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POAndroid-Json parser not able to display data retrieved from back end
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  1. POAndroid-Json parser not able to display data retrieved from back end
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    copied!<p>I am new to android. I am implementing a project in which I want to get the data from the back end and display on my android screen.</p> <p>The Json I am trying to call is:-</p> <pre><code>[{"admin":null,"card_no":"8789","created_at":"2013-04-09T12:55:54Z","deleted":0,"email":"dfds@fgfd.com","entered_by":null,"first_name":"Gajanan","id":8,"last_name":"Bhat","last_updated_by":null,"middle_name":"","mobile":87981,"updated_at":"2013-04-13T05:26:25Z","user_type_id":null},{"admin":{"created_at":"2013-04-10T09:02:00Z","deleted":0,"designation":"Sr software Engineer","email":"admin@qwe.com","first_name":"Chiron","id":1,"last_name":"Synergies","middle_name":"Sr software Engineer","office_phone":"98789765","super_admin":false,"updated_at":"2013-04-10T12:03:04Z","username":"Admin"},"card_no":"66","created_at":"2013-04-08T09:47:15Z","deleted":0,"email":"rajaarun1991","entered_by":1,"first_name":"Arun","id":1,"last_name":"Raja\n","last_updated_by":1,"middle_name":"Nagaraj","mobile":941,"updated_at":"2013-04-08T09:47:15Z","user_type_id":1}] </code></pre> <p>My JsonParser.java is as follows:-</p> <pre><code>package com.example.library; 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.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.apache.http.util.EntityUtils; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import android.util.Log; import android.util.Log; public class JSONParser { static InputStream is = null; static JSONArray jarray = null; static String json = ""; // constructor public JSONParser() { } public JSONArray getJSONFromUrl(String url) { StringBuilder builder = new StringBuilder(); HttpClient client = new DefaultHttpClient(); HttpGet httpGet = new HttpGet(url); try { HttpResponse response = client.execute(httpGet); 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); } } else { Log.e("==&gt;", "Failed to download file"); } } catch (ClientProtocolException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } // try parse the string to a JSON object try { jarray = new JSONArray( builder.toString()); } catch (JSONException e) { Log.e("JSON Parser", "Error parsing data " + e.toString()); } // return JSON String return jarray; } } /* public void writeJSON() { JSONObject object = new JSONObject(); try { object.put("name", ""); object.put("score", new Integer(200)); object.put("current", new Double(152.32)); object.put("nickname", "Programmer"); } catch (JSONException e) { e.printStackTrace(); } System.out.println(object); } */ </code></pre> <p>And my activity.java is as follows:-</p> <pre><code>package com.example.library; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import android.app.Activity; import android.app.ListActivity; import android.app.ProgressDialog; import android.content.Context; import android.os.AsyncTask; import android.os.Bundle; import android.util.Log; import android.widget.ListAdapter; import android.widget.ListView; import android.widget.SimpleAdapter; public class SecondActivity extends Activity { private Context context; private static String url = "http://192.168.0.100:3000/users.json"; private static final String TAG_ID = "id"; private static final String TAG_FIRST_NAME = "first_name"; private static final String TAG_MIDDLE_NAME = "middle_name"; private static final String TAG_LAST_NAME = "last_name"; // private static final String TAG_POINTS = "experiencePoints"; ArrayList&lt;HashMap&lt;String, String&gt;&gt; jsonlist = new ArrayList&lt;HashMap&lt;String, String&gt;&gt;(); ListView lv ; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); new ProgressTask(SecondActivity.this).execute(); } private class ProgressTask extends AsyncTask&lt;String, Void, Boolean&gt; { private ProgressDialog dialog; public ProgressTask(SecondActivity secondActivity) { Log.i("1", "Called"); context = secondActivity; dialog = new ProgressDialog(context); } /** progress dialog to show user that the backup is processing. */ /** application context. */ private Context context; protected void onPreExecute() { this.dialog.setMessage("Progress start"); this.dialog.show(); } @Override protected void onPostExecute(final Boolean success) { if (dialog.isShowing()) { dialog.dismiss(); } ListAdapter adapter = new SimpleAdapter(context, jsonlist, R.layout.list_item, new String[] { TAG_ID, TAG_FIRST_NAME, TAG_MIDDLE_NAME, TAG_LAST_NAME }, new int[] { R.id.id, R.id.first_name, R.id.middle_name, R.id.last_name }); setListAdapter(adapter); // selecting single ListView item lv = getListView(); } private void setListAdapter(ListAdapter adapter) { // TODO Auto-generated method stub } protected Boolean doInBackground(final String... args) { JSONParser jParser = new JSONParser(); // getting JSON string from URL JSONArray json = jParser.getJSONFromUrl(url); for (int i = 0; i &lt; json.length(); i++) { try { JSONObject c = json.getJSONObject(i); String id = c.getString(TAG_ID); String first_name = c.getString(TAG_FIRST_NAME); String middle_name = c.getString(TAG_MIDDLE_NAME); String last_name = c.getString(TAG_LAST_NAME); HashMap&lt;String, String&gt; map = new HashMap&lt;String, String&gt;(); // adding each child node to HashMap key =&gt; value map.put(TAG_ID, id); map.put(TAG_FIRST_NAME, first_name); map.put(TAG_MIDDLE_NAME, middle_name); map.put(TAG_LAST_NAME, last_name); jsonlist.add(map); } catch (JSONException e) { // TODO Auto-generated catch block e.printStackTrace(); } } return null; } } public ListView getListView() { // TODO Auto-generated method stub return null; } } </code></pre> <p><img src="https://i.stack.imgur.com/14gla.jpg" alt="Users screen Not giving/showing any output"></p> <p>I am not able to show anything on the emulators for users,whereas I am able to fetch the data from the server</p> <p>Actually in the project I want to display all the users present in the library.I am accessing the server which is on Ubuntu.</p> <p>The following message is displayed on the console(Terminal):-</p> <pre><code>Started GET "/users.json" for 192.168.0.104 at 2013-05-05 22:05:01 -0700 Processing by UsersController#index as JSON User Load (0.4ms) SELECT "users".* FROM "users" WHERE (users.deleted = 0) ORDER BY users.id DESC Admin Load (0.3ms) SELECT "admins".* FROM "admins" WHERE "admins"."id" = 1 AND (admins.deleted = 0) ORDER BY admins.id DESC LIMIT 1 Completed 200 OK in 4ms (Views: 2.1ms | ActiveRecord: 0.6ms) [2013-05-05 22:05:01] WARN Could not determine content-length of response body. Set content-length of the response or set Response#chunked = true </code></pre> <p>However i am not able to display the data on the android screen/emulator.</p> <p>Please help me with this.</p>
 

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