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How to parse JSON with AsyncTask?

I tried to parse some strings from this JSON-site:
I wrote this code with asynctask:
package com.example.nortti.jsonexample;
import android.app.Activity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
public class MainActivity extends Activity {
TextView txView;
//URL to get JSON Array
private static String url = "http://localhost:10101/api/stats/1";
//JSON Node Names
private static final String TAG_USER = "";
private static final String TAG_NAME = "PersonName";
private static final String TAG_EMAIL = "Rank";
JSONArray user;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
user = null;
new JSONParse().execute();
}
private class JSONParse extends AsyncTask<String, String, JSONObject> {
private ProgressDialog pDialog;
#Override
protected void onPreExecute() {
super.onPreExecute();
txView = (TextView)findViewById(R.id.txView);
pDialog = new ProgressDialog(MainActivity.this);
pDialog.setMessage("Getting Data ...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
#Override
protected JSONObject doInBackground(String... args) {
JSONParser jParser = new JSONParser();
// Getting JSON from URL
JSONObject json = jParser.getJSONFromUrl(url);
return json;
}
#Override
protected void onPostExecute(JSONObject json) {
pDialog.dismiss();
try {
// Getting JSON Array
user = json.getJSONArray("ArrayOfCommonStatViewModel");
Toast.makeText(getApplication(),user.toString(),Toast.LENGTH_SHORT).show();
JSONObject c = user.getJSONObject(0);
// Storing JSON item in a Variable
String name = c.getString(TAG_NAME);
String email = c.getString(TAG_EMAIL);
//Set JSON Data in TextView
txView.setText(name+" " +email);
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}
And I have another class like:
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.HttpGet;
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();
HttpGet httpPost = new HttpGet(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;
}
}
But it says that I have a NullPointerException
I want to get a JSONArray to get information and put it into a ListView.
UPD: Here is JSON screenshot
UPD2: full log
12-17 14:17:03.712 20308-20308/com.example.nortti.politrange E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.nortti.politrange, PID: 20308
android.os.NetworkOnMainThreadException
at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1147)
at java.net.InetAddress.lookupHostByName(InetAddress.java:418)
at java.net.InetAddress.getAllByNameImpl(InetAddress.java:252)
at java.net.InetAddress.getAllByName(InetAddress.java:215)
at org.apache.http.impl.conn.SystemDefaultDnsResolver.resolve(SystemDefaultDnsResolver.java:44)
at org.apache.http.impl.conn.HttpClientConnectionOperator.connect(HttpClientConnectionOperator.java:102)
at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.connect(PoolingHttpClientConnectionManager.java:318)
at org.apache.http.impl.execchain.MainClientExec.establishRoute(MainClientExec.java:373)
at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:225)
at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:195)
at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:86)
at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:108)
at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:178)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:82)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:106)
at com.example.nortti.politrange.utils.WebApiAdapter.select(WebApiAdapter.java:33)
at com.example.nortti.politrange.intefaces.impls.PersonCatalog.populateData(PersonCatalog.java:37)
at com.example.nortti.politrange.views.GeneralFragment.listData(GeneralFragment.java:65)
at com.example.nortti.politrange.views.GeneralFragment.onClick(GeneralFragment.java:88)
at android.view.View.performClick(View.java:4756)
at android.view.View$PerformClick.run(View.java:19761)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5253)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:900)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:695)

you are getting a NetworkOnMainThread exception because you are implementing a network operation in a UI thread so for loading the json data from your localhost you need to implement a seperate thread for it

You are getting NetworkOrMainThreadException.
Put below code on onCreate():
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
Hope this will help you.

