© 2005 by Prentice Hall Chapter 3c Designing Interfaces and Dialogues

© 2005 by Prentice Hall 12-2 Learning Objectives 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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© 2005 by Prentice Hall 12-4 A typical interface/dialogue design specification: Similar to form design, but includes multiple forms and dialogue sequence specifications Deliverables and Outcomes

© 2005 by Prentice Hall 12-5 INTERFACE METHODS Interface: the method by which a user interacts with the information system Common interaction methods Command line Menu Form Object-based Natural language

© 2005 by Prentice Hall 12-6 Command Line Interaction Users enter explicit statements into a system to invoke operations Example 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

© 2005 by Prentice Hall 12-7 Menu Interaction A list of system options is provided and specific command is invoked by user selection of a menu option Two 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 12-8 Pop-up menu

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© 2005 by Prentice Hall 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

© 2005 by Prentice Hall Contrasting Menu Designs

© 2005 by Prentice Hall Visual editing tools help designers construct menus.

© 2005 by Prentice Hall 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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© 2005 by Prentice Hall 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 Natural Language Interaction Inputs to and outputs from system are in a conventional speaking language like English Based on research in artificial intelligence Current implementations are tedious and difficult to work with, not as viable as other interaction methods Both keyboard and voice entry

© 2005 by Prentice Hall 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

© 2005 by Prentice Hall 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

© 2005 by Prentice Hall Options for Entering Text

© 2005 by Prentice Hall Controlling Data Input Objective: reduce data entry errors Common sources data entry errors in a field: Appending: adding additional characters Truncating: losing characters Transcripting: entering invalid data Transposing: reversing sequence of characters

© 2005 by Prentice Hall Types of Validation Tests Class or Composition Combinations Expected Values Missing Data Pictures/Templates Range Reasonableness Self-checking Digits Size Values

© 2005 by Prentice Hall 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 Providing Help Place yourself in user’s place when designing help Guidelines: 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 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

© 2005 by Prentice Hall Guidelines for Dialogue Design Consistency Shortcuts and Sequence Feedback Closure Error Handling Reversal Control Ease

© 2005 by Prentice Hall Designing the Dialogue Sequence Dialogue diagramming: A formal method for designing and representing human-computer dialogues using box and line diagrams. See Figure for example.

© 2005 by Prentice Hall Dialogue diagrams depict the sequence, conditional branching, and repetition of dialogues.

© 2005 by Prentice Hall Summary In 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.