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Start intensive POST in background service getting crashes

So there is a background Service which creates Runnable objects as soon as GPS Location is changed. Runnable contains HTTPConnection to make POST and twice send broadcast message via sendBroadcast().
So the problem I am facing if there is no chance to send data by this scheme something happened and app craches.
Any clue to refactor code or may be change approach to TaskAsync and cancel pending TaskAsync when new TaskAsync is ready?
Any clue?
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.location.Location;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.IBinder;
import android.text.format.DateFormat;
import android.util.Log;
import com.google.gson.Gson;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Date;
public class gps_service2 extends Service {
private static final String TAG = "GPS SERVICE";
private LocationManager mLocationManager = null;
private static final int LOCATION_INTERVAL = 10000;
private static final float LOCATION_DISTANCE = 10f;
Context context;
private class LocationListener implements android.location.LocationListener
{
Location mLastLocation;
public LocationListener(String provider)
{
Log.e(TAG, "LocationListener " + provider);
mLastLocation = new Location(provider);
}
#Override
public void onLocationChanged(Location location)
{
Log.e(TAG, "onLocationChanged: " + location);
try
{
ComplexPreferences complexPreferences = ComplexPreferences.getComplexPreferences(context, "App_Settings", 0);
AppSettings appSettings = complexPreferences.getObject("App_Settings", AppSettings.class);
if (appSettings != null) {
LocationItem locationItem = new LocationItem();
locationItem.DeviceID = appSettings.getDeviceID();
locationItem.Latitude = Double.toString(location.getLatitude());
locationItem.Longitude = Double.toString(location.getLongitude());
Date d = new Date();
CharSequence timeOfRequest = DateFormat.format("yyyy-MM-dd HH:mm:ss", d.getTime()); // YYYY-MM-DD HH:mm:ss
locationItem.TimeOfRequest = timeOfRequest.toString();
locationItem.SerialNumber = appSettings.getSerialNumber();
Gson gson = new Gson();
String requestObject = gson.toJson(locationItem);
String url = appSettings.getIpAddress() + "/api/staff/savedata";
makeRequest(url, requestObject, dLocation);
}
}
catch (Exception ex)
{
}
}
#Override
public void onProviderDisabled(String provider)
{
Log.e(TAG, "onProviderDisabled: " + provider);
}
#Override
public void onProviderEnabled(String provider)
{
Log.e(TAG, "onProviderEnabled: " + provider);
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras)
{
Log.e(TAG, "onStatusChanged: " + provider);
}
}
LocationListener[] mLocationListeners = new LocationListener[] {
new LocationListener(LocationManager.GPS_PROVIDER),
new LocationListener(LocationManager.NETWORK_PROVIDER)
};
#Override
public IBinder onBind(Intent arg0)
{
return null;
}
#Override
public int onStartCommand(Intent intent, int flags, int startId)
{
Log.e(TAG, "onStartCommand");
super.onStartCommand(intent, flags, startId);
return START_STICKY;
}
#Override
public void onCreate()
{
context = this;
