Возвращенный JSONObject всегда равен нулю.

Я разрабатываю приложение для Android, которое отправляет имя пользователя и пароль в базу данных MySQL и получает ответ («успех» или «ошибка») в активности входа. Но возвращаемый объект JSONObject имеет значение NULL. Ниже приведены коды

userauth.php

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<?php //Connecting to mysql db include("db.php"); //Check for POST request //if(isset($_POST['tag']) && $_POST['tag'] !=''){ //Get tag // $tag = $_POST['tag']; //} //Getting username and password from android via JSON $username = $_POST['username']; $password = $_POST['password']; //Creating respose array $respose = array("tag" => $tag, "success" => 1, "error" =>0); //Getting data from json //$username='asanka102'; //$password='asanka102'; //Querying mysql database against userauth table for user auth $sql = "SELECT * FROM userauth WHERE username='$username' AND password='$password'"; $qry = mysql_query($sql); $fin_result = mysql_num_rows($qry); //Returning true when user exists & return false when user doen's exist //if$fin_result > 0(){ // return true; //}else{ // return false; //} if($fin_result > 0){ //User found, login should be granted $response["success"] = 1; echo json_encode($response); }else{ //User not found, login shold be prohibited $response["error"] = 0; $response["error_msg"] = 'Invalid login'; echo json_encode($response); } ?> 

MainActivity.java

 public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); etUsername = (EditText) findViewById(R.id.et_username); etPass = (EditText) findViewById(R.id.et_password); errorTxt = (TextView) findViewById(R.id.text_invalid_input); loginButton = (Button) findViewById(R.id.button_login); loginButton.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub new GetPassword().execute(); } }); } private class GetPassword extends AsyncTask<Void, Void, Void> { @Override protected Void doInBackground(Void... arg0) { String username = etUsername.getText().toString(); String password = etPass.getText().toString(); UserFunctions userFunctions = new UserFunctions(); JSONObject json = userFunctions.loginUser(username, password); //Do other things return null; } @Override protected void onPostExecute(Void result) { // TODO Auto-generated method stub if (pDialog.isShowing()) pDialog.dismiss(); } } 

UserFunctions.java

 public class UserFunctions { private JSONParser jsonParser; private static String login_url = "http://192.168.100.172/android/userauth.php"; public UserFunctions(){ jsonParser = new JSONParser(); } /** * function make Login Request * @param username * @param password * */ public JSONObject loginUser(String username, String password){ // Building Parameters List<NameValuePair> params = new ArrayList<NameValuePair>(); params.add(new BasicNameValuePair("username", username)); params.add(new BasicNameValuePair("password", password)); JSONObject json = jsonParser.getJSONFromUrl(login_url, params); // return json // Log.e("JSON", json.toString()); return json; } } 

JSONParser.java

 public class JSONParser { static InputStream is = null; static JSONObject jObj = null; static String json = ""; // constructor public JSONParser() { // Empty constructor } // function get json from url // by making HTTP POST or GET mehtod 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 sb = new StringBuilder(); String line = null; while ((line = reader.readLine()) != null) { sb.append(line + "n"); } is.close(); json = sb.toString(); Log.e("JSON", json); } 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; } } 

Локатор дает это

 02-11 12:29:10.457: E/Buffer Error(13927): Error converting result java.lang.NullPointerException: lock == null 02-11 12:29:10.457: E/JSON Parser(13927): Error parsing data org.json.JSONException: End of input at character 0 of 02-11 12:29:10.457: W/dalvikvm(13927): threadid=11: thread exiting with uncaught exception (group=0x41ba5ba8) 02-11 12:29:10.467: D/dalvikvm(13927): GC_FOR_ALLOC freed 280K, 2% free 17142K/17456K, paused 10ms, total 11ms 02-11 12:29:10.477: E/AndroidRuntime(13927): FATAL EXCEPTION: AsyncTask #1 02-11 12:29:10.477: E/AndroidRuntime(13927): Process: collector.lbfinance, PID: 13927 02-11 12:29:10.477: E/AndroidRuntime(13927): java.lang.RuntimeException: An error occured while executing doInBackground() 02-11 12:29:10.477: E/AndroidRuntime(13927): at android.os.AsyncTask$3.done(AsyncTask.java:300) 02-11 12:29:10.477: E/AndroidRuntime(13927): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355) 02-11 12:29:10.477: E/AndroidRuntime(13927): at java.util.concurrent.FutureTask.setException(FutureTask.java:222) 02-11 12:29:10.477: E/AndroidRuntime(13927): at java.util.concurrent.FutureTask.run(FutureTask.java:242) 02-11 12:29:10.477: E/AndroidRuntime(13927): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231) 02-11 12:29:10.477: E/AndroidRuntime(13927): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) 02-11 12:29:10.477: E/AndroidRuntime(13927): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) 02-11 12:29:10.477: E/AndroidRuntime(13927): at java.lang.Thread.run(Thread.java:841) 02-11 12:29:10.477: E/AndroidRuntime(13927): Caused by: java.lang.NullPointerException 02-11 12:29:10.477: E/AndroidRuntime(13927): at collector.lbfinance.MainActivity$GetPassword.doInBackground(MainActivity.java:102) 02-11 12:29:10.477: E/AndroidRuntime(13927): at collector.lbfinance.MainActivity$GetPassword.doInBackground(MainActivity.java:1) 02-11 12:29:10.477: E/AndroidRuntime(13927): at android.os.AsyncTask$2.call(AsyncTask.java:288) 02-11 12:29:10.477: E/AndroidRuntime(13927): at java.util.concurrent.FutureTask.run(FutureTask.java:237) 02-11 12:29:10.477: E/AndroidRuntime(13927): ... 4 more 

 try { BufferedReader reader = new BufferedReader(new InputStreamReader( is, "utf-8"), 8); StringBuilder sb = new StringBuilder(); String line = null; while ((line = reader.readLine()) != null) { sb.append(line + "\n"); } is.close(); json = sb.toString(); Log.e("JSON", json); } 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;