible to present it as a simple fill-in-the-blank.

Example: Microsoft Excel allows the user to “goal seek”, i.e. to set one spreadsheet cell’s value to a specific goal by altering a related cell’s value to achieve that goal.


Pattern #71: Input HintsInclude an explanatory comment next to an input field that might not have clear functionality.

Example: Microsoft Word’s “Find and Replace” form allows

the user to jump forwards or backwards a specific number of units (pages, lines, tables, etc.),

but the format for such jumps might require additional

explanation.Note that the explanation is not

included when the jump involves named units like

bookmarks


Pattern #72: Input PromptRather than leaving a text entry field blank, fill it with a prompt that indicates what the user is expected to enter.

Example: When inserting headers and footers into

Microsoft Word documents, input prompts are provided that temporarily detach the

user from the WYSIWYG aspect of the interface (i.e., the header and footer entry

controls will not appear when the actual document is

printed).


Pattern #73: AutocompletionWhen the user begins to input text that has a clear

value, it is sometimes helpful to automatically complete that value’s entry.

Example: Microsoft Excel helpfully auto-completes a field with a value corresponding to one it’s already seen in this column.

Example: Microsoft Word cannot use

context to determine that the word being

attempted is “Febreze”, not

“February”.


Pattern #74: Dropdown ChooserJust as dropdown lists conserve screen space when

employed for menus or combo boxes, the dropdown paradigm may be used for additional modes of user input.

Example: Microsoft Word

uses this approach for

such activities as inserting

tables, formatting

columns, setting toolbar options,

and selecting colors.


Pattern #75: Illustrated ChoicesWhen presenting the user with a selection of choices,

whenever possible, use images rather than simple text.

Example: In Microsoft Word

and PowerPoint, requests to insert

more graphical objects results in

a display of the graphical options.


Pattern #76: List BuilderWhen the user is being asked to create a list from another larger list, provide a mechanism for easily moving elements between the lists.

Example: Two solutions to a Cafeteria application, one using add/remove buttons to create the day’s menu, and the other relying on a checked treeview.


Pattern #77: Good DefaultsPrefill entry fills with default values (if good ones exist) to reduce user labor or to provide examples of acceptable input values.Example:

Microsoft PowerPoint doesn’t provide a mechanism for setting default values for print commands, relying on default values that might be quite different from a user’s regular choices.


Pattern #78: Same-Page Error MessagesRather than generating a modal dialog box to notify the

user of an error, indicate the error on the form currently in use, at a location on the page close to where the erroneous information resides.

Example: When the user attempts an improper

arithmetic command (like dividing by zero or taking

the square root of a negative number),

Microsoft Calculator displays the error in its

output textbox rather than on a separate form.

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Chapter 7: Getting Input From Users