Log.e(TAG, "onCreate");
initializeLocationManager();
try {
mLocationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER, LOCATION_INTERVAL, LOCATION_DISTANCE,
mLocationListeners[1]);
} catch (java.lang.SecurityException ex) {
Log.i(TAG, "fail to request location update, ignore", ex);
} catch (IllegalArgumentException ex) {
Log.d(TAG, "network provider does not exist, " + ex.getMessage());
}
try {
mLocationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER, LOCATION_INTERVAL, LOCATION_DISTANCE,
mLocationListeners[0]);
} catch (java.lang.SecurityException ex) {
Log.i(TAG, "fail to request location update, ignore", ex);
} catch (IllegalArgumentException ex) {
Log.d(TAG, "gps provider does not exist " + ex.getMessage());
}
}
#Override
public void onDestroy()
{
Log.e(TAG, "onDestroy");
super.onDestroy();
if (mLocationManager != null) {
for (int i = 0; i < mLocationListeners.length; i++) {
try {
mLocationManager.removeUpdates(mLocationListeners[i]);
} catch (Exception ex) {
Log.i(TAG, "fail to remove location listners, ignore", ex);
}
}
}
}
private void initializeLocationManager() {
Log.e(TAG, "initializeLocationManager");
if (mLocationManager == null) {
mLocationManager = (LocationManager) getApplicationContext().getSystemService(Context.LOCATION_SERVICE);
}
}
public static double round(double value, int places) {
if (places < 0) throw new IllegalArgumentException();
BigDecimal bd = new BigDecimal(value);
bd = bd.setScale(places, RoundingMode.HALF_UP);
return bd.doubleValue();
}
public void makeRequest(String uri, String json, DLocation dLocation) {
HandlerThread handlerThread = new HandlerThread("URLConnection");
handlerThread.start();
Handler mainHandler = new Handler(handlerThread.getLooper());
Runnable myRunnable = createRunnable(uri, json, dLocation);
mainHandler.post(myRunnable);
}
private Runnable createRunnable(final String uri, final String data,final DLocation dLocation){
Runnable aRunnable = new Runnable(){
public void run(){
try {
//Connect
HttpURLConnection urlConnection;
urlConnection = (HttpURLConnection) ((new URL(uri).openConnection()));
urlConnection.setDoOutput(true);
urlConnection.setRequestProperty("Content-Type", "application/json");
urlConnection.setRequestProperty("Accept", "application/json");
urlConnection.setRequestMethod("POST");
urlConnection.connect();
//Write
OutputStream outputStream = urlConnection.getOutputStream();
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
try {
writer.write(data);
} catch (IOException e) {
e.printStackTrace();
Log.d(TAG,"Ошибка записи в буфер для пережачи по HTTP");
}
writer.close();
outputStream.close();
//Read
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream(), "UTF-8"));
String line = null;
StringBuilder sb = new StringBuilder();
while ((line = bufferedReader.readLine()) != null) {
sb.append(line);
}
bufferedReader.close();
String result = sb.toString();
Log.d(TAG, result);
Intent iResult = new Intent("location_update");
DLocation dLocation = new DLocation();
iResult.putExtra("result", dLocation);
sendBroadcast(iResult);
}catch( Exception err){
err.printStackTrace();
Log.d(TAG, "HTTP " + err.getMessage());
}
}
};
return aRunnable;
}
}

