14 Chapter 11: Designing the User Interface

14 Systems Analysis and Design in a Changing World, 3rd Edition 2 Identifying and Classifying Inputs and Outputs u Identified by analyst when defining system scope u Requirements model produced during analysis l Event table includes trigger to each external event l Triggers represent inputs l Outputs are shown as responses to events

14 Systems Analysis and Design in a Changing World, 3rd Edition 3 Traditional and OO Approaches to Inputs and Outputs u Traditional approach to inputs and outputs l Shown as data flows on context diagram, data flow diagram (DFD) fragments, and detailed DFDs u OO approach to inputs and outputs l Defined by message entering or leaving system l Included in event table as triggers and responses l Actors provide inputs for many use cases l Use cases provide outputs to actors

14 Systems Analysis and Design in a Changing World, 3rd Edition 4 User versus System Interface u System interfaces: I/O requiring minimal human interaction u User interfaces: l I/O requiring human interaction l User interface is everything end user comes into contact with while using the system l To the user, the interface is the system u Analyst designs system interfaces separate from user interfaces u Requires different expertise and technology

14 Systems Analysis and Design in a Changing World, 3rd Edition 5 Understanding the User Interface u Physical Aspects of the User Interface l Devices touched by user- keyboard, mouse, touch screen, Physical parts- manuals, documentation, and forms u Perceptual Aspects of the User Interface l Everything else user sees, hears, or touches such as screen objects, menus, and buttons u Conceptual Aspects of the User Interface l What user knows about system and logical function of system

14 Systems Analysis and Design in a Changing World, 3rd Edition 6 Aspects of the User Interface

14 Systems Analysis and Design in a Changing World, 3rd Edition 7 Guidelines for Designing User Interfaces u Visibility l All controls should be visible l Provide immediate feedback to indicate control is responding l Example: Button make sound / change look when it is clicked. u Affordance l Appearance of control should suggest its functionality – purpose for which it is used l Example: Steering button used to turn.

14 Systems Analysis and Design in a Changing World, 3rd Edition 8 Documenting Dialog Designs u Done simultaneously with other system activities u Based on inputs and outputs requiring user interaction u Used to define menu hierarchy l Allows user to navigate to each dialog l Provides overall system structure u Storyboards, prototypes, and UML diagrams

14 Systems Analysis and Design in a Changing World, 3rd Edition 9 Overall Menu Hierarchy Design

14 Systems Analysis and Design in a Changing World, 3rd Edition 10 Dialogs and Storyboards u Many methods exist for documenting dialogs l Written descriptions following flow of events l Narratives l Sketches of screens l Storyboarding – showing sequence of sketches of display screen during a dialog

14 Systems Analysis and Design in a Changing World, 3rd Edition 11 Storyboard for Downtown Videos

14 Systems Analysis and Design in a Changing World, 3rd Edition 12 Guidelines for Designing Windows and Browser Forms u Each dialog might require several window forms u Standard forms are widely available l Windows: Visual Basic, C++, Java l Browser: HTML, VB-Script, JavaScript, ASP or Java servlets u Implementation l Identify objectives of form and associated data fields l Construct form with prototyping tools

14 Systems Analysis and Design in a Changing World, 3rd Edition 13 Forms Design Issues u Form layout and formatting consistency l Headings, labels, logos l Font sizes, highlighting, colors l Order of data-entry fields and buttons u Data keying and data entry (use standard control) l Text boxes, list boxes, combo boxes, etc. u Navigation and support controls u Help support: tutorials, indexed, context-sensitive

14 Systems Analysis and Design in a Changing World, 3rd Edition 14 Guidelines for Designing Web Sites u Draw from guidelines and rules for designing Windows forms and browser forms u Website uses: l Corporate communication l Customer information and service l Sales, distribution, and marketing u Must work seamlessly with customers 24/7

14 Systems Analysis and Design in a Changing World, 3rd Edition 15 Example: Dialog Design for RMO Phone- Order u Steps in dialog models 1. Record customer information 2. Create new order 3. Record transaction details 4. Produce order confirmation u Traditional approach – produce structure chart u OO approach – expand SSD to include forms

14 Systems Analysis and Design in a Changing World, 3rd Edition 16 Prototype Forms for an Order-Centered Approach to the Dialog

14 Systems Analysis and Design in a Changing World, 3rd Edition 17 Prototype Forms for an Order-Centered Approach to the Dialog ( continued )

14 Systems Analysis and Design in a Changing World, 3rd Edition 18 Summary u User interface is everything user comes into contact with while using the system l Physically, perceptually, and conceptually u To some users, user interface is the system u User-centered design means: l Focusing early on users and their work l Evaluating designs to ensure usability l Applying iterative development

14 Systems Analysis and Design in a Changing World, 3rd Edition 19 Summary ( continued ) u User interface is described with metaphors (desktop, document, dialog) u Interface design guidelines and standards are available from many sources u Dialog design starts with events, adds dialogs for integrity controls, user preferences, help, menus u OO approach provides UML models to document dialog designs, including sequence diagrams, collaboration diagrams, and class diagrams