Actions and feedback

In a mobile environment, the user's attention is often easily diverted. For this reason, users do not tolerate long delays without any feedback. This means that mobile applications need to respond faster to user actions than what would be acceptable in desktop computers.

For some actions, such as opening an application, users want an immediate response. For other actions, such as deleting a large number of files, users can accept a certain amount of delay. The minimum requirement is that the feedback is given instantly, even if the operations take a longer time.

Figure: Informative feedback keeps the user on track.

If there are actions that do not have a visible outcome for the user in the current context, the user should get confirmation feedback without having to change views. For example, if the user changes the visual appearance of the home screen in device settings, they should not have to go to the home screen to confirm if something was changed.

Give users feedback on their actions; feedback should begin within 100 ms of the action.
If the action takes from 0.5 to 2 seconds, provide an indication that something is happening.
If the expected pause is longer than 2 seconds, users need to know how much longer they must wait. A progress bar or an animation should be displayed and users should be able to cancel the current action. It is often better to display even vague estimations rather than no information at all.
Application reaction times should not vary much. If users cannot anticipate whether the action takes 0.1 or 5 seconds, they may get annoyed.

Feedback pop-ups should be used with consideration, as too frequent feedback can annoy the users.

Vibration and audio feedback is also possible. However, many users tend to completely switch off especially audio feedback and alert tones in device settings.