String provider;
if (isNetworkEnabled) {
provider = LocationManager.NETWORK_PROVIDER;
} else {
provider = LocationManager.GPS_PROVIDER;
}
is GPS enabled on the device, with Satellite option set in Security section of mobile settings? because you are assuming that GPS_PROVIDER is enabled, just because NETWORK_PROVIDER is disabled? which is not accurate ...
also manager.getLastKnownLocation(provider);
will return Location
object directly and will not result a call to callback methods in the listenet...
so you need to use either one of them...