LocationManager lm = (LocationManager)context.getSystemService(Context.LOCATION_SERVICE);
boolean gps_enabled = false;
boolean network_enabled = false;

try {
    gps_enabled = lm.isProviderEnabled(LocationManager.GPS_PROVIDER);
} catch(Exception ex) {}

try {
    network_enabled = lm.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
} catch(Exception ex) {}

if(!gps_enabled && !network_enabled) {
    // notify user
    new AlertDialog.Builder(context)
        .setMessage(R.string.gps_network_not_enabled)
        .setPositiveButton(R.string.open_location_settings, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface paramDialogInterface, int paramInt) {
                context.startActivity(new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS));
            }
        }
        .setNegativeButton(R.string.Cancel,null)
        .show();    
}