title: Invitation Listener not working smack 4.2
body: <p>I can create group chat room successfully XMPP(smack). I have added
          invitation listener, but never called.   Does anyone know how to do it?</p>
  
  <h2>Using:</h2>
  
  <ol>
  <li>XMPP</li>
  <li>Smack 4.2</li>
  <li>Openfire server</li>
  </ol>
  
  <h2>Send Invitation code:</h2>
  
  <pre><code> muc.invite(userId +"@" +XMPP.getInstance().HOST + "/Smack", "Meet me in this excellent room");
  </code></pre>
  
  <h2>Invitation listener code:</h2>
  
  <pre><code>         MultiUserChatManager manager = MultiUserChatManager.getInstanceFor(connection);
              manager.addInvitationListener(new InvitationListener() {
                  @Override
                  public void invitationReceived(XMPPConnection xmppConnection, MultiUserChat muc, String inviter, String reason, String password, Message message) {
                      try {
                          muc.join(nickname);
                      } catch (SmackException.NoResponseException e) {
                          e.printStackTrace();
                      } catch (XMPPException.XMPPErrorException e) {
                          e.printStackTrace();
                      } catch (SmackException.NotConnectedException e) {
                          e.printStackTrace();
                      }
                  }
              });
  </code></pre>