We can now access app usage history on an Android device with the new android.app.usage API released as part of Android 5.0 APIs.The system collects the usage data on a per-app basis, aggregating the data over daily, weekly, monthly, and yearly intervals
For each app, the system records the following data:
- The last time the app was used
- The total length of time the app was
in the foreground for that time interval (by day, week, month, or
year) -
Timestamp capturing when a component (identified by a package
and activity name) moved to the foreground or background during a day -
Timestamp capturing when a device configuration changed (such as when
the device orientation changed because of rotation)
Refr : http://developer.android.com/reference/android/app/usage/package-summary.html