You are trying to parse an XML document with a JSON Parser, it won't work. Let's take a look on this link , it will show you how to parse an XML document (in Android environment) on a proper way:

The content that you are trying to parse is actually xml not JSON. If you need to do network requests, parse the JSON, you can use Retrofit library. It is very simple and hassle-free. Here is a nice tutorial for the same. Hope it helps.

instead of developping the whole parsing code, try to use the Volley library of Google, it's an asynchrone library for parsing JSON.
here is a good tutorial.

enter code here
////In android studio add http client and http core libs/////
class mytask extends AsyncTask {
#Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
}
#Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
String url = "http://192.168.1.13/mywebservice/getbook.php";
json = getJSONFromUrl(url);
return null;
}
#Override
protected void onPostExecute(Void result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
Toast.makeText(ctx, json, Toast.LENGTH_LONG).show();
parser_01();
}
}
// from url to json object starts.......................................
public String 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");
sb.append(line);
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
return json;
}
// from url to json object Ends.......................................
public void parser_01() {
try {
String jstring = json;
JSONObject jobject = new JSONObject(jstring);
JSONArray bookarray = jobject.getJSONArray("data");
for (int i = 0; i < bookarray.length(); i++) {
String isdn = bookarray.getJSONObject(i).getString("isdn") + "";
String title = bookarray.getJSONObject(i).getString("title") + "";
String author = bookarray.getJSONObject(i).getString("author") + "";
String price = bookarray.getJSONObject(i).getString("price") + "";
}
} catch (Exception e) {
// TODO: handle exception
}
}

Value [] at 0 of type org.json.JSONArray cannot be converted to JSONObject in android?

I am trying to access a json array from android. But it shows an exception. This is my android code used for retrieving the json array:
protected void showList(){
final String TAG_RESULTS="result";
final String TAG_USERNAME="username";
final String TAG_NAME = "message_recd";
final String TAG_ADD ="message_sent";
ArrayList<HashMap<String, String>> personList;
personList = new ArrayList<HashMap<String,String>>();
//for tesitng
JSONObject jObject=null;
//
try {
//for testing
//
JSONObject json = new JSONObject(myJSON);
JSONArray peoples =json.getJSONArray("emparray");
for(int i=0;i<peoples.length();i++){
JSONObject c = peoples.getJSONObject(i);
String name=null, address=null;
name = c.getString("user_id");
address = c.getString("crtloc_lat");
HashMap<String,String> persons = new HashMap<String,String>();
persons.put("user_id",name);
persons.put("crtloc_lat",address);
personList.add(persons);
Toast.makeText(MapsActivity.this, "woow id"+name, Toast.LENGTH_SHORT).show();
}
} catch (JSONException e) {
Log.e("errore",e.toString());
e.printStackTrace();
}
}
public void getData(){
class GetDataJSON extends AsyncTask<String, Void, String>{
#Override
protected String doInBackground(String... params) {
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
// nameValuePairs.add(new BasicNameValuePair("username", fName));
DefaultHttpClient httpclient = new DefaultHttpClient(new BasicHttpParams());
HttpPost httppost = new HttpPost("http://abh.netai.net/abhfiles/searchProfession.php");
// Depends on your web service
httppost.setHeader("Content-type", "application/json");
InputStream inputStream = null;
String result = null;
try {
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
inputStream = entity.getContent();
// json is UTF-8 by default
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null)
{
sb.append(line + "\n");
}
result = sb.toString();
} catch (Exception e) {
// Oops
}
finally {
try{if(inputStream != null)inputStream.close();}catch(Exception squish){}
}
return result;
}
#Override
protected void onPostExecute(String result){
myJSON=result;
showList();
}
}
GetDataJSON g = new GetDataJSON();
g.execute();
}
php file
<?php
require "config.php";
$con = mysqli_connect(HOST,USER,PASS,DB);
$pro_id=0;
$sql="SELECT user.user_id, current_location.crtloc_lat,current_location.crtloc_lng FROM user INNER JOIN current_location
where user.user_id=current_location.user_id AND user.pro_id='$pro_id'";
$result = mysqli_query($con, $sql) or die("Error in Selecting " . mysqli_error($con));
//create an array
$emparray[] = array();
while($row =mysqli_fetch_assoc($result))
{
$emparray[] = $row;
}
echo json_encode($emparray);
//close the db connection
mysqli_close($con);
?>
and the json array
[[],{"user_id":"77","crtloc_lat":"34.769638","crtloc_lng":"72.361145"},{"user_id":"76","crtloc_lat":"34.769566","crtloc_lng":"72.361031"},{"user_id":"87","crtloc_lat":"33.697117","crtloc_lng":"72.976631"},{"user_id":"86","crtloc_lat":"33.697117","crtloc_lng":"72.976631"}]
the error it show me is this
Value [[],{"user_id":"77","crtloc_lat":"34.769638","crtloc_lng":"72.361145"},{"user_id":"76","crtloc_lat":"34.769749","crtloc_lng":"72.361168"},{"user_id":"87","crtloc_lat":"33.697117","crtloc_lng":"72.976631"}] of type org.json.JSONArray cannot be converted to JSONObject

