1. © 2005 by Prentice Hall Chapter 12 Designing Interfaces and Dialogues Modern Systems Analysis and Design Fourth Edition Jeffrey A. Hoffer Joey F. George Joseph S. Valacich

2. © 2005 by Prentice Hall 12-2 Learning Objectives 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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4. © 2005 by Prentice Hall 12-4 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

5. © 2005 by Prentice Hall 12-5 A typical interface/dialogue design specification: Similar to form design, but includes multiple forms and dialogue sequence specifications Deliverables and Outcomes

6. © 2005 by Prentice Hall 12-6 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

7. © 2005 by Prentice Hall 12-7 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

8. © 2005 by Prentice Hall 12-8 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

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12. © 2005 by Prentice Hall 12-12 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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14. © 2005 by Prentice Hall 12-14 Good Menu Design

15. © 2005 by Prentice Hall 12-15 Visual editing tools help designers construct menus.

16. © 2005 by Prentice Hall 12-16 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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18. © 2005 by Prentice Hall 12-18 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

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20. © 2005 by Prentice Hall 12-20 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

21. © 2005 by Prentice Hall 12-21 Hardware Options for System Interaction Keyboard Mouse Joystick Trackball Touch Screen Light Pen Graphics Tablet Voice

22. © 2005 by Prentice Hall 12-22 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

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24. © 2005 by Prentice Hall 12-24 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

25. © 2005 by Prentice Hall 12-25 Structuring Data Entry 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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27. © 2005 by Prentice Hall 12-27 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

28. © 2005 by Prentice Hall 12-28 Types of Validation Tests Class or Composition Combinations Expected Values Missing Data Pictures/Templates Range Reasonableness Self-checking Digits Size Values

29. © 2005 by Prentice Hall 12-29 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

30. © 2005 by Prentice Hall 12-30 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

31. © 2005 by Prentice Hall 12-31 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

32. © 2005 by Prentice Hall 12-32 Guidelines for Dialogue Design Consistency Shortcuts and Sequence Feedback Closure Error Handling Reversal Control Ease

33. © 2005 by Prentice Hall 12-33 Dialogue Diagramming A formal method for designing and representing human-computer dialogues using box and line diagrams

34. © 2005 by Prentice Hall 12-34 Dialogue diagrams depict the sequence, conditional branching, and repetition of dialogues.

35. © 2005 by Prentice Hall 12-35 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.

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37. © 2005 by Prentice Hall 12-37 GUI Window Properties That Can Be Turned On or Off Modality: require user to finish action before proceeding Resizable: allow user to change size of window Movable: allow user to reposition window Maximize: allow user to make window take entire screen Minimize: allow user to completely hide window System menu: allow window to have access to system level functions

38. © 2005 by Prentice Hall 12-38 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.

39. © 2005 by Prentice Hall 12-39 Summary In 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.