I'm writing software which requires cell location updates to be received or checked constantly. The problem I'm having is that when the screen is off: a) notifications stop (using PhonestateListener); b) when a timer is used to check the cell info of the current cell, old cell info is returned.
I've spent a lot of time searching the reason for this and found a couple of posts on this subject. However I never found an answer or a workaround to the problem, accept for having the phone turn the screen on constantly to get a new cell location.
I've check the android RIL source code and it seems as soon as the screen is turned off, a broadcast receiver in the RIL sets the screen state to off and stops URC messages from the modem. I decided to try and call these internal functions to, say, reset the screen state (bad solution!), but I kept getting permission errors due to system intents being created as a result of my actions (I even tried by getting su permission).
Finally, I tried to communicate directly with the modem to send a +CSQ command (using 'invokeOemRilRequestStrings' function in the RIL). However, that part failed as I kept getting errors about object type not being same as expected class type...
So... I would like to know if anyone can point me to a solution to get this thing done. Or is it an impossible thing to do on android without modifying the ROM?
Thanks in advance for your help.
Did you try registering for location updates in a separate Android service having FOREGROUND priority?