Chapter 12 Designing Interfaces and Dialogues

1. Modern Systems Analysisand DesignFourth EditionJeffrey A. Hoffer Joey F. GeorgeJoseph S. Valacich Chapter 12 Designing Interfaces and Dialogues

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.

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. Deliverables and Outcomes A typical interface/dialogue design specification: Similar to form design, but includes multiple forms and dialogue sequence specifications

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. 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. 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

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

14. Good Menu Design

15. Visual editing tools help designers construct menus.

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

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

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. Keyboard Mouse Joystick Trackball Touch Screen Light Pen Graphics Tablet Voice Hardware Options for System Interaction

22. 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 Usability Problems with Hardware Devices

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. Structuring Data Entry

26. Entering Text

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. Class or Composition Combinations Expected Values Missing Data Pictures/Templates Range Reasonableness Self-checking Digits Size Values Types of Validation Tests

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. 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. 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. Consistency Shortcuts and Sequence Feedback Closure Error Handling Reversal Control Ease Guidelines for Dialogue Design

33. Dialogue Diagramming A formal method for designing and representing human-computer dialogues using box and line diagrams

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

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.

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. 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. 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.