# Modules.CoreMotion.MotionActivity

This method runs asynchronously, returning immediately and delivering the results to the specified callback. The system stores only the last seven days worth of activity data at most. If there are no samples for the specified range of time, an error object with the code ERROR_UNKNOWN is passed to the callback.

This method initiates the tracking of motion data asynchronously. Upon calling this method, the motion activity manager executes the callback, reporting the current motion in effect for the device. After that, the motion activity manager executes the callback only when the motion data changes.

The callback is executed on a best effort basis and updates are not delivered while your app is suspended. If updates arrived while your app was suspended, the last update is delivered to your app when it resumes execution. To get all of the updates that occurred while your app was suspended, use the queryActivity method.

Upon starting activity updates, the motion activity manager reports changes to its callback until you call the stopActivityUpdates method. If you call this method again with a new callback, the activity manager stops delivering updates to the old callback and delivers them to the new callback instead.