title: Parsed JSON Data not displaying on android
body: <p>I have a JSON string which is generated by a php file. The problem is that the JSON string is not appearing on the textview of android. can anyone explain why?</p>
  
  <pre><code>public class AllUsersActivity extends ListActivity {
  
  // Progress Dialog
  private ProgressDialog pDialog;
  
  // Creating JSON Parser object
  JSONParser jParser = new JSONParser();
  
  ArrayList&lt;HashMap&lt;String, String&gt;&gt; usersList;
  
  // url to get all users list
  private static String url_all_users = "http://10.0.2.2/android_connect/get_all_users.php";
  
  // JSON Node names
  private static final String TAG_SUCCESS = "success";
  private static final String TAG_USERS = "users";
  private static final String TAG_UID = "UserID";
  private static final String TAG_FIRSTNAME = "FirstName";
  
  // users JSONArray
  JSONArray users = null;
  
  @Override
  public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.all_users);
  
      // Hashmap for ListView
      usersList = new ArrayList&lt;HashMap&lt;String, String&gt;&gt;();
  
      // Loading users in Background Thread
      new LoadAllusers().execute();
  
      // Get listview
      ListView lv = getListView();
  
      // on seleting single product
      // launching Edit Product Screen
      lv.setOnItemClickListener(new OnItemClickListener() {
  
          public void onItemClick(AdapterView&lt;?&gt; parent, View view,
                  int position, long id) {
              // getting values from selected ListItem
              String uid = ((TextView) view.findViewById(R.id.uid)).getText()
                      .toString();
  
              // Starting new intent
              Intent in = new Intent(getApplicationContext(),
                      UserDetailsActivity.class);
              // sending uid to next activity
              in.putExtra(TAG_UID, uid);
  
              // starting new activity and expecting some response back
              startActivityForResult(in, 100);
          }
      });
  
  }
  
  
  /**
   * Background Async Task to Load all product by making HTTP Request
   * */
  class LoadAllusers extends AsyncTask&lt;String, String, String&gt; {
  
      /**
       * Before starting background thread Show Progress Dialog
       * */
      @Override
      protected void onPreExecute() {
          super.onPreExecute();
          pDialog = new ProgressDialog(AllUsersActivity.this);
          pDialog.setMessage("Loading users. Please wait...");
          pDialog.setIndeterminate(false);
          pDialog.setCancelable(false);
          pDialog.show();
      }
  
      /**
       * getting All users from url
       * */
      protected String doInBackground(String... args) {
          // Building Parameters
          List&lt;NameValuePair&gt; params = new ArrayList&lt;NameValuePair&gt;();
          // getting JSON string from URL
          JSONObject json = jParser.makeHttpRequest(url_all_users, "GET", params);
  
          // Check your log cat for JSON reponse
          Log.d("All users: ", json.toString());
  
          try {
              // Checking for SUCCESS TAG
              int success = json.getInt(TAG_SUCCESS);
  
              if (success == 1) {
                  // users found
                  // Getting Array of users
                  users = json.getJSONArray(TAG_USERS);
  
                  // looping through All users
                  for (int i = 0; i &lt; users.length(); i++) {
                      JSONObject c = users.getJSONObject(i);
  
                      // Storing each json item in variable
                      String id = c.getString(TAG_UID);
                      String name = c.getString(TAG_FIRSTNAME);
  
                      // creating new HashMap
                      HashMap&lt;String, String&gt; map = new HashMap&lt;String, String&gt;();
  
                      // adding each child node to HashMap key =&gt; value
                      map.put(TAG_UID, id);
                      map.put(TAG_FIRSTNAME, name);
  
                      // adding HashList to ArrayList
                      usersList.add(map);
                  }
              } 
          } catch (JSONException e) {
              e.printStackTrace();
          }
  
          return null;
      }
  
      /**
       * After completing background task Dismiss the progress dialog
       * **/
      protected void onPostExecute(String file_url) {
          // dismiss the dialog after getting all users
          pDialog.dismiss();
          // updating UI from Background Thread
          runOnUiThread(new Runnable() {
              public void run() {
                  /**
                   * Updating parsed JSON data into ListView
                   * */
                  ListAdapter adapter = new SimpleAdapter(
                          AllUsersActivity.this, usersList,
                          R.layout.list_item, new String[] { TAG_UID,
                                  TAG_FIRSTNAME},
                          new int[] { R.id.uid, R.id.name });
                  // updating listview
                  setListAdapter(adapter);
              }
          });
  
      }
  
  }
  }
  </code></pre>
  
  <p>this is the JSON string from the PHP file</p>
  
  <pre><code>{"Users":[{"0":[],"UserID":"1","FirstName":"lalawee","Email":"12345","Password":null},{"0":[],"UserID":"2","FirstName":"shadowblade721","Email":"12345","Password":null,"1":[]},{"0":[],"UserID":"3","FirstName":"dingdang","Email":"12345","Password":null,"1":[],"2":[]},{"0":[],"UserID":"4","FirstName":"solidsnake0328","Email":"12345","Password":null,"1":[],"2":[],"3":[]}],"success":1}
  </code></pre>