Activity Manager Overview

Activity manager is a Symbian platform component used by other components to monitor and react to user activity on the device.

Description

Activity manager is typically in one of the two states, active or inactive, reflecting activity or inactivity on the device. It plays a vital role in implementing functionality such as power management and screen savers. When it passes from one state to the other, it launches a default set of actions to respond to the change. The typical responses are restoring the power when entering a period of activity or bringing up a screen saver when entering a period of inactivity.

The responses to activity and inactivity are implemented as callback functions which are passed to the activity manager by its Start() function. There are two of them, the active callback and the inactive callback.

Inactivity is defined as a lack of activity for a specified period, the inactivity interval. The value of the inactivity interval is also passed to the Activity Manager by its Start() function.

When an activity manager is inactive, it attempts to detect its activity. When a period of inactivity ends with the detection of activity, the activity manager:

calls the active callback
enters the active state
starts monitoring inactivity.

When an activity manager is active, it attempts to detect its inactivity. When a period of activity ends with the detection of inactivity, the response varies. If the inactivity interval has been exceeded, or in other words if inactivity has lasted long enough to require a response, the activity manager:

calls the inactive callback
enters the inactive state
starts monitoring activity

If the inactivity interval has not been exceeded, the Activity Manager reverts to monitoring inactivity.