It is giving you this error because the first object in the array is not a JSONObject but an JSONArray following 4 JSONObjects.
[
[],
{
"user_id": "77",
"crtloc_lat": "34.769638",
"crtloc_lng": "72.361145"
},]
As you can see you expect it to always be a JSONObject.
JSONObject c = peoples.getJSONObject(i);
Anticipate on that first JSONArray in the list.

parsing json data in API url using jsonparser

I have a JSON data in this URL : http://api.pemiluapi.org/calonpresiden/api/caleg/jk?apiKey=56513c05217f73e6be82d5542368ae4f
when I try parsing using this jsonparser code :
package percobaan;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.List;
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 org.json.JSONException;
import org.json.JSONObject;
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
public String makeHttpRequest(String url, String method) {
return this.makeHttpRequest(url, method, null);
}
public JSONObject getJSONFromUrl(String url, List<NameValuePair> params) {
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
httpPost.setEntity(new UrlEncodedFormEntity(params));
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 sBuilder = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sBuilder.append(line + "\n");
}
is.close();
json = sBuilder.toString();
} catch (Exception exception) {
exception.printStackTrace();
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
}
// return JSON String
return jObj;
}
// function get json from url
// by making HTTP POST or GET mehtod
public String makeHttpRequest(String url, String method,
List<NameValuePair> params) {
// Making HTTP request
try {
DefaultHttpClient httpClient = new DefaultHttpClient();
// check for request method
if (method == "POST") {
HttpPost httpPost = new HttpPost(url);
if (params != null) {
httpPost.setEntity(new UrlEncodedFormEntity(params));
}
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} else if (method == "GET") {
if (params != null) {
String paramString = URLEncodedUtils
.format(params, "utf-8");
url += "?" + paramString;
}
HttpGet httpGet = new HttpGet(url);
// DefaultHttpClient httpClient = new
// DefaultHttpClient(httpParameters);
HttpResponse httpResponse = httpClient.execute(httpGet);
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) {
}
// return JSON String
return json;
}
}
why the output just says :
{"data":[]}
this is my code :
package percobaan;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import org.apache.http.NameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
/**
*
* #author nafian
*/
public class Coba {
public static void main(String[] args) {
ArrayList<HashMap<String, String>> daftar_d = new ArrayList<HashMap<String, String>>();
JSONParser jsonParser = new JSONParser();
String link_url = "http://api.pemiluapi.org/calonpresiden/api/caleg/jk?apiKey=56513c05217f73e6be82d5542368ae4f";
List<NameValuePair> params = new ArrayList<NameValuePair>();
String parsing = jsonParser.makeHttpRequest(link_url, "POST",
params);
System.out.print(parsing);
// try {
// JSONObject json = new JSONObject(parsing).getJSONObject("data").getJSONObject("results");
// JSONArray caleg = json.getJSONArray("caleg");
//
// for (int i = 0; i < caleg.length(); i++) {
// HashMap<String, String> map = new HashMap<String, String>();
// JSONObject ar = caleg.getJSONObject(i);
// String nama = ar.getString("nama");
// String calon = ar.getString("role");
//
// JSONArray riwayat = ar.getJSONArray("riwayat_pendidikan");
// for (int j = 0; j < riwayat.length(); j++) {
// JSONObject ringkasan = riwayat.getJSONObject(j);
// String ringkasan_p = ringkasan.getString("ringkasan");
// map.put("pendidikan_r", ringkasan_p);
// }
//
// map.put("nama", nama);
// map.put("calon", calon);
// daftar_d.add(map);
//
// }
// } catch (JSONException ex) {
// ex.printStackTrace();
// }
// for (int i = 0; i < daftar_d.size(); i++) {
//
// System.out.println(daftar_d.get(i).get("pendidikan_r").toString());
// }
}
}
Am I missing something?