Runnable is just an interface, when you create a thread using Runnable interface basically it will run under the the thread where it created, in here runnable associate with UI thread, as per google documentation Network calls must be in a worker thread not in UI thread.
Then Why it runs on emulator
android had DVM(dalvik virtual machine),it works like JVM but instead of .class file DVM uses .dex extension, so may the device had older or newer version of DVM.
Fix
Use android's AsyncTask for network calls. android(DVM) had limited resources compare to JVM, when it comes to thread, so better use AsyncTask
check this answer too
AsyncTask code for passing JSON to server, and get responds as callback
public class WebService extends AsyncTask<String,String,String> {
private static final String TAG="SyncToServerTAG";
private String urlString;
private JSONObject jsonObject=null;
private int screenId=1;
public WebService(String url) {
this.urlString=url;
}
public WebService(Context context, String url, JSONObject jsonObject) {
this.urlString = url;
this.jsonObject = jsonObject;
}
#Override
protected String doInBackground(String... strings) {
try {
URL url = new URL(urlString);
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setChunkedStreamingMode(0);
urlConnection.setConnectTimeout(5000);
urlConnection.setRequestProperty("Content-Type", "application/json; charset=UTF-8");
urlConnection.setDoOutput(true);
urlConnection.setDoInput(true);
urlConnection.setRequestMethod("POST");
if(jsonObject!=null) {
OutputStream os = urlConnection.getOutputStream();
os.write(jsonObject.toString().getBytes("UTF-8"));
}
InputStream in = new BufferedInputStream(urlConnection.getInputStream());
BufferedReader br = new BufferedReader(new InputStreamReader(
(urlConnection.getInputStream())));
String output="";
while (true) {
String line=br.readLine();
Log.d(TAG,line+" ");
if(line!=null)
output+=line;
else
break;
}
in.close();
urlConnection.disconnect();
JSONObject j;
if(output.equals(""))
publishProgress("Server give null");
else {
j=new JSONObject(output);
return output;
}
return output;
} catch (MalformedURLException e) {
e.printStackTrace();
publishProgress(e.toString());
} catch (IOException e) {
e.printStackTrace();
publishProgress(e.toString());
} catch (JSONException e) {
e.printStackTrace();
publishProgress(e.toString());
}
return null;
}
#Override
protected void onProgressUpdate(String... values) {
super.onProgressUpdate(values);
fireError(values[0]);
}
#Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
if(s!=null) {
try {
JSONObject jsonObject=new JSONObject(s);
fireComplete(0, jsonObject);
} catch (JSONException e) {
e.printStackTrace();
fireError("Non acceptable responds from server ["+urlString+"]");
}
}
}
public interface OnWebCompleteListener{
void onComplete(JSONObject result, int dataSource);
void onError(String error);
}
private OnWebCompleteListener onWebCompleteListener;
private void fireComplete(int sourse,JSONObject cache){
if(onWebCompleteListener!=null)
onWebCompleteListener.onComplete(cache,sourse);
}
private void fireError(String message){
if(onWebCompleteListener!=null)
onWebCompleteListener.onError(message);
}
public void start(OnWebCompleteListener onWebCompleteListener){
if(onWebCompleteListener==null)
throw new RuntimeException("You must provide non-null value as start listener");
this.onWebCompleteListener=onWebCompleteListener;
execute((String)null);
}
}
Usage
WebService webService=new WebService(context,"url",jsonObject);
webService.start(new WebService.OnWebCompleteListener() {
#Override
public void onComplete(JSONObject result, int dataSource) {
}
#Override
public void onError(String error) {
}
});

