Android JSON Parsing from URL

Question

I'm trying to do a JSON project in Android. This is my code.

For some reason the data isn't displayed in the TextBox as it runs. I'm not sure where I made it wrong.

This is the url from where am trying to grab data: http://cocoalabs.in/demo/ego/index.php/home/read_all_users

Am trying to grab 4 strings and display them to TextViews

This is my code:

MainActivity.Java

public class MainActivity extends Activity
{

static String CocoaInfo="http://cocoalabs.in/demo/ego/index.php/home/read_all_users";
static String clfName = "";
static String cllName = "";
static String clLocation = "";
static String clPh1 = "";


@Override
protected void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    //To perform background tasks, like grabbing info from website and write it to GUI
    new MyAsyncTask().execute();
}

public class MyAsyncTask extends AsyncTask<String, String, String>
{

    @Override
    protected String doInBackground(String... strings)
    {
        /*Get HTTP client that scores streaming uploads & Downloads
        Here download RESTful information from CocoaLabs URL*/
        DefaultHttpClient httpClient = new DefaultHttpClient(new BasicHttpParams());

        /*Use POST method to grab from data from URL*/
        HttpPost httpPost = new HttpPost(CocoaInfo);

        /*Define type of service we're using - JSON service*/
        httpPost.setHeader("Content-type", "application/json");

        /*To Read data from URL*/
        InputStream inputStream = null;

        /*To hold all the data we get from URL*/
        String result = null;

        try
        {
            /*Asking for a response from the web service*/
            HttpResponse response = httpClient.execute(httpPost);

            /*Has the content from URL along with header and other info*/
            HttpEntity entity = response.getEntity();

            /*Get the main content from the URL*/
            inputStream = entity.getContent();

            /*Read data from the stream until buffer is full. Helps to grab in bunch*/
            BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"),8);

            /*Creating StringBuilder to store the read data*/
            StringBuilder theStringBuilder = new StringBuilder();

            /*For storing the read line*/
            String line = null;

            /*Read all the data from buffer until nothing is left*/
            while((line = reader.readLine())!=null)
            {
                /*Append each line to the Builder object*/
                theStringBuilder.append(line + "\n");
            }

            /*After finishing reading all the data*/
            result = theStringBuilder.toString();

        }

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

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

        finally
        {
            try
            {
                /*Close the InputStream*/
                if (inputStream!=null)
                    inputStream.close();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
        }

        /*Create JSON object to hold a bunch of key-value pairs from the JSON source*/
        JSONObject jsonObject;

        /*To print all the information we downloaded in the LogCat for debugging*/
        Log.v("JSONParser RESULT ", result);


        try
        {
            /*Get the JSON object with all the data*/
            jsonObject = new JSONObject(result);

            clfName = jsonObject.getString("fname");
            cllName = jsonObject.getString("lname");
            clLocation = jsonObject.getString("location");
            clPh1 = jsonObject.getString("ph1");

            Log.v("JSONParser RESULT", clfName);
            Log.v("JSONParser RESULT", cllName);
            Log.v("JSONParser RESULT", clLocation);
            Log.v("JSONParser RESULT", clPh1);

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

        return result;

    }

    //This method is called after all background tasks are done
    /*Writes all the information to the TextViews layout*/
    @Override
    protected void onPostExecute(String result)
    {
        /*Find the buttons on the screen*/
        TextView fNameTV = (TextView) findViewById(R.id.fNameTV);
        TextView lNameTV = (TextView) findViewById(R.id.lNameTV);
        TextView locationTV = (TextView) findViewById(R.id.locationTV);
        TextView ph1TV = (TextView) findViewById(R.id.ph1TV);

        /*Change the value to be displayed on TextViews*/
        fNameTV.setText("First Name is" +clfName);
        lNameTV.setText("Last Name is" +cllName);
        locationTV.setText("Location is" +clLocation);
        ph1TV.setText("Phone Number is" +clPh1);

    }
}

}

what is the logcat out put

Vipin Sahu
– Vipin Sahu

2014-12-02 09:20:43 +00:00
Commented Dec 2, 2014 at 9:20 — Vipin Sahu
– Vipin Sahu, Commented Dec 2, 2014 at 9:20

Pedro Oliveira · Accepted Answer · 2014-12-02 09:35:34Z

5

That's because the given json is an array an not an object.

