Websocket connection wasn't closed after the app killed

My Websocket client (OkHttp) doesn't close the connection after the app closed. It opens a new connection every time I open the app which makes the app suffering from multiple messages received on the old and the new Websocket connections from the broadcasting server.

Is that a normal behavior for the android client, as for what I have experienced with web-client, the session was closed properly after the tab killed?

I have been looking up the problem across the internet but no luck so far. I want to make sure whether it happened because of my bad code logic or just the buggy Websocket's implementation from the library?

Here is how I start a new websocket session in the main Activity

var request: Request = Request.Builder()
            .url("ws://$serverIP:8080/example/sim/speed")
            .build()
        var webSocketListener: WebSocketListener = object : WebSocketListener() {

            override fun callback(msg: Message) {
                updateSpeed(msg.content)
            }

            override fun onClosing(webSocket: WebSocket?, code: Int, reason: String?) {
                super.onClosing(webSocket, code, reason)
            }
        }

        var webSocket = client!!.newWebSocket(request, webSocketListener)

After that updateSpeed() will update a text view on UIThread

The onClosed event was not triggered when the app closed but only when the close function called manually.

I'm sure that it opened a new socket every time because I can see new sessions created on the server with different ports.

What I want is to have the app closing its connection before it was closed.

Thank you

I also encountered this issue, that WebSocket was still opened after my app was killed.

To solve this issue I manually close socket and remove all idle connections:

fun clear() {
    webSocket?.close(1001, "Android: User exited the game.")
    webSocket = null
    subs.clear()
    subs.add(Completable.fromAction {
        client.connectionPool.evictAll()
    }.subscribeOn(Schedulers.io()).subscribe({}, {}))
}

And I basically call clear() inside activity/ies, that might be opened during app kill.

override fun onDestroy() {
    super.onDestroy()
    App.webSocketClient().clear()
}

Not an ideal solution, but works every time.