Your code is very vulnerable. I think that you crash because your makeRequest method exits before you Runnable had the chance to complete the task.
You closed the resource as soon as you send them, freeing system resources.
There for the second time you call broadcast, the resources are not there anymore causing the crash....

Android JSON Parsing - End of input at character 0 of error

This is my first time making an android application that parses JSON data.
However, I'm encountering an error regarding JSON parsing. I've tried Googling the problem but most of the solutions didn't work for me.
Here are my codes:
MainActivity.java
package com.example.jsonparser;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.util.Log;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;
public class MainActivity extends AppCompatActivity {
private String TAG = MainActivity.class.getSimpleName();
private ProgressDialog pDialog;
private ListView lv;
// URL to get contacts JSON
private static String url = "http://pastebin.com/raw/79D93HR4";
ArrayList<HashMap<String, String>> itemList;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
itemList = new ArrayList<>();
lv = (ListView) findViewById(R.id.list);
new GetItems().execute();
}
/**
* Async task class to get json by making HTTP call
*/
private class GetItems extends AsyncTask<Void, Void, Void> {
#Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(MainActivity.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
#Override
protected Void doInBackground(Void... arg0) {
HttpHandler sh = new HttpHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url);
Log.e(TAG, "Response from url: " + jsonStr);
if (jsonStr != null) {
try {
//JSONObject jsonObj = new JSONObject(jsonStr);
// Getting JSON Array node
JSONArray items = new JSONArray("");
// looping through All Contacts
for (int i = 0; i < items.length(); i++) {
JSONObject c = items.getJSONObject(i);
String ItemCode = c.getString("ItemCode");
String ItemName = c.getString("ItemName");
// tmp hash map for single item
HashMap<String, String> item = new HashMap<>();
// adding each child node to HashMap key => value
item.put("ItemCode", ItemCode);
item.put("ItemName", ItemName);
// adding item to item list
itemList.add(item);
}
} catch (final JSONException e) {
Log.e(TAG, "Json parsing error: " + e.getMessage());
runOnUiThread(new Runnable() {
#Override
public void run() {
Toast.makeText(getApplicationContext(),
"Json parsing error: " + e.getMessage(),
Toast.LENGTH_LONG)
.show();
}
});
}
} else {
Log.e(TAG, "Couldn't get json from server.");
runOnUiThread(new Runnable() {
#Override
public void run() {
Toast.makeText(getApplicationContext(),
"Couldn't get json from server. Check LogCat for possible errors!",
Toast.LENGTH_LONG)
.show();
}
});
}
return null;
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
MainActivity.this, itemList,
R.layout.list_item, new String[]{"ItemCode", "ItemName"}, new int[]{R.id.ItemCode,
R.id.ItemName});
lv.setAdapter(adapter);
}
}
}
HttpHandler.java
package com.example.jsonparser;
/**
* Created by Me on 1/3/2017.
*/
import android.util.Log;
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.ProtocolException;
import java.net.URL;
public class HttpHandler {
private static final String TAG = HttpHandler.class.getSimpleName();
public HttpHandler() {
}
public String makeServiceCall(String reqUrl) {
String response = null;
try {
URL url = new URL(reqUrl);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("GET");
// read the response
InputStream in = new BufferedInputStream(conn.getInputStream());
response = convertStreamToString(in);
} catch (MalformedURLException e) {
Log.e(TAG, "MalformedURLException: " + e.getMessage());
} catch (ProtocolException e) {
Log.e(TAG, "ProtocolException: " + e.getMessage());
} catch (IOException e) {
Log.e(TAG, "IOException: " + e.getMessage());
} catch (Exception e) {
Log.e(TAG, "Exception: " + e.getMessage());
}
return response;
}
private String convertStreamToString(InputStream is) {
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line;
try {
while ((line = reader.readLine()) != null) {
sb.append(line).append('\n');
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return sb.toString();
}
}
And here is the error code:
01-04 00:13:05.366 10069-10112/com.example.jsonparser E/MainActivity: Response from url: [{"ItemCode":"C0100001 ","ItemName":"UBNT CRM-P-CRM Point","LocationCode":null,"ViewBy":null,"SearchDate":null,"CutOffDate":"\/Date(-62135596800000)\/","CurrentDate":"\/Date(-62135596800000)\/"},{"ItemCode":"C0100002 ","ItemName":"UBNT ETH-SP-Ethernet Surge Protector","LocationCode":null,"ViewBy":null,"SearchDate":null,"CutOffDate":"\/Date(-62135596800000)\/","CurrentDate":"\/Date(-62135596800000)\/"}]
01-04 00:13:05.367 10069-10112/com.example.jsonparser E/MainActivity: Json parsing error: End of input at character 0 of
What am I doing wrong?

JSONArray need a json string. Pass your json in JSONArray initialize
JSONArray items = new JSONArray(jsonStr );

JSONArray items = new JSONArray("");
You're passing in an empty string to convert from json. Since there's no data in the string, its failing at character 0 with invalid input (the input isn't valid JSON).