I suggest you use JSON-SIMPLE, it will literally simplify your life.
https://code.google.com/p/json-simple/
Here is a small example for the given URL.
Please note that's I'm using Jersey for establishing the connection, but you can pretty much use anything you like instead.
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
import com.sun.jersey.api.client.Client;
import com.sun.jersey.api.client.ClientHandlerException;
import com.sun.jersey.api.client.ClientResponse;
import com.sun.jersey.api.client.UniformInterfaceException;
import com.sun.jersey.api.client.WebResource;
...
String callString = "http://api.pemiluapi.org/calonpresiden/api/caleg/jk?apiKey=56513c05217f73e6be82d5542368ae4f";
Client client = Client.create();
WebResource webResource = client.resource(callString);
ClientResponse clientResponse = webResource.accept("application/json").get(ClientResponse.class);
if (clientResponse.getStatus() != 200) {
throw new RuntimeException("Failed"+ clientResponse.toString());
}
JSONObject resObj = (JSONObject)new JSONParser().parse(clientResponse.getEntity(String.class));
JSONObject data_obj = (JSONObject) resObj.get("data");
JSONObject results_obj = (JSONObject) data_obj.get("results");
JSONArray caleg_array = (JSONArray) results_obj.get("caleg");

Parsing Twitter API 1.1 JSON

I've been working on an open source code of a Twitter reader (read only) (oauth 2.0) that pulls JSON from a user timeline. It successfully pulls the JSON from Twitter API 1.1. The challenge I'm facing is converting that JSON into something user friendly. I've implemented sections of another source code that focused on parsing the JSON, but I'm not very familiar with parsing JSON. It's patchwork so I know I might be overlooking something. Possibly a redundancy or missing part.
UPDATED:
When I run the app, it doesn't crash, it's just stuck at "Got Token!". What I'm hoping to display is a list of tweets somewhat formatted to look like one. I believe it's the MainActivity, but I could be wrong. You will need a Consumer Key and Secret to test. I'll put up what I have at the moment, but if anyone knows how I can get out of that loop, I'd appreciate your input.
Thanks!
MainActivity.java
package com.example.readtwitterfeed;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.BasicHttpParams;
import org.json.JSONObject;
import org.json.simple.JSONArray;
import org.json.simple.JSONValue;
import android.os.AsyncTask;
import android.os.Bundle;
import android.app.Activity;
import android.util.Base64;
import android.util.Log;
import android.widget.TextView;
import com.example.readtwitterfeed.R;
public class MainActivity extends Activity {
// CONSUMER API KEY - 21 characters (go here to get one: https://dev.twitter.com/apps/)
// **** CHANGE THIS ****
static final String twitterAPIKEY = "################";
// CONSUMER SECRET - 41 characters (go here to get one: https://dev.twitter.com/apps/)
// **** CHANGE THIS ****
static final String twitterAPISECRET = "###############################";
static final String twitterAPIurl = "https://api.twitter.com/1.1/statuses/user_timeline.json?screen_name=";
// Twitter 'Screen Name'
// **** CHANGE THIS ****
static final String screenName = "Insert_Username_Here";
// Tweets to return
// **** CHANGE THIS, if needed ****
static final int tweets2Return = 1;
// Final URL will look like this (# is your sreen name/return tweets):
// https://api.twitter.com/1.1/statuses/user_timeline.json?screen_name=###&include_rts=1&count=#
static String tweeterURL = twitterAPIurl + screenName
+ "&include_rts=1&count=" + tweets2Return;
static String twitterToken = null;
static String jsonTokenStream = null;
static String jsonFeed = null;
static String tweetJSON = null;
TextView twitterText;
// ////////////////////////////////////
// onCreate - Let's get the GUI going
// ////////////////////////////////////
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
twitterText = (TextView) findViewById(R.id.tweetFeed);
// Call first AsyncTask
new loadTwitterToken().execute();
}
// ////////////////////////////////////////////////////////////////////
// AsyncTask - First, let's get our Token for oAuth (from Twitter)
