Android : Android getting Longitude and latitude always returns 0.0

I'm trying to get the longitude and latitude for android, here is my code:

    LocationManager locationManager = (LocationManager)
            this_activity.getSystemService(Context.LOCATION_SERVICE);

    LocationListener locationListener = new MyLocationListener();
    locationManager.requestLocationUpdates(
            LocationManager.GPS_PROVIDER, 5000, 10, locationListener);




 public class MyLocationListener implements LocationListener {

    @Override
    public void onLocationChanged(Location loc) {
        longitude = Double.toString(loc.getLongitude());
        latitude = Double.toString(loc.getLatitude());
    }

    @Override
    public void onProviderDisabled(String provider) {}

    @Override
    public void onProviderEnabled(String provider) {}

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {}
}

I'm always getting 0.0s for longitude and latitude