Variable null outside of asynctask in android

[Junk_1]

I have a problem with asynctask in android Java.
it's the same problem as this : http://stackoverflow.com/questions/15457482/variable-returns-null-outside-asynctask-android
my asynctask get data from a url , to get direction of google maps !
This is where I call my code , inside onrespondre => myvaraible have data but outside the variable is null.

    public void onResponse(String status, Document doc, final GoogleDirection gd) {
    mMap.addMarker(new MarkerOptions()
            .position(
                    new LatLng(myLocation.getLatitude(), myLocation
                            .getLongitude()))
            .icon(BitmapDescriptorFactory
                    .defaultMarker(BitmapDescriptorFactory.HUE_BLUE)));
    mMap.addMarker(new MarkerOptions().position(Position).icon(
            BitmapDescriptorFactory
                    .defaultMarker(BitmapDescriptorFactory.HUE_RED)));

    mMap.addPolyline(gd.getPolyline(doc, 3, Color.RED));
    MyVariable = gd.getTotalDurationValue(doc);
}

this is the class :

    private class RequestTask extends AsyncTask<String, Void, Document> {
    protected Document doInBackground(String... url) {
        try {
            HttpClient httpClient = new DefaultHttpClient();
            HttpContext localContext = new BasicHttpContext();
            HttpPost httpPost = new HttpPost(url[0]);
            HttpResponse response = httpClient.execute(httpPost,
                    localContext);
            InputStream in = response.getEntity().getContent();
            DocumentBuilder builder = DocumentBuilderFactory.newInstance()
                    .newDocumentBuilder();

            return builder.parse(in);
        } catch (IOException e) {
            e.printStackTrace();
        } catch (ParserConfigurationException e) {
            e.printStackTrace();
        } catch (SAXException e) {
            e.printStackTrace();
        }

        return null;
    }

    protected void onPostExecute(Document doc) {
        super.onPostExecute(doc);

        if (mDirectionListener != null) {
            mDirectionListener.onResponse(getStatus(doc), doc,
                    GoogleDirection.this);
        }
    }

    private String getStatus(Document doc) {
        NodeList nl1 = doc.getElementsByTagName("status");
        Node node1 = nl1.item(0);

        if (isLogging) {
            Log.i("GoogleDirection", "Status : " + node1.getTextContent());
        }

        return node1.getTextContent();
    }
}