How to display JSONObject into TextView on android

I've set up a php script to create json here, but when i try to display the JSONobject i got some error like this on my Android Monitor..
Value (html)(body)(script of type java.lang.String cannot be converted to JSONObject
can someone tell me how to fix it? below my code to try
my MainActivity.java
package flix.yudi.okhttp1;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;
public class MainActivity extends AppCompatActivity {
private String TAG = MainActivity.class.getSimpleName();
private ProgressDialog pDialog;
private ListView lv;
// URL to get contacts JSON
private static String url = "http://zxccvvv.cuccfree.com/send_data.php";
ArrayList<HashMap<String, String>> contactList;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
contactList = new ArrayList<>();
lv = (ListView) findViewById(R.id.list);
new GetContacts().execute();
}
/**
* Async task class to get json by making HTTP call
*/
private class GetContacts extends AsyncTask<Void, Void, Void> {
#Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(MainActivity.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
#Override
protected Void doInBackground(Void... arg0) {
HttpHandler sh = new HttpHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url);
Log.e(TAG, "Response from url: " + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
// Getting JSON Array node
JSONArray contacts = jsonObj.getJSONArray("");
// looping through All Contacts
for (int i = 0; i < contacts.length(); i++) {
JSONObject c = contacts.getJSONObject(i);
String id = c.getString("id");
String ask = c.getString("ask");
// tmp hash map for single contact
HashMap<String, String> contact = new HashMap<>();
// adding each child node to HashMap key => value
contact.put("id", id);
contact.put("ask", ask);
// adding contact to contact list
contactList.add(contact);
}
} catch (final JSONException e) {
Log.e(TAG, "Json parsing error: " + e.getMessage());
runOnUiThread(new Runnable() {
#Override
public void run() {
Toast.makeText(getApplicationContext(),
"Json parsing error: " + e.getMessage(),
Toast.LENGTH_LONG)
.show();
}
});
}
} else {
Log.e(TAG, "Couldn't get json from server.");
runOnUiThread(new Runnable() {
#Override
public void run() {
Toast.makeText(getApplicationContext(),
"Couldn't get json from server. Check LogCat for possible errors!",
Toast.LENGTH_LONG)
.show();
}
});
}
return null;
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
MainActivity.this, contactList,
R.layout.list_item, new String[]{"ask"}, new int[]{R.id.ask});
lv.setAdapter(adapter);
}
}
}
my HttpHandler.java
package flix.yudi.okhttp1;
import android.util.Log;
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.ProtocolException;
import java.net.URL;
public class HttpHandler {
private static final String TAG = HttpHandler.class.getSimpleName();
public HttpHandler() {
}
public String makeServiceCall(String reqUrl) {
String response = null;
try {
URL url = new URL(reqUrl);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("GET");
// read the response
InputStream in = new BufferedInputStream(conn.getInputStream());
response = convertStreamToString(in);
} catch (MalformedURLException e) {
Log.e(TAG, "MalformedURLException: " + e.getMessage());
} catch (ProtocolException e) {
Log.e(TAG, "ProtocolException: " + e.getMessage());
} catch (IOException e) {
Log.e(TAG, "IOException: " + e.getMessage());
} catch (Exception e) {
Log.e(TAG, "Exception: " + e.getMessage());
}
return response;
}
private String convertStreamToString(InputStream is) {
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line;
try {
while ((line = reader.readLine()) != null) {
sb.append(line).append('\n');
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return sb.toString();
}
}
I got the reference code from here
someone can help me how to fix the error?
Edited code
if (jsonStr != null) {
try {
JSONArray jsonObj = new JSONArray(jsonStr);
// Getting JSON Array node
JSONArray pertanyaan = jsonObj.getJSONArray("pertanyaan");
// looping through All Contacts
for (int i = 0; i < pertanyaan.length(); i++) {
JSONArray c = pertanyaan.getJSONArray(i);
String id = c.getString("id");
String ask = c.getString("ask");
Edit
Error
I/OpenGLRenderer: Initialized EGL, version 1.4
E/MainActivity: Response from url: <html><body><script type="text/javascript" src="/aes.js" ></script>
<script>function toNumbers(d){var e=[];d.replace(/(..)/g,function(d){e.push(parseInt(d,16))});return e}function
toHex(){for(var d=[],d=1==arguments.length&&arguments[0].constructor==Array?arguments[0]:arguments,e="",f=0;f<d.length;f++)e+=(16>d[f]?"0":"")+d[f].toString(16);return e.toLowerCase()}
var a=toNumbers("f655ba9d09a112d4968c63579db590b4"),b=toNumbers("98344c2eee86c3994890592585b49f80"),c=toNumbers("455e95bd78dbe99a933749187199f824");
document.cookie="__test="+toHex(slowAES.decrypt(c,2,a,b))+"; expires=Thu, 31-Dec-37 23:55:55 GMT; path=/";
location.href="http://zxccvvv.cuccfree.com/send_data.php?i=1";</script><noscript>This site requires Javascript to work, please enable Javascript in your browser or use a browser with Javascript support</noscript></body></html>
E/MainActivity: Json parsing error: Value <html><body><script of type java.lang.String cannot be converted to JSONArray
V/RenderScript: 0x5598622250 Launching thread(s), CPUs 8

