CS 4720 Usability and Accessibility CS 4720 – Web & Mobile Systems

CS 4720 What makes a good interface? Don't say “anything but SIS.” What are it's characteristics? How do you just KNOW that you're using something that has been thought out properly? 2

CS 4720 Not Just the UI The experience begins with the first time you launch an app or go to a web site There are several components here –Initial impression –User interface –80/20 rule (sometimes the 90/10 rule) –Graphic design –Information presentation All of this adds up to the user experience (UX) 3

CS Rules… 10 Rules to Mobile HCI 4

CS 4720 Evaluating an Interface Rule 1: Visibility of system status The system should always keep users informed about what is going on through appropriate feedback within reasonable time. 5

CS 4720 Evaluating an Interface Rule 2: Match the system to the real world The system should follow real-world conventions, making information appear in natural and logical order. 6

CS 4720 Evaluating an Interface Rule 3: The “uh-oh” button Users often choose system functions by mistake (particularly on mobile) and will need a clearly marked “emergency exit” to leave the unwanted state without having to go through extended steps. Systems should support undo and redo. 7

CS 4720 Evaluating an Interface Rule 4: Consistency and standards User should not have to wonder whether different words, situations, or actions mean the same thing. The system should follow platform conventions. 8

CS 4720 Evaluating an Interface Rule 5: Error prevention Add input checks –How many digits in that phone number? –How many digits in that credit card number? –Are there really 39 days in July? 9

CS 4720 Evaluating an Interface Rule 6: Recognition rather than recall An icon should represent the action and should immediately recognizable as to what it does Part of this is following platform standards, part is being consistent in your own application An action/swipe/etc should be consistent across screens 10

CS 4720 Evaluating an Interface Rule 7: Flexibility Accelerators, shortcuts, etc (which are unseen by the novice user) can speed up interactions for the expert user to such an extent that the system can cater to both inexperienced and experienced users. 11

CS 4720 Evaluating an Interface Rule 8: Aesthetic and minimalist design Every extra unit of information in a dialog competes with the relevant units of information and diminishes their relative visibility. 12

CS 4720 Evaluating an Interface Rule 9: Error explanations Error messages should be expressed in plain language (NO CODES), precisely indicate the problem, and constructively suggest a solution. 13

CS 4720 Evaluating an Interface Rule 10: Help! Have reasonable help information available in the app if possible. 14

CS 4720 The Ten Rules 1. Visibility of Status 2. System = Real World 3. The “uh-oh” button 4. Consistency and Standards 5. Error Prevention 6. Recognition rather than Recall 7. Flexibility 8. Minimalist Design 9. Error Explanation 10. Help! 15

CS 4720 Phone-Specific Interface 16 We need to separate two concerns here –The Hardware Interface –The Software Interface What are some specific hardware innovations that we use with cell phones? How do these address the 10 rules?

CS 4720 Hardware Interface Consider the following hardware innovations: –The click wheel –The rocker –The track ball –The home button 17

CS 4720 Software Interface 18 Let's look at a few interfaces

CS 4720 Image Galleries 19

CS 4720 Empty Lists 20

CS 4720 Describing Places 21

CS 4720 Concepts 22 UI's that grow and shrink –Flexible design Softkeys and icon buttons for common tasks Predictive text Others?

CS 4720 One Hand or Two Hands? Large, obvious buttons Controls toward the center of the screen so you don't have to stretch Controls have space between them if possible Put only needed items on the screen Eliminate unnecessary words Make transitions between states obvious Apps: Phone, Contacts, Urbanspoon 23

CS 4720 One Hand or Two Hands? 24 Theoretically, the user is not moving, so controls can be more complex Stylus control Keyboard in landscape mode (soft or hard) More information to proces Apps: Amazon, AllRecipes

CS 4720 Rules of Thumb 25 Easy traversals between states Audio sparingly (remember – audio may be turned off!) Build for the input device (click wheel, touch screen, stylus) Provide shortcuts when possible Try to use direct-manipulation widgets for input with immediate feedback Menus must be tailored to the device input

CS 4720 Rules of Thumb Typing isn't easy – provide ways to remember text Use contextual information whenever possible (use GPS coords automatically in a Google search, have the last contact up for making a phone call, etc) 26

CS 4720 My UI works great now! But it still doesn't look “slick!” Simple is beautiful Get a friend to pick out the color scheme for you. Seriously. Imitation is the greatest form of flattery If all else fails… ask a graphic design student Or check the patterns: – design-patterns-inspiration/ 27