SocketIO Java client not connecting

Question

I am attempting to create a simple connection between a python SocketIO server on repl.it and an Android Java app. When I attempt to connect to the socket nothing is happening.

Client:

Socket socket;
        try {
            socket = IO.socket("https://444ab0e8-2ef4-4b65-b8f8-c1116f6bd6bd-00-2z34bd8dh1mjs.riker.replit.dev:5000/");
        } catch (URISyntaxException e) {
            throw new RuntimeException(e);
        }

        socket.on(Socket.EVENT_CONNECT, new Emitter.Listener() {
            @Override
            public void call(Object... args) {
                Toast.makeText(MainActivity.this, "Connected", Toast.LENGTH_SHORT).show();
            }
        });

Server:

import eventlet
import socketio

sio = socketio.Server()
app = socketio.WSGIApp(sio)
clients = []

@sio.event
def connect(sid):
  clients.append(sid)
  print('connect ', sid)

@sio.event
def disconnect(sid):
  clients.remove(sid)
  print('disconnect ', sid)

if __name__ == '__main__':
  eventlet.wsgi.server(eventlet.listen(('', 5000)), app)

When I add socket.connect() or socket.open() under the socket initialization, it connects very briefly but the app crashes immediately. When I leave it out, nothing happens. I've also tried connecting with a python client and it works fine. The problem seems to be solely with the Android app.

Answer 1

I have fixed the problem. The reason it was crashing on socket.connect() was because I was attempting to Toast within the thread handling the connection event which was crashing the app. I fixed this by simple replacing the Toast with a Log message

Socket socket;
        try {
            socket = IO.socket("https://444ab0e8-2ef4-4b65-b8f8-c1116f6bd6bd-00-2z34bd8dh1mjs.riker.replit.dev:5000/");
            socket.connect();
        } catch (Exception e) {
            Log.e("STATE", "e", e);
            throw new RuntimeException("dasoi");
        }

        socket.on("message", new Emitter.Listener() {
            @Override
            public void call(Object... args) {
                Log.d("STATE", "connected");
            }
        });