Menu/submenu using get

Question

I have a submenu menu very similar to the image. I also have a database storing categories/subcategories.

I’d like to make a Get at the bank, so it would appear on my menu.

Code I’m using :

private class ArrayList extends AsyncTask<Void, String, String> {

  private final String mCat;
  ArrayList(String cat) {
      mCat = cat;
  }

  @Override
  protected String doInBackground(Void... String) {

      HttpURLConnection httpCon = null;
      StringBuilder result = new StringBuilder();
      //  Toast.makeText(LoginActivity.this,"No começo de doInbackground....",Toast.LENGTH_LONG).show();
      //   int id = 1;

      try {
          String urlLogin = "http://192.168.1.207/api/v2/bookdemo/_table/cad_categorias?fields=tx_cat";

          URL url = new URL(urlLogin);
          httpCon = (HttpURLConnection) url.openConnection();

          httpCon.setRequestProperty("Accept", "application/json");
          httpCon.setRequestMethod("GET");
          httpCon.setRequestProperty("X-DreamFactory-Api-Key", "XXXXXXXX");
          httpCon.setRequestProperty("X-DreamFactory-Session-Token", "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJzdWIiOjE0LCJ1c2VyX2lkIjoxNCwiZW1haWwiOiJ0aGlhZ28uY2FtYXJnb0Bldm9sdXRpb25pdC5jb20uYnIiLCJmb3JldmVyIjpmYWxzZSwiaXNzIjoiaHR0cDpcL1wvMTkyLjE2OC4xLjIwN1wvYXBpXC92Mlwvc3lzdGVtXC9hZG1pblwvc2Vzc2lvbiIsImlhdCI6MTQ5NTU2MDI1MCwiZXhwIjoxNDk1NTYzODUwLCJuYmYiOjE0OTU1NjAyNTAsImp0aSXXXXXXXXX.oQP7XjL1KbM7vhYu8Jcn_GHcJtzD9lqFOlD4F7u7wrI");
          httpCon.setRequestProperty("Authorization", "Basic  XXXXXXXX");

          InputStream in = new BufferedInputStream(httpCon.getInputStream());
          BufferedReader reader = new BufferedReader(new InputStreamReader(in));
          String line;
          while ((line = reader.readLine()) != null) {
              result.append(line);
          }

      } catch (Exception e) {
          e.printStackTrace();
      } finally {
          httpCon.disconnect();
      }
      System.out.println(result.toString());

      return result.toString();
  }

    @Override
    protected void onPostExecute(final String result) {
        super.onPostExecute(result);
        try {
          JSONObject json = new JSONObject(result);
          System.out.println(json.getString("resource"));
          JSONArray array = new JSONArray(json.getString("resource"));
          for (int i = 0; i < array.length(); i++) {
              JSONObject jsonObj = array.getJSONObject(i);
              String cat = jsonObj.getString("tx_email");
          }
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }

    private void initDrawer() {
        drawer = (DrawerLayout) findViewById(R.id.drawer_layout);

        drawerList = (ExpandableListView) findViewById(R.id.left_drawer);
        // preparing list data
        prepareListData();
        drawerList.setAdapter(new NavAdapter(this, listDataHeader, listDataChild));
        drawerList.setOnChildClickListener(this);
        actionBarDrawerToggle = 
          new ActionBarDrawerToggle(
              this, drawer, toolbar, R.string.drawer_open, 
              R.string.drawer_close
          ) {
              @Override
              public void onDrawerClosed(View drawerView) {
                  // Code here will be triggered once the drawer closes as we 
                  //don't want anything to happen so we leave this blank
                  super.onDrawerClosed(drawerView);
              }

              @Override
              public void onDrawerOpened(View drawerView) {
                  // Code here will be triggered once the drawer open as we 
                  //don't want anything to happen so we leave this blank
                  super.onDrawerOpened(drawerView);
              }
            };

        //Setting the actionbarToggle to drawer layout
        drawer.setDrawerListener(actionBarDrawerToggle);

        //calling sync state is necessay or else your hamburger icon wont show up
        actionBarDrawerToggle.syncState();
    }

    /*
     * Preparing the list data
     */
    private void prepareListData() {

      listDataChild = new HashMap<String, List<String>>();

      // Adding headers
      Resources res = getResources();
      String[] headers = res.getStringArray(R.array.nav_drawer_labels);
      listDataHeader = Arrays.asList(headers);

      Button btnaddlivro = (Button) findViewById(R.id.btnaddlivro);
      btnaddlivro.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View view) {
              Intent intent = new Intent(MainActivity2.this, Activity_addinf.class);
              startActivity(intent);
          }

      });

      // Static method
      List<String> home, friends, notifs;
      String[] shome, sfriends, snotifs;

      friends = Arrays.asList(cat);

      sfriends = res.getStringArray(R.array.elements_Portugues);
      friends = Arrays.asList(sfriends);

      snotifs = res.getStringArray(R.array.elements_Matemática);
      notifs = Arrays.asList(snotifs);
      // Add to hashMap
      listDataChild.put(listDataHeader.get(0), cat); // Header, Child data
      listDataChild.put(listDataHeader.get(1), friends);
      listDataChild.put(listDataHeader.get(2), notifs);
    }

    @Override
    public boolean onChildClick(ExpandableListView parent, View v,
            int groupPosition, int childPosition, long id) {
        Toast.makeText(
          getApplicationContext(),
          listDataHeader.get(groupPosition)
                  + " : "
                  + listDataChild.get(
                  listDataHeader.get(groupPosition)).get(
                  childPosition), Toast.LENGTH_SHORT
        ).show();
      return false;
    }
}