How to listen for multiple MUC chat group message at a single place outside chat window using Smack client in Android

Question

When I open a chat window of the particular group then, I create/join a group by below code

 private MultiUserChat joinRoom(String roomName) throws XmppStringprepException, XMPPException.XMPPErrorException, MultiUserChatException.NotAMucServiceException, SmackException.NotConnectedException, InterruptedException, SmackException.NoResponseException, MultiUserChatException.MucAlreadyJoinedException {
        if (roomName.equals("")) {
            logAndToast("Enter room name");
            return null;
        }

        if (MyXMPP.connection != null && MyXMPP.connection.isAuthenticated()) {
            // Get the MultiUserChatManager
            MultiUserChatManager manager = MultiUserChatManager.getInstanceFor(MyXMPP.connection);

            // Create the XMPP address (JID) of the MUC.
            EntityBareJid mucJid = (EntityBareJid) JidCreate.bareFrom(XMPPHelper.getRoomName(roomName));

            // Create a MultiUserChat using an XMPPConnection for a room
            MultiUserChat muc2 = manager.getMultiUserChat(mucJid);

            // User2 joins the new room
            // The room service will decide the amount of history to send
            // Create the nickname.
            Resourcepart nickname = Resourcepart.from(PreferenceManager.getStringPreference(this, PreferenceManager.XMPP_USER_NAME));

            MucEnterConfiguration.Builder mec = muc2.getEnterConfigurationBuilder(nickname);
           
            MucEnterConfiguration mucEnterConfig = mec.build();
            muc2.join(mucEnterConfig);
            return muc2;
        }
        return null;
}//end of MultiUserChat()

After that, I set incoming message listener for the group as below

multiUserChat = joinRoom("myRoomName"));
if (multiUserChat != null) {
    multiUserChat.addMessageListener(new MessageListener() {
        @Override
        public void processMessage(final Message message) {
            //here I received messages for the perticular group that I joined
        }
    });

    if (multiUserChat.isJoined()) {
        logAndToast("join xmpp room successfully");
    } else {
        logAndToast("join xmpp room not joined");
    }
}

I received all the messages by the above code when I am in a particular group window.

I need a solution for how to receive all the incoming messages in all the groups when I outside the group window.

I referred below links for MUC group chat https://download.igniterealtime.org/smack/docs/latest/documentation/extensions/muc.html

I searched/visited many links but could not found any solution that is useful for me. Please help me to provide a solution.

Thanks in Advance.

Answer 1

To get any group message without join or out side the chat window you need to subscribe that group.

We can achieve the same functionality using MucSub: Multi-User Chat Subscriptions https://docs.ejabberd.im/developer/xmpp-clients-bots/extensions/muc-sub/

We can subscribe group using below code for custom message

fun subscribeMUCRoom(context: Context?, toGroupName: String) { 
        if (!isStrNotNull(toGroupName) || MyXMPP.Companion.connection == null) {
            return
        }
        try {
            val iq: IQ = object : IQ("subscribe", "urn:xmpp:mucsub:0") {
                override fun getIQChildElementBuilder(xml: IQChildElementXmlStringBuilder): IQChildElementXmlStringBuilder {
                    xml.append(" nick=")
                    xml.append("'" + Your Display Name + "'")
                    xml.rightAngleBracket()
                    xml.append("""<event node='urn:xmpp:mucsub:nodes:messages' />
    <event node='urn:xmpp:mucsub:nodes:affiliations' />
    <event node='urn:xmpp:mucsub:nodes:subject' />
    <event node='urn:xmpp:mucsub:nodes:config' />""")
                    return xml
                }
            }
            iq.type = IQ.Type.set
            iq.setTo(toGroupName+ "@conference.yourdomain.com)
            iq.setFrom(userJid)
            setIQ(iq)
            connection?.sendStanza(iq)
            Log.d(TAG, "subscribeMUCRoom :: " + iq.toString() + " :: " + iq.childElementXML)
        } catch (e: Exception) {
            e.printStackTrace()
        }
    }

You can listen your success failure of custom message by this code

@Throws(NotConnectedException::class, InterruptedException::class)
    fun setIQ(iq: IQ?) {
        MyXMPP.connection!!.sendIqWithResponseCallback(iq, PacketListener { packet -> d(TAG, "setIQ :: success : $packet" /*.toXML()*/) }, ExceptionCallback { exception ->
            exception.printStackTrace()
            d(TAG, "setIQ :: processException : " + exception.message)
        }, 10000)
    }

Once you have successfully subscribed that group you can listen incoming message for that subscribed group using below code

private fun groupMessageListener() {
        connection!!.addAsyncStanzaListener(StanzaListener { packet ->
            val message = packet as Message
            
        }, AndFilter(StanzaTypeFilter.MESSAGE, MessageTypeFilter.GROUPCHAT))
    }