© 2005 by prentice hall chapter 3c designing interfaces and dialogues

© 2005 by Prentice Hall© 2005 by Prentice Hall

Chapter 3cDesigning Interfaces and

Dialogues

© 2005 by Prentice Hall© 2005 by Prentice Hall12-2

Learning ObjectivesExplain the process of interface and dialogue

design and the deliverables.Contrast and apply methods for interacting with a

system.Describe guidelines for designing interface layout,

data entry field structure, feedback, and system help.

Design human-computer dialogues and understand how dialogue diagramming can be used.


A typical interface/dialogue design specification:

Similar to form design, but includes multiple forms and dialogue sequence specifications

Deliverables and Outcomes


INTERFACE METHODS

Interface: the method by which a user interacts with the information systemCommon interaction methods Command line Menu Form Object-based Natural language


Command Line Interaction

Users enter explicit statements into a system to invoke operationsExample from MS DOS: COPY C:PAPER.DOC A:PAPER.DOC This copies a file from the C: drive to the A:

drive

Includes keyboard shortcuts and function keys


Menu Interaction

A list of system options is provided and specific command is invoked by user selection of a menu optionTwo common menu types: Pop-up: menu placed near current cursor

position Drop-down: access point to menu placed at top

line of display, menu drops down when access point clicked


Pop-up menu


Guidelines for Menu Design

Wording: meaningful titles, clear command verbs, mixed upper/lower case

Organization: consistent organizing principle

Length: all choices fit within screen length

Selection: consistent, clear and easy selection methods

Highlighting: only for selected options or unavailable options


Contrasting Menu Designs


Visual editing tools help designers construct menus.


Form Interaction

Allows users to fill in the blanks when working with a system

Measures of an effective design: Self-explanatory title and field headings Fields organized into logical groupings Distinctive boundaries Default values Displays appropriate field lengths Minimizes the need to scroll windows


Object Interaction

Symbols are used to represent commands or functions.

Icons: Graphic symbols that look like the processing

option they are meant to represent Use little screen space Can be easily understood by users


Natural Language Interaction

Inputs to and outputs from system are in a conventional speaking language like EnglishBased on research in artificial intelligenceCurrent implementations are tedious and difficult to work with, not as viable as other interaction methodsBoth keyboard and voice entry


DESIGNING INTERFACES

Use standard formats similar to paper-based forms and reports

Left-to-right, top-to-bottom navigation

Flexibility and consistency: Free movement between fields No permanent data storage until the user requests Each key and command assigned to one function


Guidelines for Structuring Data Entry Fields

Entry Never require data that are already online or that can be computed

Defaults Always provide default values when appropriate

Units Make clear the type of data units requested for entry

Replacement Use character replacement when appropriate

Captioning Always place a caption adjacent to fields

Format Provide formatting examples

Justify Automatically justify data entries

Help Provide context-sensitive help when appropriate


Options for Entering Text


Controlling Data Input

Objective: reduce data entry errorsCommon sources data entry errors in a field: Appending: adding additional characters Truncating: losing characters Transcripting: entering invalid data Transposing: reversing sequence of characters


Types of Validation Tests

Class or Composition

Combinations

Expected Values

Missing Data

Pictures/Templates

Range

Reasonableness

Self-checking Digits

Size

Values


Feedback Messages

Status information: keep user informed of what’s going on, helpful when user has to wait for response

Prompting cues: tell user when input is needed, and how to provide the input

Warning or Error: inform user that something is wrong, either with data entry or system operation


Providing Help

Place yourself in user’s place when designing helpGuidelines: Simplicity

Help messages should be short and to the point Organize

Information in help messages should be easily absorbed by users

Show It is useful to explicitly show users how to perform an operation


DESIGNING DIALOGUES

Dialogue: A sequence of interactions between the system and a user

Dialogue design involves: Designing a dialogue sequence Building a prototype Assessing usability


Guidelines for Dialogue Design

Consistency

Shortcuts and Sequence

Feedback

Closure

Error Handling

Reversal

Control

Ease


Designing the Dialogue Sequence

Dialogue diagramming: A formal method for designing and representing human-computer dialogues using box and line diagrams. See Figure 12-19 for example.


Dialogue diagrams depict the sequence, conditional branching, and repetition of dialogues.


SummaryIn this chapter you learned how to: Explain the process of interface and dialogue

design and the deliverables. Contrast and apply methods for interacting with a

system. Describe guidelines for designing interface

layout, data entry field structure, feedback, and system help.

Design human-computer dialogues and understand how dialogue diagramming can be used.

© 2005 by prentice hall chapter 3c designing interfaces and dialogues

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