Can the android geofencing system (Google Play Services) trigger events when the phone is sleeping

Question

I'm trying to find out if the Google Play Services geofencing and location system can be practically used for background location monitoring.

An example scenario is that I have the phone in my pocket, and enter a geofenced area - will the event handler in my app be triggered so I can deal with the event as appropriate, or is the system only intended to be used whilst the phone is awake and the app in the foreground?

I've been banging away at the example code, and so far haven't managed to make it work in this way - or find docs fully addressing this - it seems to be too new for people to be using it much.

Obviously the phone doesn't use GPS continually whilst sleeping, or the battery would run down quickly, but I'm wondering if the broad network location is monitored and used for this purpose (or to discover if the device is within short distance of a geofence, to know that it's worth polling the GPS periodically to find if it has been crossed.)

Answer 1

This answer (by Commonsware) to another question seems to answer the general thrust of the question, though more testing is required to answer some of the more detailed aspects about background location availability, accuracy and geofence reliability.

Commonsware

Answer 2

Geofence if implemented properly will work even when your app is in background and it can be handled from ReceiveTransitionsIntentService In the Service you can create notification and alert the Users to bring back to your APP.

But As per the Documentation, If the Location Services is Disabled by the User on the Device your Registered Geofences will be removed and you have to Re-add all the Geofences. (NOT SURE HOW CAN WE ADD THE GEOFENCES BACK in BACKGROUND DID NOT FIGURE OUT THE SOLUTION YET FOR THIS)

Also in other cases like when the Device is Switched Off / Battery is Drained / Restarted Most probably the Geofences are Removed and we have to reset the Geofences back (However i cannot confirm this as have not found this anywhere in documentation but while testing i have figured out this issue)