@Override
        protected Void doInBackground(Void... arg0) {
            HttpHandler sh = new HttpHandler();
            // Making a request to url and getting response
            String url = "https://sfasys:sfa321@nfdapp.nabatigroup.com/sap/opu/odata/sap/ZPRJ_SD0003_SRV/SFASTOCKSet?$filter=Werks%20eq%20%27P174%27%20and%20Lgort%20eq%20%27GS00%27$";
//            String url = "http://api.androidhive.info/contacts/";
            String jsonStr = sh.makeServiceCall(url);

            Log.e(TAG, "Response from url: " + jsonStr);
            if (jsonStr != null) {
                try {
                    JSONObject jsonObj = new JSONObject(jsonStr);

                    // Getting JSON Array node
                    JSONObject jso = jsonObj.getJSONObject("d");
                    JSONArray contacts = jso.getJSONArray("results");

                    // looping through All Contacts
                    for (int i = 0; i < contacts.length(); i++) {
                        JSONObject c = contacts.getJSONObject(i);
                        String pcode = c.getString("Matnr");
                        String stock = c.getString("Labst");

                        // tmp hash map for single contact
                        HashMap<String, String> contact = new HashMap<>();

                        // adding each child node to HashMap key => value
                        contact.put("pcode", pcode);
                        contact.put("stock", stock);

                        // adding contact to contact list
                        contactList.add(contact);
                    }
                } catch (final JSONException e) {
                    Log.e(TAG, "Json parsing error: " + e.getMessage());
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            Toast.makeText(getApplicationContext(),
                                    "Json parsing error: " + e.getMessage(),
                                    Toast.LENGTH_LONG).show();
                        }
                    });

                }

            } else {
                Log.e(TAG, "Couldn't get json from server.");
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        Toast.makeText(getApplicationContext(),
                                "Couldn't get json from server. Check LogCat for possible errors!",
                                Toast.LENGTH_LONG).show();
                    }
                });
            }

            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            super.onPostExecute(result);
            ListAdapter adapter = new SimpleAdapter(MainActivity.this, contactList,
                    R.layout.list_item, new String[]{ "pcode","stock"},
                    new int[]{R.id.pcode, R.id.stock});
            lv.setAdapter(adapter);
        }