Lecture05 Ui

7/28/2019 Lecture05 Ui

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CMPS115 Class 6 : User Interface Design

Due today Scenarios Decomposing paper

Next class Deliverable: Requirements

look at template and at example at link in deliverable webpage

Introduction to Software Architecture by Garlan and Shaw(read and review only pages 1-16)
http://www.cs.cmu.edu/afs/cs/project/vit/ftp/pdf/intro_softarch.pdf


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User Interface Design Principles ideas for this and followingslides from Pressmans Software Engineering, 6/e 2005

Put the user in control Keep the users memory load controlled

Consider issues of consistency


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User Quote (user in control)

What I really would like is a system thatreads my mind.

It knows what I want to do before I needto do it and makes it very easy for me to

get it done.

Thats all, just that.


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Control

Whos in Control? Does user adapt to computers model of task?

Does computer adapt to users model of task? Consider the novice user

Consider the knowledgeable, intermittent user Consider the knowledgeable, frequent user


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User maintains control when:

Youve provided for flexible interaction Youve allowed for interaction to be interrupted andundoable

Youve allowed for interface to be customized tousers skill level

Youve hidden technical internals (no OS commandsneeded)

You dont force user into unnecessary actions Youve designed for direct interaction with objects on

the screen


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Users memory load

Make UI show state with visual cues Use meaningful defaults that can be reset/set

Provide meaningful shortcuts

Make visual layout reflect real world task


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Consistency

Use the same design standard throughout allscreens

Use the same input techniques throughout allscreens


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UI analysis and design

Model the user, task, and environment Design the interface Construct the interface Validate the interface

Iterate through these, with each pass

elaborate additional requirements andresulting design


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User analysis

Interview the users or representatives of theusers

Interview sales, marketing, or support staffabout user characteristics


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Ask questions to understand the users

Trained professionals, technicians, clerical, manufacturing users? Level of education Learn from written materials or is class needed? Expert typists or phobic Age range

One gender predominates? Compensation for users for their work is how? Use during normal work hours or until job is done? Integral part of job or infrequent use? What is primary language of users?

What are consequences of mistakes? Are users subject matter experts? Knowledge about underlying technology needed?


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Environment analysis

What will be the physical location of the sw? Will user be sitting, standing, walking?

Will user be dedicated to this task/multi-

users required for this task? Will there be noise, light, or spaceimpairments?


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Task analysis

What tasks will be done while user is working? What work is performed in special

circumstances?

What special domains are used during work? What is the sequence of workflow?


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Using use cases - identify tasks and subtasksExample - computer-aided design for interior design

Tasks Furniture layout

Fabric selection

Wall/widow coverings sel.

Presentation to user

Costing

Shopping

Subtasks for furn. layout Floor plan drawing givenroom dimensions

Locate windows and doors

Scaled drawings of furn.

Move furniture aroundfloor plan

Provide 3-D view of floorplan with furniture foruser


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Objects derived from use cases

Select physical objects from use casenarratives

Categorize into classes

Define details of the attributes of each class

Determine operations on each of theseobjects


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Task workflow analysis

When different user groups and user roles are to usesoftware Use flow diagram called swimlane diagram Column for each role Bubbles for processes, flows for data Flows between columns represent interactions

between processes of different roles Look and feel of UI for different roles may be

different


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Analysis for presentation of content

Content may be from Other parts of the application Database accessible from application External to application

Format of content

Consistent location for same types? Customizable location? Identification of content? Handling of large datasets? Summary available? Color?

Error handling?


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Steps for UI design

Parse use cases - objects (nouns) andoperations (verbs)

Sketch set of screens

Test UI

Iterate last 2 steps


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Common design issues

Response time Help

Error handling

Command and menu labeling

Consider accessibility for special needs - wwwconsortium Web Content Accessibility Guidelines

Internationalization guidelines are available -

www-306.ibm.com/able/access_ibm/disability.html


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responsiveness

Length of response time 1 sec acceptable

More than that - use progress bar and busy icon

Variability 1 sec is better than from 0.2 sec to 3.0 sec


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Design of help features

Provided for all features or just subset? Available at all times?

How to request?

How presented? Window, print doc, 2-lines How to return to normal operations?

How is help info structured? Flat,hierarchical, hypertext


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Command and menu labels

Easy to remember labels? How to remind? What is form of commands? Control seq or

typed word?

Will all menu items have commands?

Customizable and shortcuts available?

Self-explanatory labels

Do submenu items fit logically under menuitems?


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Test the UI

Review material from M. Rettigs paperPrototyping For Tiny Fingers


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Summary

Weak UI may cause failure of acceptance of system Follow 3 principles of UI design

User in control

Reduce memory load

Consistency Development involves Analysis (user, task, environment)

Design (use cases drive sketches)

Evaluate and iterate


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Bjarne Stronstrup (designer and implementor of C++)

I have always wished that my computerwould be as easy to use as my telephone.

My wish has come true.

I no longer know how to use mytelephone.


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Client/Server Responsiveness Design project issues

Local/Remote awareness Server may balk; client should keep running smoothly Optimistic response (correct if server updates otherwise)

Threading User thread services UI

collects events, changes control state, posts events

not to be used for game action!

Game thread runs engine calculates local world based on local events and server data

I/O thread handles network

Lecture05 Ui

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