// If you need oAuth help: https://dev.twitter.com/docs/auth/oauth/faq/
// ////////////////////////////////////////////////////////////////////
protected class loadTwitterToken extends AsyncTask<Void, Void, Integer> {
#Override
protected Integer doInBackground(Void... params) {
//As of this writing, Twitter says, "We do not currently expire access tokens."
try {
DefaultHttpClient httpclient = new DefaultHttpClient(
new BasicHttpParams());
HttpPost httppost = new HttpPost(
"https://api.twitter.com/oauth2/token");
String apiString = twitterAPIKEY + ":" + twitterAPISECRET;
String authorization = "Basic "
+ Base64.encodeToString(apiString.getBytes(),
Base64.NO_WRAP);
httppost.setHeader("Authorization", authorization);
httppost.setHeader("Content-Type",
"application/x-www-form-urlencoded;charset=UTF-8");
httppost.setEntity(new StringEntity(
"grant_type=client_credentials"));
InputStream inputStream = null;
// Let's send to web
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
// Our response
inputStream = entity.getContent();
BufferedReader reader = new BufferedReader(
new InputStreamReader(inputStream, "UTF-8"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
// Will look like this:
// {"token_type":"bearer","access_token":"AAAAAAAAAAAAAAAAAAAAABiQTgAAAAAACGie2o%2Bm7jNnxw8txVG99c1wAU8%3DmZq7qrX8JZpDFrgYyh5gLtOkJhQ7BvPD6bZ0ssitjg"}
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
jsonTokenStream = sb.toString();
// onPostExecute likes to get a parameter passed to work right.
// Just passing something.
return 1;
} catch (Exception e) {
Log.e("loadTwitterToken",
"doInBackground Error:" + e.getMessage());
return null;
}
}
#Override
protected void onPostExecute(Integer result) {
// Extract Token from JSON stream
try {
JSONObject root = new JSONObject(jsonTokenStream);
twitterToken = root.getString("access_token");
} catch (Exception e) {
Log.e("loadTwitterToken", "onPost Error:" + e.getMessage());
}
twitterText.setText("Got Token!");
// Now that we have a oAuth Token, lets get our JSON feed from twitter.
// We call it from here to make sure the Token has been received already.
new loadTwitterFeed().execute();
}
}
// ///////////////////////////////////////////////////////////
// AsyncTask - Download Twitter Feed w/Token as authorization
// //////////////////////////////////////////////////////////
protected class loadTwitterFeed extends AsyncTask<Void, Void, Integer> {
#Override
protected Integer doInBackground(Void... params) {
BufferedReader reader =null;
try{
DefaultHttpClient httpclient = new DefaultHttpClient(
new BasicHttpParams());
HttpGet httpget = new HttpGet(tweeterURL);
httpget.setHeader("Authorization", "Bearer " + twitterToken);
httpget.setHeader("Content-type", "application/json");
InputStream inputStream = null;
HttpResponse response = httpclient.execute(httpget);
HttpEntity entity = response.getEntity();
inputStream = entity.getContent();
reader = new BufferedReader(
new InputStreamReader(inputStream, "UTF-8"), 8);
return null;
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally{
if (reader != null)
try {
reader.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return null;
}
protected void onPostExecute(String result) {
StringBuilder sb = new StringBuilder();
try{
JSONObject resultObject = new JSONObject(result);
org.json.JSONArray tweetArray = resultObject.getJSONArray("results");
for (int t=0; t<tweetArray.length(); t++) {
JSONObject tweetObject = tweetArray.getJSONObject(t);
sb.append(tweetObject.getString("from_user")+": ");
sb.append(tweetObject.get("text")+"\n\n");
}
}
catch (Exception e) {
Log.e("Tweet", "Error retrieving JSON stream" + e.getMessage());
jsonFeed = sb.toString();
e.printStackTrace();
}
}
}
/*String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}*/
protected void onPostExecute(Integer result) {
// Update GUI
if (jsonFeed.length() > 0) {
twitterText.setText(jsonFeed);
} else {
//I'd assume wrong Consumer Key/Secret if this happens.
twitterText.setText("Nothing Returned");
}
}
}
Activity_Main.xml
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:id="#+id/tweetFeed"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Loading..." />
</ScrollView>

