© 2005 by prentice hall chapter 3c designing interfaces and dialogues
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© 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.
© 2005 by Prentice Hall© 2005 by Prentice Hall12-3
© 2005 by Prentice Hall© 2005 by Prentice Hall12-4
A typical interface/dialogue design specification:
Similar to form design, but includes multiple forms and dialogue sequence specifications
Deliverables and Outcomes
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INTERFACE METHODS
Interface: the method by which a user interacts with the information systemCommon interaction methods Command line Menu Form Object-based Natural language
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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
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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
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Pop-up menu
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© 2005 by Prentice Hall© 2005 by Prentice Hall12-12
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
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Contrasting Menu Designs
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Visual editing tools help designers construct menus.
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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
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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
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© 2005 by Prentice Hall© 2005 by Prentice Hall12-19
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
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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
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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
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Options for Entering Text
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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
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Types of Validation Tests
Class or Composition
Combinations
Expected Values
Missing Data
Pictures/Templates
Range
Reasonableness
Self-checking Digits
Size
Values
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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
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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
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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
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Guidelines for Dialogue Design
Consistency
Shortcuts and Sequence
Feedback
Closure
Error Handling
Reversal
Control
Ease
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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.
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Dialogue diagrams depict the sequence, conditional branching, and repetition of dialogues.
© 2005 by Prentice Hall© 2005 by Prentice Hall12-31
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.
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