Android Json Parsing Tutorial:

JSON is a very condense data exchange format. Android includes the json.org libraries which allow to work easily with JSON files.

To do json parsing first of all you have the need to understand the structure of json .Following diagram illustrate the basic tags which we use repeatedly according to the need.

Below is the basic jason format: 

{     "contacts": [         {                 "id": "c200",                 "name": "Lucky Rana",                 "email": "luckyrana@gmail.com",                 "address": "xx-xx-xxxx,x - street, x - country",                 "gender" : "male",                 "phone": {                     "mobile": "+91 0000000000",                     "home": "00 000000",                     "office": "00 000000"                 }         },         {                 "id": "c201",                 "name": "Johnny Depp",                 "email": "deepak chettri@gmail.com",                 "address": "xx-xx-xxxx,x - street, x - country",                 "gender" : "male",                 "phone": {                     "mobile": "+91 0000000000",                     "home": "00 000000",                     "office": "00 000000"                 }         },         .         .         .         .   ] }

Writing JSON Parser Class

In your project create a class file and name it as JSONParser.java. The parser class has a method which will make http request to get JSON data and returns a JSONObject.

JSONParser.java

package com.androidhive.jsonparsing; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.UnsupportedEncodingException; 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 android.util.Log; 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;     } } Json have only three data items which we use to retrieve data: 1. Json array "contacts": [         {                 "id": "c200",                 "name": "Lucky Rana",                 "email": "luckyrana@gmail.com",                 "address": "xx-xx-xxxx,x - street, x - country",                 "gender" : "male",                 "phone": {                     "mobile": "+91 0000000000",                     "home": "00 000000",                     "office": "00 000000"                 }         }] To retrieve this "contact" array we use following syntex: // Creating JSON Parser instance         JSONParser jParser = new JSONParser(); // getting JSON string from URL      JSONObject json = jParser.getJSONFromUrl(url);         try {             // Getting Array of Contacts             contacts = json.getJSONArray("contact");  Log.d("Contact array Data",json.toString());          }  catch (JSONException e)  {              e.printStackTrace();          } 2. Json object "phone": {                     "mobile": "+91 0000000000",                     "home": "00 000000",                     "office": "00 000000"                 } To retrieve this "phone" object data we use following syntex: // Creating JSON Parser instance         JSONParser jParser = new JSONParser(); // getting JSON string from URL   JSONObject json = jParser.getJSONFromUrl(url);         try {             // Getting Array of Contacts             contacts = json.getJSONArray("contact");   // looping through All Contacts             for(int i = 0; i < contacts.length(); i++){                 JSONObject c = contacts.getJSONObject(i);                                   // Phone number is agin JSON Object                 JSONObject phone = c.getJSONObject(phone);   Log.d("Phone object Data",phone.toString());                          }  catch (JSONException e)  {              e.printStackTrace();          } 3. Json string "id": "c200" To retrieve this "phone" object data we use following syntex: // Creating JSON Parser instance         JSONParser jParser = new JSONParser(); // getting JSON string from URL     JSONObject json = jParser.getJSONFromUrl(url);         try {             // Getting Array of Contacts             contacts = json.getJSONArray("contact");  // looping through All Contacts             for(int i = 0; i < contacts.length(); i++){                 JSONObject c = contacts.getJSONObject(i);                                   // Storing each json item in variable                 String id = c.getString("id");                 String name = c.getString("name"); // Phone number is agin JSON Object                 JSONObject phone = c.getJSONObject(phone);                   String mobile = phone.getString("mobile");                 String home = phone.getString("home");                 String office = phone.getString("office");                Log.d("String Data",mobile.toString());          }  catch (JSONException e)  {              e.printStackTrace();          } Example 1:

Here is an example of  twitter json parsing using this url: 

http://search.twitter.com/search.json?q=android