You forgot to close the ProgressDialog in onPostExecute method.
just do this pd.dismiss(); in onPostExecute like this.
#Override
protected void onPostExecute(Integer result) {
pd.dismiss();
// Extract Token from JSON stream
try {
JSONObject root = new JSONObject(jsonTokenStream);
twitterToken = root.getString("access_token");
} catch (Exception e) {
Log.e("loadTwitterToken", "onPost Error:" + e.getMessage());
}
twitterText.setText("Got Token!");
// Now that we have a oAuth Token, lets get our JSON feed from twitter.
// We call it from here to make sure the Token has been received already.
new loadTwitterFeed().execute();
}

Parsing JSON from URL

Is there any simplest way to parse JSON from a URL? I used Gson I can't find any helpful examples.

First you need to download the URL (as text):
private static String readUrl(String urlString) throws Exception {
BufferedReader reader = null;
try {
URL url = new URL(urlString);
reader = new BufferedReader(new InputStreamReader(url.openStream()));
StringBuffer buffer = new StringBuffer();
int read;
char[] chars = new char[1024];
while ((read = reader.read(chars)) != -1)
buffer.append(chars, 0, read);
return buffer.toString();
} finally {
if (reader != null)
reader.close();
}
}
Then you need to parse it (and here you have some options).
GSON (full example):
static class Item {
String title;
String link;
String description;
}
static class Page {
String title;
String link;
String description;
String language;
List<Item> items;
}
public static void main(String[] args) throws Exception {
String json = readUrl("http://www.javascriptkit.com/"
+ "dhtmltutors/javascriptkit.json");
Gson gson = new Gson();
Page page = gson.fromJson(json, Page.class);
System.out.println(page.title);
for (Item item : page.items)
System.out.println(" " + item.title);
}
Outputs:
javascriptkit.com
Document Text Resizer
JavaScript Reference- Keyboard/ Mouse Buttons Events
Dynamically loading an external JavaScript or CSS file
Try the java API from json.org:
try {
JSONObject json = new JSONObject(readUrl("..."));
String title = (String) json.get("title");
...
} catch (JSONException e) {
e.printStackTrace();
}

GSON has a builder that takes a Reader object: fromJson(Reader json, Class classOfT).
This means you can create a Reader from a URL and then pass it to Gson to consume the stream and do the deserialisation.
Only three lines of relevant code.
import java.io.InputStreamReader;
import java.net.URL;
import java.util.Map;
import com.google.gson.Gson;
public class GsonFetchNetworkJson {
public static void main(String[] ignored) throws Exception {
URL url = new URL("https://httpbin.org/get?color=red&shape=oval");
InputStreamReader reader = new InputStreamReader(url.openStream());
MyDto dto = new Gson().fromJson(reader, MyDto.class);
// using the deserialized object
System.out.println(dto.headers);
System.out.println(dto.args);
System.out.println(dto.origin);
System.out.println(dto.url);
}
private class MyDto {
Map<String, String> headers;
Map<String, String> args;
String origin;
String url;
}
}
If you happen to get a 403 error code with an endpoint which otherwise works fine (e.g. with curl or other clients) then a possible cause could be that the endpoint expects a User-Agent header and by default Java URLConnection is not setting it. An easy fix is to add at the top of the file e.g. System.setProperty("http.agent", "Netscape 1.0");.

