Android Location Wifi doesnt work after rebooting

I am using this code to get the location provider and location.

        mLocationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
        Criteria criteria = new Criteria();
        mBestProvider = mLocationManager.getBestProvider(criteria, false);
        mLocation = mLocati开发者_如何学ConManager.getLastKnownLocation(mBestProvider);

If I turn off the GPS, the location is by network, but if I reboot the phone(so I loss the last position known) and with the 3G data connections off. So I am only using WIFI, I cant get any provider thus therefore any location. However google places app can locate me. I think it might be getting the lastknownlocation.But in that case my others applications should be able to get that location. Any idea whats happening?

The way you are calling this it will return all providers enabled or not because you are passing it false which is probably your intention but have you checked the return string?

mBestProvider = mLocationManager.getBestProvider(criteria, false);

You might be getting the gps provider, or you might be getting the network provider, I have learned not to trust the criteria mechanism because it seems to work differently per carrier and device (I have had some weird bugs reported because of this)

So I always ask specifically for gps and network providers and check last known for both, then use an algo to determine the best one to use.

The network provider can use cell or wifi hotspot/routers to determine location (google keeps a database of wifi information) so it's possible to get a fix with just wifi, not saying that is whats happening but it could be.

If that bears no fruit then it's possible that they are simply caching the last location update in preferences, some applications do that. To test the thesis, failing all of the above just leave the phone in that state and move to a very different location with the same properties if possible, should only take 2000 meters or so. If your app still reports null and places reports the old location you have your answer.

If places did report the newer location with wifi, and your app cannot (assuming you actually verify you are getting the network provider) then there is a chance they are using a private API via the Google Location Server (GLS) / MASF server via partial cell / wifi info but that's at the extreme end of the tin foil curve.