If you have access to server then you could make it return a string in the following format:
{"contacts":[{"id":"1","ask":"pertanyaan ke 1"},{"id":"2","ask":"pertanyaan ke 2"},{"id":"3","ask":"pertanyaan ke 3"},{"id":"4","ask":"pertanyaan ke 4"},{"id":"5","ask":"pertanyaan ke 5"}]}
if you want to read it as JSONObject with JSONObject jsonObj = new JSONObject(jsonStr);
and then use JSONArray contacts = jsonObj.getJSONArray("contacts"); to parse it
After your edits:
Change this JSONArray c = pertanyaan.getJSONArray(i); to this JSONObject c = pertanyaan.getJsonObject(i)

Your server response is JsonArray But your trying to parse as Json Object
Change
JSONObject jsonObject = new JSONObject(jsonStr);
To
JSONArray contacts = new JSONArray(jsonStr);
And create the next oprations as JSONArray and not as JSONObject

Android read json from restful service

I am trying to get a response from a service (the response comes in json).
I made my checks if the device is connected and now I need to make the http request to the service. I found out on other questions that I have to use a background thread but I am not sure I got a working sample.
So I need to find out how I can make a connection to a given uri and read the response.
My service needs to get a content header application/json in orderto return a json, so before the request I need to set this header as well.
Thank you in advance
UPDATE
package com.example.restfulapp;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.AsyncTask;
import android.os.Bundle;
import android.app.Activity;
import android.provider.Settings;
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.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.concurrent.ExecutionException;
public class MainActivity extends Activity {
private int code = 0;
private String value = "";
private ProgressDialog mDialog;
private Context mContext;
private String mUrl ="http://192.168.1.13/myservice/upfields/";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (!isOnline())
{
displayNetworkOption ("MyApp", "Application needs network connectivity. Connect now?");
}
try {
JSONObject s = getJSON(mUrl);
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
}
public class Get extends AsyncTask<Void, Void, String> {
#Override
protected String doInBackground(Void... arg) {
String linha = "";
String retorno = "";
mDialog = ProgressDialog.show(mContext, "Please wait", "Loading...", true);
HttpClient client = new DefaultHttpClient();
HttpGet get = new HttpGet(mUrl);
try {
HttpResponse response = client.execute(get);
StatusLine statusLine = response.getStatusLine();
int statusCode = statusLine.getStatusCode();
if (statusCode == 200) { // Ok
BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
while ((linha = rd.readLine()) != null) {
retorno += linha;
}
}
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return retorno;
}
#Override
protected void onPostExecute(String result) {
mDialog.dismiss();
}
}
public JSONObject getJSON(String url) throws InterruptedException, ExecutionException {
setUrl(url);
Get g = new Get();
return createJSONObj(g.get());
}
private void displayNetworkOption(String title, String message){
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder
.setTitle(title)
.setMessage(message)
.setPositiveButton("Wifi", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
startActivity(new Intent(Settings.ACTION_WIFI_SETTINGS));
}
})
.setNeutralButton("Data", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
startActivity(new Intent(Settings.ACTION_DATA_ROAMING_SETTINGS));
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
return;
}
})
.show();
}
private boolean isOnline() {
ConnectivityManager cm =
(ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo netInfo = cm.getActiveNetworkInfo();
if (netInfo != null && netInfo.isConnectedOrConnecting()) {
return true;
}
return false;
}
}
This throws errors:
Gradle: cannot find symbol method setUrl(java.lang.String)
Gradle: cannot find symbol method createJSONObj(java.lang.String)

