title: AlertDialog in onPostExecute not showing
body: <p>I am trying to show a Dialog box on onPostExecute method of an AsyncTask</p>
  
  <pre><code>@Override
  protected void onPostExecute(HttpResponse response) {
  if (response == null) {
              Log.d(TAG, "onPostExecute, response == null");
              AlertDialog.Builder builder = new AlertDialog.Builder(ConfirmPhoneNoCode.this);
              builder.setMessage("Are you sure you want to exit?").setCancelable(false)
                      .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                          public void onClick(DialogInterface dialog, int id) {
                              ConfirmPhoneNoCode.this.finish();
                          }
                      }).setNegativeButton("No", new DialogInterface.OnClickListener() {
                          public void onClick(DialogInterface dialog, int id) {
                              dialog.cancel();
                          }
                      });
              AlertDialog alert = builder.create();
          } else {
              int responseCode = response.getStatusLine().getStatusCode();
              String message = response.getStatusLine().getReasonPhrase();
              Log.d(TAG, "Response Code: " + String.valueOf(responseCode));
              Log.d(TAG, "Message: " + message);
          }
      }
  </code></pre>
  
  <p>I am getting the log message</p>
  
  <pre><code>03-31 23:02:42.912: D/ConfirmPhoneCode(21966): onPostExecute, response == null
  </code></pre>
  
  <p>that means </p>
  
  <pre><code>if(response == null) is executed but AlertDialog box don't show-up.
  </code></pre>
  
  <p>I will appreciate if someone could help me with this.</p>
  
  <p>Thanks in Advance.</p>