You could use org.apache.commons.io.IOUtils for downloading and org.json.JSONTokener for parsing:
JSONObject jo = (JSONObject) new JSONTokener(IOUtils.toString(new URL("http://gdata.youtube.com/feeds/api/videos/SIFL9qfmu5U?alt=json"))).nextValue();
System.out.println(jo.getString("version"));

Here is a easy method.
First parse the JSON from url -
public String readJSONFeed(String URL) {
StringBuilder stringBuilder = new StringBuilder();
HttpClient httpClient = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(URL);
try {
HttpResponse response = httpClient.execute(httpGet);
StatusLine statusLine = response.getStatusLine();
int statusCode = statusLine.getStatusCode();
if (statusCode == 200) {
HttpEntity entity = response.getEntity();
InputStream inputStream = entity.getContent();
BufferedReader reader = new BufferedReader(
new InputStreamReader(inputStream));
String line;
while ((line = reader.readLine()) != null) {
stringBuilder.append(line);
}
inputStream.close();
} else {
Log.d("JSON", "Failed to download file");
}
} catch (Exception e) {
Log.d("readJSONFeed", e.getLocalizedMessage());
}
return stringBuilder.toString();
}
Then place a task and then read the desired value from JSON -
private class ReadPlacesFeedTask extends AsyncTask<String, Void, String> {
protected String doInBackground(String... urls) {
return readJSONFeed(urls[0]);
}
protected void onPostExecute(String result) {
JSONObject json;
try {
json = new JSONObject(result);
////CREATE A JSON OBJECT////
JSONObject data = json.getJSONObject("JSON OBJECT NAME");
////GET A STRING////
String title = data.getString("");
//Similarly you can get other types of data
//Replace String to the desired data type like int or boolean etc.
} catch (JSONException e1) {
e1.printStackTrace();
}
//GETTINGS DATA FROM JSON ARRAY//
try {
JSONObject jsonObject = new JSONObject(result);
JSONArray postalCodesItems = new JSONArray(
jsonObject.getString("postalCodes"));
JSONObject postalCodesItem = postalCodesItems
.getJSONObject(1);
} catch (Exception e) {
Log.d("ReadPlacesFeedTask", e.getLocalizedMessage());
}
}
}
You can then place a task like this -
new ReadPlacesFeedTask()
.execute("JSON URL");

public static TargetClassJson downloadPaletteJson(String url) throws IOException {
if (StringUtils.isBlank(url)) {
return null;
}
String genreJson = IOUtils.toString(new URL(url).openStream());
return new Gson().fromJson(genreJson, TargetClassJson.class);
}

import org.apache.commons.httpclient.util.URIUtil;
import org.apache.commons.io.FileUtils;
import groovy.json.JsonSlurper;
import java.io.File;
tmpDir = "/defineYourTmpDir"
URL url = new URL("http://yourOwnURL.com/file.json");
String path = tmpDir + "/tmpRemoteJson" + ".json";
remoteJsonFile = new File(path);
remoteJsonFile.deleteOnExit();
FileUtils.copyURLToFile(url, remoteJsonFile);
String fileTMPPath = remoteJsonFile.getPath();
def inputTMPFile = new File(fileTMPPath);
remoteParsedJson = new JsonSlurper().parseText(inputTMPFile.text);

I use java 1.8
with com.fasterxml.jackson.databind.ObjectMapper
ObjectMapper mapper = new ObjectMapper();
Integer value = mapper.readValue(new URL("your url here"), Integer.class);
Integer.class can be also a complex type. Just for example used.

A simple alternative solution:
Paste the URL into a json to csv converter
Open the CSV file in either Excel or Open Office
Use the spreadsheet tools to parse the data