You need to convert if to an array before and iterate it:

JSONArray myArray = new JSONArray(result);

instead of

jsonObject = new JSONObject(result);

To iterate the array a simple for should do it:

  for( i=0;i<myArray.length();i++){
    JSONObject anObjectOfTheArray= myArray.getJSONObject(i);
    Log.v("CONTENT",anObjectOfTheArray.getString("uname"));
   }

edited Dec 2, 2014 at 9:35

answered Dec 2, 2014 at 9:22

Pedro Oliveira

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Comments

Sagar Maiyad · Accepted Answer · 2014-12-02 09:20:47Z

4

Try something like below:

try {
  JSONArray main = new JSONArray(responsestring);

  for( i=0;i<main.length();i++){
    JSONObject mainobj = main.getJSONObject(i);
    String uid = mainobj.getString("uid");
    String uname = mainobj.getString("uname");
   }
  } catch (JSONException e) {
       e.printStackTrace();
 }

answered Dec 2, 2014 at 9:20

Sagar Maiyad

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2 Comments

George Over a year ago

Thank you for the fine answer. This was the simplest workaround. :)

Rafiq Over a year ago

Move the mainobj declaration outside of loop

prakash · Accepted Answer · 2014-12-02 09:30:15Z

    Actually that url contains JSONARRAY and inside jsonobject

    To get the jsonobject in the JSON array

         JSONObject object = jsonarray.getJSONObject(index);


    To get the values from JSON object

    Json values should be Key and value pair format 

        JSONObject myJson = new JSONObject(myJsonString);

        String name = myJson.get("name");

    **Example**

     String s = "{menu:{\"1\":\"sql\", \"2\":\"android\", \"3\":\"mvc\"}}";
        JSONObject jObject  = new JSONObject(s);
        JSONObject  menu = jObject.getJSONObject("menu");

        Map<String,String> map = new HashMap<String,String>();
        Iterator iter = menu.keys();
        while(iter.hasNext()){
            String key = (String)iter.next();
            String value = menu.getString(key);
            map.put(key,value);
        }
**FOR your thing, You have to do like this**

JSONArray arr = new JSONArray(result);
JSONObject jObj = arr.getJSONObject(inedx);
String uid= jObj.getString("uid");

call this in iteration for total number of objects.

Biswajit · Accepted Answer · 2014-12-02 09:50:13Z

0

I think from your end all the codes are correct but there is some problem with the Json you received. Can you please show the logcat message after running your app. I found that it gives Json exception. You need to check the json.

answered Dec 2, 2014 at 9:50

Biswajit

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Comments

Jayasri Kumarasamy · Accepted Answer · 2014-12-02 09:46:12Z

Using this follwing class to get JSONObject :

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

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

import android.util.Log;

public class JSONParser {
    static InputStream is = null;
    static JSONObject jarray = null;
    static String json = "";
    String result = null;

    public JSONParser() {

    }

    public JSONObject getJSONFromUrl(String url) {

        StringBuilder builder = new StringBuilder();
        HttpClient client = new DefaultHttpClient();
        HttpGet httpGet = new HttpGet(url);
        System.out.println(url);
        try {
            System.out.println("httpGet:" + httpGet);
            HttpResponse response = client.execute(httpGet);
            System.out.println("response" + response);
            StatusLine statusLine = response.getStatusLine();
            int statusCode = statusLine.getStatusCode();
            if (statusCode == 200) {
                HttpEntity entity = response.getEntity();
                InputStream content = entity.getContent();
                BufferedReader reader = new BufferedReader(
                        new InputStreamReader(content));
                String line;
                while ((line = reader.readLine()) != null) {
                    builder.append(line);
                    result = builder.toString();
                    System.out.println(builder.toString());

                }
            } else {
                Log.e("==>", "Failed to download file");
            }
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        try {
            jarray = new JSONObject(result);
        } catch (JSONException e1) {
            Log.e("JSON Parser", "Error parsing data " + e1.toString());
        }
        // return JSON String
        return jarray;

    }
}

put the following code in your do in background...

JSONObject c = JSONParser.getJSONFromUrl("put your url here");

try {
clfName= c.getString("fname");
cllName= c.getString("lname");
clLocation= c.getString("location");
clph1 = c.getString("ph1");

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

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