JSON Value Parsing Android Studio

Question

I am currently learning how to create apps on Android Studio and have been trying to make a JSON connection with a server and bring back the information from the server and display it in my app. I have been able to make the connection as logical shows however I am unclear of the error that faces me and how to solve it. I will show here my two classes I have constructed to make the JSON connection and the error I am shown. When I run the emulator it just says, Unfotunatley, JSONconnection app has stopped working.

Thanks for the help

Error on logcat with exception

04-08 08:10:23.860    1656-1656/com.example.adam.jsonconnection E/JSON Parser﹕ Error parsing data org.json.JSONException: Value [{"id":"170656","RatingValue":"5","DistanceKM":"0.0483604565731744","PostCode":"M1 5QS","Latitude":"53.472442","BusinessName":"Cheeky Coffee Co","Longitude":"-2.240435","RatingDate":"2014-02-06","AddressLine1":"Unit 10, The Quadrangle","AddressLine2":"Chester Street","AddressLine3":"Manchester"},{"id":"171710","RatingValue":"3","DistanceKM":"0.0483604565731744","PostCode":"M1 5QS","Latitude":"53.472442","BusinessName":"Nando's","Longitude":"-2.240435","RatingDate":"2013-01-17","AddressLine1":"Unit 3, The Quadrangle","AddressLine2":"Chester Street","AddressLine3":"Manchester"},{"id":"172780","RatingValue":"4","DistanceKM":"0.0483604565731744","PostCode":"M1 5QS","Latitude":"53.472442","BusinessName":"Zouk Tea Bar & Grill","Longitude":"-2.240435","RatingDate":"2010-06-11","AddressLine1":"Unit 5 The Quadrangle","AddressLine2":"Chester Street","AddressLine3":"Manchester"},{"id":"170593","RatingValue":"5","DistanceKM":"0.0858826413670853","PostCode":"M1 5QA","Latitude":"53.472901","BusinessName":"Caffe Nero","Longitude":"-2.23997","RatingDate":"2011-01-18","AddressLine1":"","AddressLine2":"8A Oxford Road","AddressLine3":"Manchester"},{"id":"171089","RatingValue":"5","DistanceKM":"0.0858826413670853","PostCode":"M1 5QA","Latitude":"53.472901","BusinessName":"Greggs","Longitude":"-2.23997","RatingDate":"2011-01-18","AddressLine1":"","AddressLine2":"10 Oxford Road","AddressLine3":"Manchester"},{"id":"171185","RatingValue":"5","DistanceKM":"0.0858826413670853","PostCode":"M1 5QA","Latitude":"53.472901","BusinessName":"Holiday Inn Express","Longitude":"-2.23997","RatingDate":"2011-03-17","AddressLine1":"","AddressLine2":"2-4 Oxford Road","AddressLine3":"Manchester"},{"id":"171382","RatingValue":"1","DistanceKM":"0.0858826413670853","PostCode":"M1 5QA","Latitude":"53.472901","BusinessName":"Kukoos","Longitude":"-2.23997","RatingDate":"2013-11-18","AddressLine1":"","AddressLine2":"12a Oxford Road","AddressLine3":"Manchester"},{"id":"171404","RatingValue":"-1","DistanceKM":"0.0858826413670853","PostCode":"M1 5QA","Latitude":"53.472901","BusinessName":"Ladbrokes","Longitude":"-2.23997","RatingDate":"2010-11-09","AddressLine1":"","AddressLine2":"10B Oxford Road","AddressLine3":"Manchester"},{"id":"172281","RatingValue":"5","DistanceKM":"0.0858826413670853","PostCode":"M1 5QA","Latitude":"53.472901","BusinessName":"Subway","Longitude":"-2.23997","RatingDate":"2013-10-09","AddressLine1":"","AddressLine2":"12 Oxford Road","AddressLine3":"Manchester"},{"id":"171119","RatingValue":"5","DistanceKM":"0.100210503082758","PostCode":"M1 5GE","Latitude":"53.47208","BusinessName":"H & M Convenience Store","Longitude":"-2.241442","RatingDate":"2010-09-16","AddressLine1":"Student Village","AddressLine2":"Lower Chatham Street","AddressLine3":"Manchester"}] of type org.json.JSONArray cannot be converted to JSONObject
04-08 08:10:23.860    1656-1656/com.example.adam.jsonconnection D/AndroidRuntime﹕ Shutting down VM
04-08 08:10:23.860    1656-1656/com.example.adam.jsonconnection W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xb2cbdb20)
04-08 08:10:23.860    1656-1656/com.example.adam.jsonconnection E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: com.example.adam.jsonconnection, PID: 1656

JSONParser Class

   package com.example.adam.jsonconnection;

import android.util.Log;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;


public class JSONParser {

    static InputStream is = null;
    static JSONObject jObj = null;
    static String json = "";


    // constructor
    public JSONParser() {
    }
    public JSONObject getJSONFromUrl(String url) {

