Designing a mobile app Chris Greenhalgh G54UBI / 2011-03-02 1Chris Greenhalgh ([email protected])

Chris Greenhalgh ([email protected]) 1

Designing a mobile app

Chris GreenhalghG54UBI / 2011-03-02


First…

• Work out what the application is meant to do, e.g.– Identify possible users and situations of use– Identify use cases, i.e. main activities– Write one or more user stories


Example: tree walk

• Existing paper walking guide to trees and gardens on the University Park campus

• (as used for GLF)


Example: user story

• Ali is visiting University Park and installs the tree walk app on her Android phone

• She starts the app and the main view shows the walking map

• As she explores the area the app chimes and pops up more detail of nearby points of interest

• She reads these with interest before continuing her walk


D1. Identify application “screens”

• Work out how the application will be divided into screens, e.g.– Splash screen– Map overview– Location detail view– Help– …


D1: Example

• Welcome screen• Main map screen• Point of interest screens– 4: Acer saccharinum;

5: Ulmus ‘Sapporo Autumn Gold’; 7: Metasequoia glyptostroboides

• Where am I? screen (native app)• Help screen


Non-GUI apps

• “Screens” are most relevant for GUI-based apps, but still a necessary starting point for other apps, e.g. audio• For non-GUI apps there may be other application “modes”

which effectively sub-divide/specialise each screen– E.g. “seeking”, “detail”, …

• These should be identified and charted in the same way as screens


D2. Define screen “flow”

• Work out how the application moves from one screen to another, e.g.– On direct user input (e.g. a button)– On “back”– On timer– On sensor input condition


D2: Example

Welcome

Main(map)

Where?

Detail (1)Detail (1)

Detail (1)

Help

BackBack

Back

“Start”button

“Help”button“Where?”

button

GPS trigger


D3. “wireframe” each screen

• For each screen, work out what GUI elements will make it up and roughly how they will be laid out, e.g.– Images, Text, Buttons, Gauges, …

• Specify what each GUI element will do• Highlight any elements that change– These may be domain model objects or

properties! (see 6)


D3: Example

Welcome Main

Welcome to the University Park

tree walk

StartHelp Where

am I?

GPS:


D3: Example

Help Map (native app)

OK

Blah blah blah blah Blah blah blah blahBlah blah blah blahBlah blah blah blahBlah blah blah blahBlah blah blah blah

Tree Walk Help


D3: Example

Detail 4 …

OK

On the right hand side of the drive is a groupof young Acer saccharinum, the Silver maple, introduced from Eastern North America in 1725. It is a fast growing tree.

4: Silver Maple


D4. Specify sensor input and effects

• Identify – Which sensors are monitored– When, e.g. on which screens– How sensor input is processed• E.g. identify region entry

– Which screen elements are affected and how• E.g. signal strength, user position

– What other actions result• E.g. screen transitions


D4: Example

• Sensor is GPS• Only required on main screen• Accuracy is shown on main screen GPS gauge• Position is checked against interest regions• Entering interest region switches to detail

screen


D5. Specify any “invisible” activities

• E.g. – Network operations– Audio / sound effects– Background processing


D5: Example

• Transition to detail view accompanied by “chime” sound-effect


Optional: D6. Define/Refine the domain model

• Identify the classes of “things” that your application “knows” about, e.g.– Trees, shops, exhibits, places, …

• Identify what your application “knows” about each “thing”, i.e.– the properties and relationships that are shown to

the user (see 3)– The properties and relationships that are used

internally when deciding what to do (see 2, 4, 5)This activity can be done and re-done at any stage through the designand refinement process


Why D6?

• Aim to separate – Code = behaviour– Screen and element “templates” = appearance– Domain data = data values = specific content

• Because– Code is harder to change– Specific content can be represented more concisely as

data values– Specific content can be changed more easily

• Potentially dynamically, e.g. from a server


D6: Example

• “Things” are “points of interest”– Or perhaps more specifically “trees”

• A point of interest has:– A spatial trigger region– A map key (e.g. “4”) – “Detail” information• A title• Some descriptive text


Iterate…

• Review and refine taking account of– Walkthroughs– Details emerging from later stages– Other use cases– Paper prototyping– Implementation constraints– User tests


Summary

• D1. Identify application “screens”• D2. Define screen “flow”• D3. “wireframe” each screen• D4. Specify sensor input and effects• D5. Specify any “invisible” activities• D6. Define/Refine the domain model

(optional)

Designing a mobile app Chris Greenhalgh G54UBI / 2011-03-02 1Chris Greenhalgh ([email protected])

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