如何接收消息而不使用createChat for android XMPP chat smack api

Question

嗨,我对实现chatManagerListener接口内部的逻辑感到困惑Service.以下是我的服务代码:

public class MyService3 extends Service {
ChatManager chatManager;
ChatManagerListener chatManagerListener;
AbstractXMPPConnection abstractXMPPConnection;
MyXmpp2 myXmpp2;

public MyService3() {
}


@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    Log.d("Myservice3:","Started");

    abstractXMPPConnection = myXmpp2.getConnection();
    abstractXMPPConnection.addConnectionListener(new ConnectionListener() {
        @Override
        public void connected(XMPPConnection connection) {
            Log.d("XMPPConnection:","connected");
        }

        @Override
        public void authenticated(XMPPConnection connection, boolean resumed) {
            Log.d("XMPPConnection:","authenticated");
            //Once authenticated start listening for messages






        }

        @Override
        public void connectionClosed() {
            Log.d("XMPPConnection:","connectionClosed");
        }

        @Override
        public void connectionClosedOnError(Exception e) {
            Log.d("XMPPConnection:","connectionClosedOnError");
        }

        @Override
        public void reconnectionSuccessful() {
            Log.d("XMPPConnection:","reconnectionSuccessful");

        }

        @Override
        public void reconnectingIn(int seconds) {
            Log.d("XMPPConnection:","reconnectingIn");

        }

        @Override
        public void reconnectionFailed(Exception e) {
            Log.d("XMPPConnection:","reconnectionFailed");

        }
    });



    Log.d("isOnline:", myXmpp2.getConnection().isConnected() + "");
    chatManager = ChatManager.getInstanceFor(abstractXMPPConnection);
    chatManager.addChatListener(chatManagerListener);
    chatManagerListener = new ChatManagerListener() {
        @Override
        public void chatCreated(Chat chat, boolean createdLocally) {

            chat.addMessageListener(new ChatMessageListener() {
                @Override
                public void processMessage(Chat chat, Message message) {

                    Log.d("Hello::","World");
                   //NOT WORKNIG
                    if(message.getBody()!=null)
                    {
                        Log.d("Message::",message.getBody());
                    }
                }
            });
        }
    };





    return super.onStartCommand(intent, flags, startId);
}



}

无论什么时候发送一个数据包,我都会得到以下异常.我不知道为什么它会产生

Exception in packet listener java.lang.NullPointerException: Attempt to invoke interface method 'void org.jivesoftware.smack.chat.ChatManagerListener.chatCreated(org.jivesoftware.smack.chat.Chat, boolean)' on a null object reference
                                                                                       at org.jivesoftware.smack.chat.ChatManager.createChat(ChatManager.java:255)
                                                                                       at org.jivesoftware.smack.chat.ChatManager.createChat(ChatManager.java:287)

简单来说,我想知道如何在服务中实现ChatMessage监听器.请善待