        // Making HTTP request
        try {
            // defaultHttpClient
            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpPost httpPost = new HttpPost(url);
            HttpResponse httpResponse = httpClient.execute(httpPost);
            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    is, "iso-8859-1"), 8);
            StringBuilder sb = new StringBuilder();
            String line = null;
            while ((line = reader.readLine()) != null) {
                sb.append(line + "n");
            }
            is.close();
            json = sb.toString();
        } catch (Exception e) {
            Log.e("Buffer Error", "Error converting result " + e.toString());
        }
        // try parse the string to a JSON object
        try {
            jObj = new JSONObject(json);
        } catch (JSONException e) {
            Log.e("JSON Parser", "Error parsing data " + e.toString());
        }
        // return JSON String
        return jObj;
    }
}

MainActivity Class

    package com.example.adam.jsonconnection;

import android.os.StrictMode;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;

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


public class MainActivity extends ActionBarActivity {



    //URL to get JSON Array
    private static String url = "";

    //JSON Node Names
    private static final String TAG_NEAREST = "nearest";
    private static final String TAG_BusinessName = "BusinessName";

    JSONArray nearest = null;



    @Override
    protected void onCreate(Bundle savedInstanceState) {

        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Creating new JSON Parser
        JSONParser jParser = new JSONParser();

        // Getting JSON from URL
        JSONObject json = jParser.getJSONFromUrl(url);
        try {
            // Getting JSON Array
            nearest = json.getJSONArray(TAG_NEAREST);
            JSONObject c = nearest.getJSONObject(0);

            // Storing  JSON item in a Variable
            String businessName = c.getString(TAG_BusinessName);


            //Importing TextView
            final TextView BusinessNameText = (TextView)findViewById(R.id.BusinessName);

            //Set JSON Data in TextView
            BusinessNameText.setText(businessName);

        } catch (JSONException e) {
            e.printStackTrace();
        }
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

As in log org.json.JSONArray cannot be converted to JSONObject — ρяσѕρєя K
– ρяσѕρєя K, Commented Apr 8, 2015 at 12:42
Is this ThreadPolicy thingy a way you can run server communication in UI thread? I would not recommend that. Have a look at loopj, it makes server communication way, way easier! — Ridcully
– Ridcully, Commented Apr 8, 2015 at 12:56

Ori Lentz · Accepted Answer · 2015-04-08 12:45:35Z

1

You have a JSONArray and you're attempting to create a JSONObject object with it.

Simple change your code to:

try {
    jObj = new JSONArray(json);
} catch (JSONException e) {
    Log.e("JSON Parser", "Error parsing data " + e.toString());
}

Or edit your response so that it is a json object.

answered Apr 8, 2015 at 12:45

Ori Lentz

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2 Comments

midgitads26 Over a year ago

Thank you for the help you have given me here, I now have another error, I have changed the code in the JSONParser class to what you said and the code in the main activity to nearest = json.getJSONArray(Integer.parseInt(TAG_NEAREST)); and the error below now shows..04-08 09:31:35.160 1631-1631/com.example.adam.jsonconnection E/Buffer Error﹕ Error converting result java.lang.NullPointerException: lock == null 04-08 09:31:35.160 1631-1631/com.example.adam.jsonconnection E/JSON Parser﹕ Error parsing data org.json.JSONException: End of input at character 0 of –

Ori Lentz Over a year ago

It seems like you're trying to parse the string TAG_NEAREST (which is simply "nearest")?

Kaushik · Accepted Answer · 2015-04-08 12:51:30Z

0

Your JSON is an Array from root, so you must change from:

JSONObject json = jParser.getJSONFromUrl(url);

to

JSONArray json = jParser.getJSONFromUrl(url);

and return a JSONArray from getJSONFromUrl

// try parse the string to a JSON object
try {
   jObj = new JSONArray(json);
} catch (JSONException e) {
   Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;

edited Apr 8, 2015 at 12:51

Kaushik

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answered Apr 8, 2015 at 12:46

Marcos Vasconcelos

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1 Comment

midgitads26 Over a year ago

Thank you for the help you have given me here, I now have another error, I have changed the code in the JSONParser class to what you said and the code in the main activity to nearest = json.getJSONArray(Integer.parseInt(TAG_NEAREST)); and the error below now shows..04-08 09:31:35.160 1631-1631/com.example.adam.jsonconnection E/Buffer Error﹕ Error converting result java.lang.NullPointerException: lock == null 04-08 09:31:35.160 1631-1631/com.example.adam.jsonconnection E/JSON Parser﹕ Error parsing data org.json.JSONException: End of input at character 0 of

NoVa.code · Accepted Answer · 2015-04-08 14:26:37Z

0

I suggest you to use:

jsonObject.optString("your_key");

instead of:

jsonObject.getString("your_key");

this will automatically handle possible "null" values

answered Apr 8, 2015 at 14:26

NoVa.code

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