MEASUREMENT
In a search or refine form , user can move a slider control to set a minimum / maximum range ( e . g . for prices or budgets )
When users need to set a minimum / maximum price or budget range in order to search for - or refine search results - items , use the horizontal slider control . A slider is easy to swipe horizontally and provides simple visual cues to customise this action . Things to consider : Values can be entered easily . Numbers aren ’ t hidden when slider is being operated ( by fat fingers ). For some range types a discrete slider with a set of stops with predefined values may be better than a continuous range - and , you could add a histogram to a discrete slider to illustrate inventory levels available in each stop .
In a form , user can select times or dates from a picker control ( e . g . for entering travel dates , date of birth or time of arrival )
When users need to select times or dates provide a native time and date picker control , which make selection fast and familiar , and support multiple formats Android can display up to 3 wheels concurrently
iOS up to four wheels concurrently ( each wheel displaying a value in a single category , with formats such as Date and time , Time , Date , and Countdown ).
In travel forms , user can select a date from a visual calendar
Especially when on mobile users are likely not to have a calendar at hand when quickly wanting to perform a task . Make it easy for them to select the correct dates by offering an actual calendar with days of the week from which they can pick .
When app crashes it re-starts and returns the user to the last screen used ( to continue where they left off )
In the event of an app crash , ensure it restarts and returns its state to the last screen used , so that the user can continue where they left off - especially if their journey involved entering data and required effort . Don ’ t require users to re-enter data .
1-second delay in load time can mean a 16 % decrease in customer satisfaction , and 7 % loss in conversions .”
Akamai , 2013
On-screen content and transitions between screens appear fast and responsive ( pauses frustrate and confuse users )
Ensure on-screen content and user actions - and transitions between screens - appear responsive , because unresponsive screens cause users to repeat actions or even close apps . And , if screens are responsive you won ’ t need to use a progress indicator / loading spinner , which focus users on waiting instead of on the task or transition . Onscreen considerations include : Storing screen layout or skeletons locally ( so they display immediately ) Minimising on-screen content ( that needs to load dynamically ) Optimising backend processing ( to load elements in priority order , or predict what a user will need / do next and execute that task ) Using animation to create the effect of screens loading quickly and providing visual feedback of a user action
MEASUREMENT
User timings : if you use Google Analytics , you can measure resource load times of a specific screen ( in Android and iOS apps )
Analytics Mobile Device reports - check conversion rates for different Mobile operating systems and devices
47