13-1 © Prentice Hall, 2004

Chapter 13:Chapter 13:Designing the Human Designing the Human

InterfaceInterface(Adapted)(Adapted)

Object-Oriented Systems Analysis and Design

Joey F. George, Dinesh Batra,

Joseph S. Valacich, Jeffrey A. Hoffer

13-2Chapter 13 © Prentice Hall, 2004

Chapter ObjectivesChapter Objectives

- Concept of User interface– Forms and reports– General guidelines for forms and reports– Dialogue design– Usability Testing; Web Usability

13-3Chapter 13 © Prentice Hall, 2004

Note: In OO Development, user interface is designedin cycles.

13-4Chapter 13 © Prentice Hall, 2004

• UI refers to all the screens through which User provides input to the system and gets output from the system.

• Forms and reports are types of UI supporting access to databases.

- Very common since databases part of almost any system.

- BUT, not only type of UI!!! (book’s bias)

Concept of User Interface (UI)Concept of User Interface (UI)

13-5Chapter 13 © Prentice Hall, 2004

FormForm

- Input and output object

- Input form object: A business document that contains some predefined data and may include some areas where additional data are to be filled in

- Typically based on a database record or query

13-6Chapter 13 © Prentice Hall, 2004

ReportReport

A business document that contains only predefined data

A passive document meant only for reading or viewing, not data input

Typically contains data from many unrelated transactions or records

13-7Chapter 13 © Prentice Hall, 2004

Visual Basic and other development tools provide computer-aided GUI form and report generation.

13-8Chapter 13 © Prentice Hall, 2004

A typical form design specification:

Based on a use case connection – Boundary Class

Involves three parts:

1) Narrative overview2) Sample design3) Assessment

13-9Chapter 13 © Prentice Hall, 2004

13-10Chapter 13 © Prentice Hall, 2004

13-11Chapter 13 © Prentice Hall, 2004

13-12Chapter 13 © Prentice Hall, 2004

Grouping, organization, layout, and highlighting are important considerations in form design

13-13Chapter 13 © Prentice Hall, 2004

Highlighting can include use of upper case, font size differences, bold, italics, underline, boxing, and other approaches.

13-14Chapter 13 © Prentice Hall, 2004

13-15Chapter 13 © Prentice Hall, 2004

Business reports are static, no user interaction. Therefore, business reports are often printed in hardcopy form.

13-16Chapter 13 © Prentice Hall, 2004

13-17Chapter 13 © Prentice Hall, 2004

Bar and line graphs give pictorial summary information that can enhance reports and graphs.

13-18Chapter 13 © Prentice Hall, 2004

Dialogue DesignDialogue Design

– Layout (of widgets, text, and table data)– Structuring data entry (tab order)– Controlling data input (validation and format controls)– Systems’ Feedback (prompting, status, warning, and

error messages)– Dialogue sequencing

Dialogue - A sequence of interactions between the system and a user. Design includes:

13-19Chapter 13 © Prentice Hall, 2004

A typical interface/dialogue design specification:

Similar to form design, but includes multiple forms and dialogue sequence specifications

13-20Chapter 13 © Prentice Hall, 2004

Data entry structure is concerned with navigation flow.

13-21Chapter 13 © Prentice Hall, 2004

Navigation flow should be natural and intuitive to the user, not disjointed and confusing.

13-22Chapter 13 © Prentice Hall, 2004

Also a guideline for UI: Never make slidelike this – for number of lines use 7 +/- rule!

13-23Chapter 13 © Prentice Hall, 2004

System’s Feedback System’s Feedback

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 – informs user that something is wrong, either with data entry or system operation

13-24Chapter 13 © Prentice Hall, 2004

Guidelines for Dialogue DesignGuidelines for Dialogue Design

– Consistency

– Allow sequence, shortcuts, and reversals in navigation

– Frequent feedback

– Logical grouping and sequencing of diagrams, with beginning, middle, and end

– Comprehensive error handling

– Maximize ease and control of use

13-25Chapter 13 © Prentice Hall, 2004

Dialogue sequencing

13-26Chapter 13 © Prentice Hall, 2004

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