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Modern Systems Analysis and Design Fourth Edition Jeffrey A. Hoffer Joey F. George Joseph S. Valacich. Chapter 12 Designing Interfaces and Dialogues. Learning Objectives. Explain the process of interface and dialogue design. Contrast and apply methods for interacting with a system. - PowerPoint PPT Presentation
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© 2005 by Prentice Hall© 2005 by Prentice Hall
Chapter 12 Designing Interfaces and
Dialogues
Modern Systems Analysisand Design
Fourth Edition
Jeffrey A. Hoffer Joey F. George
Joseph S. Valacich
© 2005 by Prentice Hall© 2005 by Prentice Hall12-2
Learning ObjectivesExplain the process of interface and dialogue
design.Contrast and apply methods for interacting
with a system.List and describe various input devices and
factors affecting their usability.Describe guidelines for designing interface
layout, data entry field structure, feedback, and system help.
Design graphical user interfaces.
© 2005 by Prentice Hall© 2005 by Prentice Hall12-3
© 2005 by Prentice Hall© 2005 by Prentice Hall12-4
Interface/Dialogue Design
Layout (of widgets, text, and table data) Structuring data entry (tab order) Controlling data input (validation and
format controls) Feedback (prompting, status, warning,
and error messages) Dialogue sequencing
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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:
driveIncludes keyboard shortcuts and function keys
© 2005 by Prentice Hall© 2005 by Prentice Hall12-8
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
© 2005 by Prentice Hall© 2005 by Prentice Hall12-9
© 2005 by Prentice Hall© 2005 by Prentice Hall12-10
© 2005 by Prentice Hall© 2005 by Prentice Hall12-11
© 2005 by Prentice Hall© 2005 by Prentice Hall12-12
Guidelines for Menu Design
Wording: meaningful titles, clear command verbs, mixed upper/lower caseOrganization: consistent organizing principleLength: all choices fit within screen lengthSelection: consistent, clear and easy selection methodsHighlighting: only for selected options or unavailable options
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© 2005 by Prentice Hall© 2005 by Prentice Hall12-14
Good Menu Design
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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 systemMeasures 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
© 2005 by Prentice Hall© 2005 by Prentice Hall12-17
© 2005 by Prentice Hall© 2005 by Prentice Hall12-18
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
© 2005 by Prentice Hall© 2005 by Prentice Hall12-19
© 2005 by Prentice Hall© 2005 by Prentice Hall12-20
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 methods
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Hardware Options for System Interaction
KeyboardMouseJoystickTrackball
Touch ScreenLight PenGraphics TabletVoice
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Usability Problems with Hardware Devices
Visual Blocking touch screen, light pen
User Fatigue touch screen, light pen
Movement Scaling keyboard, mouse, joystick,
trackball, graphics tablet, voice
Durability trackball, touch screen
Adequate Feedback keyboard, mouse,
joystick, trackball, graphics tablet, voice
Speed keyboard
Pointing Accuracy joystick, touch screen,
light pen, voice
© 2005 by Prentice Hall© 2005 by Prentice Hall12-23
© 2005 by Prentice Hall© 2005 by Prentice Hall12-24
Designing Interfaces
Use standard formats similar to paper-based forms and reportsLeft-to-right, top-to-bottom navigationFlexibility 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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Structuring Data EntryEntry 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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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 CompositionCombinationsExpected ValuesMissing DataPictures/Templates
RangeReasonablenessSelf-checking DigitsSizeValues
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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
© 2005 by Prentice Hall© 2005 by Prentice Hall12-30
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
© 2005 by Prentice Hall© 2005 by Prentice Hall12-31
What is a Dialogue?
A sequence of interactions between the system and a user
Dialogue design involves: Designing a dialogue sequence Building a prototype Assessing usability
© 2005 by Prentice Hall© 2005 by Prentice Hall12-32
Guidelines for Dialogue Design
ConsistencyShortcuts and SequenceFeedbackClosure
Error HandlingReversalControlEase
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Dialogue DiagrammingA formal method for designing and representing human-computer dialogues using box and line diagrams
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Dialogue diagrams depict the sequence, conditional branching, and repetition of dialogues.
© 2005 by Prentice Hall© 2005 by Prentice Hall12-35
Designing Interfaces and Dialogues in Graphical Environments
Become an expert user of the GUI environment. Understand how other applications have
been designed. Understand standards.
Gain an understanding of the available resources and how they can be used. Become familiar with standards for menus
and forms.
© 2005 by Prentice Hall© 2005 by Prentice Hall12-36
© 2005 by Prentice Hall© 2005 by Prentice Hall12-37
GUI Window Properties That Can Be Turned On or Off
Modality: require user to finish action before proceedingResizable: allow user to change size of windowMovable: allow user to reposition windowMaximize: allow user to make window take entire screenMinimize: allow user to completely hide windowSystem menu: allow window to have access to system level functions
© 2005 by Prentice Hall© 2005 by Prentice Hall12-38
GUI Dialogue Design Issues
Goal is to establish the sequence of displays that users will encounter when working with system.Ability of some GUI environments to jump from application to application or screen to screen makes sequencing a challenge.One approach is to make users always resolve requests for information before proceeding.Dialogue diagramming helps analysts better manage the complexity of designing graphical interfaces.
© 2005 by Prentice Hall© 2005 by Prentice Hall12-39
SummaryIn this chapter you learned how to: Explain the process of interface and dialogue
design. Contrast and apply methods for interacting
with a system. List and describe various input devices and
factors affecting their usability. Describe guidelines for designing interface
layout, data entry field structure, feedback, and system help.
Design graphical user interfaces.
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