CODEWITHSUNDEEP
javaandroidnode.jssocketssocket.io
Player1
Player1

Reputation: 180

Android client not receiving socket.io message from node.js server

I have connected an Android Client to a node.js server using socket.io and i am able to send messages to the server but not receive on the client. For the client side i do somthing like 

Log.i("MainActivity: ", "sending message");
    final JSONObject sdpObj = new JSONObject();

    try {
        sdpObj.put("id","presenter");
        sdpObj.put("sdpOffer",localSdpOffer.description);
    } catch (JSONException e) {
        e.printStackTrace();
    }

    LoginActivity.mSocket.emit("new message", sdpObj);

and on the server i receive the object like:

 io.sockets.on('connection',function(socket){

        socket.on('new message',function(message){
              // some logic
          socket.emit('created',object);

then on the client side:

     LoginActivity.mSocket.on("created", new Emitter.Listener() {

        @Override
        public void call(Object... args) {
            Log.i( TAG, "message back:received ");

            User user = new User();
            JSONObject obj = null;
            try {
                obj = new JSONObject((String) args[0]);
                //Log.i(TAG,"SdpAnswer: "+args[0].sdpAnswer+"id "+obj.sdpAnswer);

            Log.i(TAG, "Instance of"+args[0].toString());
        }
    });
}

But for some reason it never receives the message. Anyone have some ideas why that may be? Thank you!

Upvotes: 3

Views: 2671

Answers (2)

Player1
Player1

Reputation: 180

OK so i figured it out after some more searching. It seems that in order to maintain correctly the socket connection for different android activities I had to implement a singleton class where i have defined the socket connection.The problem was that i instantiated the socket connection in one activity and tried to use that connection on another and even if I could send messages on another activity I could not receive any unless I moved the socket to the activities where the messages where received. You can find a lot of examples on how to implement a singleton class so it's not to hard and it solved my problem. Have a nice day :)

Upvotes: 1

Reuben Pinto
Reuben Pinto

Reputation: 41

If you are using the socket.io library by nkzawa as per the docs you have to process the internals of the call method using a runonUIThread method.

import com.github.nkzawa.emitter.Emitter;

private Emitter.Listener onNewMessage = new Emitter.Listener() {
    @Override
    public void call(final Object.. args) {
        getActivity().runOnUiThread(new Runnable() {
            @Override
            public void run() {
                JSONObject data = (JSONObject) args[0];
                String username;
                String message;
                try {
                    username = data.getString("username");
                    message = data.getString("message");
                } catch (JSONException e) {
                    return;
                }

                // add the message to view
                addMessage(username, message);
            }
        });
    }
};

This is what onNewMessage looks like. A listener is an instance of Emitter.Listener and must be implemented the call method. You’ll notice that inside of call() is wrapped by Activity#runOnUiThread(), that is because the callback is always called on another thread from Android UI thread, thus we have to make sure that adding a message to view happens on the UI thread.

Refer to this link for more info: Native Socket.IO and Android

Upvotes: 2

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