After derogatory responses from EvZ who think that he was born knowing everything, I ended up with a subclass MyTask that I call like this inside the onCreate of my Activity.
new MyTask().execute(wserviceURL);
private class MyTask extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... urls) {
URL myurl = null;
try {
myurl = new URL(urls[0]);
} catch (MalformedURLException e) {
e.printStackTrace();
}
URLConnection connection = null;
try {
connection = myurl.openConnection();
} catch (IOException e) {
e.printStackTrace();
}
connection.setConnectTimeout(R.string.TIMEOUT_CONNECTION);
connection.setReadTimeout(R.string.TIMEOUT_CONNECTION);
HttpURLConnection httpConnection = (HttpURLConnection) connection;
httpConnection.setRequestProperty("Content-Type", getString(R.string.JSON_CONTENT_TYPE));
int responseCode = -1;
try {
responseCode = httpConnection.getResponseCode();
} catch (SocketTimeoutException ste) {
ste.printStackTrace();
}
catch (Exception e1) {
e1.printStackTrace();
}
if (responseCode == HttpURLConnection.HTTP_OK) {
StringBuilder answer = new StringBuilder(100000);
BufferedReader in = null;
try {
in = new BufferedReader(new InputStreamReader(httpConnection.getInputStream()));
} catch (IOException e) {
e.printStackTrace();
}
String inputLine;
try {
while ((inputLine = in.readLine()) != null) {
answer.append(inputLine);
answer.append("\n");
}
} catch (IOException e) {
e.printStackTrace();
}
try {
in.close();
} catch (IOException e) {
e.printStackTrace();
}
httpConnection.disconnect();
return answer.toString();
}
else
{
//connection is not OK
httpConnection.disconnect();
return null;
}
}
#Override
protected void onPostExecute(String result) {
String userid = null;
String username = null;
String nickname = null;
if (result!=null)
{
try {
//do read the JSON here
} catch (JSONException e) {
e.printStackTrace();
}
}
//stop loader dialog
mDialog.dismiss();
}
}
lory105's answer guided me to somewhere near the answer, thanx.

here is an example of how to process the HTTP response and convert to JSONObject:
/**
* convert the HttpResponse into a JSONArray
* #return JSONObject
* #param response
* #throws IOException
* #throws IllegalStateException
* #throws UnsupportedEncodingException
* #throws Throwable
*/
public static JSONObject processHttpResponse(HttpResponse response) throws UnsupportedEncodingException, IllegalStateException, IOException {
JSONObject top = null;
StringBuilder builder = new StringBuilder();
try {
BufferedReader reader = new BufferedReader(
new InputStreamReader(response.getEntity().getContent(), "UTF-8"));
for (String line = null; (line = reader.readLine()) != null;) {
builder.append(line).append("\n");
}
String decoded = new String(builder.toString().getBytes(), "UTF-8");
Log.d(TAG, "decoded http response: " + decoded);
JSONTokener tokener = new JSONTokener(Uri.decode(builder.toString()));
top = new JSONObject(tokener);
} catch (JSONException t) {
Log.w(TAG, "<processHttpResponse> caught: " + t + ", handling as string...");
} catch (IOException e) {
Log.e(TAG, "caught: " + e, e);
} catch (Throwable t) {
Log.e(TAG, "caught: " + t, t);
}
return top;
}

From Android 3+, the http connections must be done within a separate thread. Android offers a Class named AsyncTask that help you do it.
Here you can find a good example of an AsyncTask that performs an http request and receives a JSON response.
Remember that in the doInBackgroud(..) method you CAN'T modify the UI such as to launch a Toast, to change activity or others. You have to use the onPreExecute() or onPostExecute() methods to do this.
ADD
For the mDialog and mContext variables, add the code below, and when you create the JSONTask write new JSONTask(YOUR_ACTIVITY)
public abstract class JSONTask extends AsyncTask<String, Void, String> {
private Context context = null;
ProgressDialog mDialog = new ProgressDialog();
public JSONTask(Context _context){ context=_context; }
..

