Getting StackOverFlowError in Android over a Recursive Call while trying to parse JSON Data

Question

I am trying to learn how to parse JSON data in Android. I referred to a tutorial here: http://www.androidhive.info/2012/01/android-json-parsing-tutorial/

All I got was a StackOverFlowError whose resolution I am unable to figure out. Any help with this will be appreciated. You can find all the relevant Java code below. Please feel free to tell me if you need the code for XML files as well.

Code for ServiceHandler class:

    import org.apache.http.HttpEntity;
    import org.apache.http.HttpResponse;
    import org.apache.http.NameValuePair;
    import org.apache.http.client.ClientProtocolException;
    import org.apache.http.client.entity.UrlEncodedFormEntity;
    import org.apache.http.client.methods.HttpGet;
    import org.apache.http.client.methods.HttpPost;
    import org.apache.http.client.utils.URLEncodedUtils;
    import org.apache.http.impl.client.DefaultHttpClient;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.List;

/**
 * Created by  on 02-07-2015.
 */
public class ServiceHandler {
    static String response = null;
    public final static int GET = 1;
    public final static int POST = 2;

    public ServiceHandler() {
    }

    public String makeServiceCall(String url, int method) {
        return this.makeServiceCall(url, method);
    }

    public String makeServiceCall(String url, int method, List<NameValuePair> params) {

        try {
            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpEntity httpEntity = null;
            HttpResponse httpResponse = null;

            if (method == POST) {
                HttpPost httpPost = new HttpPost(url);
                if (params != null) {
                    httpPost.setEntity(new UrlEncodedFormEntity(params));
                }

                httpResponse = httpClient.execute(httpPost);

            } else if (method == GET) {
                if (params != null) {
                    String paramString = URLEncodedUtils.format(params, "utf-8");
                    url += "?" + paramString;
                }

                HttpGet httpGet = new HttpGet(url);
                httpResponse = httpClient.execute(httpGet);

            }
        } catch (UnsupportedEncodingException ue) {
            ue.printStackTrace();
        } catch (ClientProtocolException ce) {
            ce.printStackTrace();
        } catch (IOException io) {
            io.printStackTrace();
        }

        return response;
    }
}

Code for JSONActivity Activity:

import android.app.ListActivity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.ArrayList;
import java.util.HashMap;

/**
 * Created by  on 03-07-2015.
 */
public class JSONActivity extends ListActivity {

    private ProgressDialog pDialog;
    private static String url = "http://api.androidhive.info/contacts/";
    private static final String TAG_CONTACTS = "contacts";
    private static final String TAG_ID = "id";
    private static final String TAG_NAME = "name";
    private static final String TAG_EMAIL = "email";
    private static final String TAG_ADDRESS = "address";
    private static final String TAG_GENDER = "gender";
    private static final String TAG_PHONE = "phone";
    private static final String TAG_PHONE_MOBILE = "mobile";
    private static final String TAG_PHONE_HOME = "home";
    private static final String TAG_PHONE_OFFICE = "office";

    JSONArray contacts=null;
    ArrayList<HashMap<String, String>> contactList;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.webservicestrial);
        contactList = new ArrayList<HashMap<String, String>>();
        ListView lv = getListView();
        new GetContacts().execute();
    }

    private class GetContacts extends AsyncTask<Void, Void, Void>{
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(JSONActivity.this);
            pDialog.setMessage("Fetching...");
            pDialog.setCancelable(false);
            pDialog.show();
        }

        @Override
        protected void onPostExecute(Void aVoid) {
            super.onPostExecute(aVoid);
            if (pDialog.isShowing())
                pDialog.dismiss();
            ListAdapter adapter = new SimpleAdapter(
                    JSONActivity.this, contactList,
                    R.layout.list_item, new String[] { TAG_NAME, TAG_EMAIL,
                    TAG_PHONE_MOBILE }, new int[] { R.id.name,
                    R.id.email, R.id.mobile });

            setListAdapter(adapter);

        }

        @Override
        protected Void doInBackground(Void... params) {
            ServiceHandler sh = new ServiceHandler();
            String jsonStr = sh.makeServiceCall(url,ServiceHandler.GET);
            Log.d("Response:", ">"+jsonStr);
            if (jsonStr!=null) {
                try {
                    JSONObject jsonObject = new JSONObject(jsonStr);
                    contacts = jsonObject.getJSONArray(TAG_CONTACTS);
                    for (int i = 0; i < contacts.length(); i++) {
                        JSONObject c = contacts.getJSONObject(i);

                        String id = c.getString(TAG_ID);
                        String name = c.getString(TAG_NAME);
                        String email = c.getString(TAG_EMAIL);
                        String address = c.getString(TAG_ADDRESS);
                        String gender = c.getString(TAG_GENDER);

                        // Phone node is JSON Object
                        JSONObject phone = c.getJSONObject(TAG_PHONE);
                        String mobile = phone.getString(TAG_PHONE_MOBILE);
                        String home = phone.getString(TAG_PHONE_HOME);
                        String office = phone.getString(TAG_PHONE_OFFICE);

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

                        // adding each child node to HashMap key => value
                        contact.put(TAG_ID, id);
                        contact.put(TAG_NAME, name);
                        contact.put(TAG_EMAIL, email);
                        contact.put(TAG_PHONE_MOBILE, mobile);

                        // adding contact to contact list
                        contactList.add(contact);
                    }

                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }else {Log.e("ServiceHandler", "Couldn't get any data from the url");}

            return null;
        }
    }
}

Answer 1

public String makeServiceCall(String url, int method) {
    return this.makeServiceCall(url, method);
}

This method is calling itself, hence resulting in a Stack overflow. You probably meant to access the other makeServiceCall method. Therefore you have to add the List<NameValuePair> param

Answer 2

public String makeServiceCall(String url, int method) {
  return this.makeServiceCall(url, method);
}

This is an infinite loop. You have to add the third parameter ( List<NameValuePair> ) when calling the method, for example:

public String makeServiceCall(String url, int method) {
  return this.makeServiceCall(url, method, new ArrayList<NameValuePair>());
}