Start Activity from Class in new Thread

Basically the idea is I check to see if the web session is still valid, if not I start the main activity which logs the user in automatically.
I have this working, not sure if it's the best way to do it. If anyone has a better way please let me know.
Thanks
Useage:
#Override
public void onResume() {
super.onResume();
new LoginCheck(this,new Intent(this,MyActivity.class));
}
The Class
public class LoginCheck extends Application {
Intent home;
Activity activity;
public LoginCheck(Activity activity, Intent home) {
this.activity = activity;
this.home = home;
new Check().execute();
}
public class Check extends AsyncTask {
#Override
protected Object doInBackground(Object... objects) {
try {
InputStream is = null;
String result = "";
JSONObject jArray = null;
PersistentCookieStore myCookieStore = new PersistentCookieStore(MyApp.getAppContext());
//http post
DefaultHttpClient mClient = AppSettings.getClient();
try {
HttpPost request = new HttpPost(MyApp.getServiceUrl() + "/Api/Login/AmILoggedIn");
mClient.setCookieStore(myCookieStore);
HttpResponse response = mClient.execute(request);
HttpEntity entity = response.getEntity();
is = entity.getContent();
} catch (Exception e) {
Log.e("log_tag", "Error in http connection " + e.toString());
}
//convert response to string
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();
result = sb.toString();
} catch (Exception e) {
Log.e("log_tag", "Error converting result " + e.toString());
}
final String r = result;
final Intent i = home;
activity.runOnUiThread(new Runnable() {
#Override
public void run() {
try {
JSONObject j = new JSONObject(r);
if (!j.getBoolean("Success")) {
try {
activity.startActivity(i);
} catch (Exception e) {
Log.e("log_tag", e.getMessage());
}
}
} catch (JSONException e) {
Log.e("log_tag", "Error parsing data " + e.toString());
}
}
});
return true;
} catch (Exception e) {
}
return null;
}
}
}

Here is the cleaned up version
Use:
new LoginCheck() {
#Override
public void LoggedIn() {
//To change body of implemented methods use File | Settings | File Templates.
}
#Override
public void LoggedOut() {
//To change body of implemented methods use File | Settings | File Templates.
}
};
Class
public abstract class LoginCheck {
public LoginCheck(){
new Check().execute(true);
}
public class Check extends AsyncTask<Boolean,Boolean,Boolean>{
#Override
protected Boolean doInBackground(Boolean... objects) {
JSONStringer jsonSend = null;
try {
jsonSend = new JSONStringer()
.object()
.endObject();
} catch (JSONException e) {
Log.e("log_tag", "Error creating Json " + e.toString());
}
JSONObject result = JsonPost.postJSONtoURL(MyApp.getServiceUrl() + "/Api/Login/AmILoggedIn", jsonSend);
try {
if (result.getBoolean("Success")) {
return true;
}
} catch (JSONException e) {
Log.e("log_tag", "Error parsing data " + e.toString());
}
try {
if (!result.getBoolean("Success")) {
return false;
}
} catch (JSONException e) {
Log.e("log_tag", "Error parsing data " + e.toString());
}
return false;
}
#Override
protected void onPostExecute(Boolean result){
if(result)
LoggedIn();
if(!result)
LoggedOut();
}
}
public abstract void LoggedIn();
public abstract void LoggedOut();
}