Timeout in a coroutine, Kotlin

Question

I am working in Kotlin to create a UDP socket between an Android client and a server. For receiving messages, I'm using a coroutine, and the code itself works correctly, checking for every incoming message.

My objective now is to set a timeout (or something similar) of 30 seconds to detect if the communication has been lost. If the timeout is reached, I do NOT want the loop to block; I want it to continue to receive any incoming messages. I just want to log or display an appropriate message in a toast.

    val myCoroutineScope = lifecycleScope


    if (myCoroutineJob == null || myCoroutineJob?.isCompleted == true) {
        // Connection to the server
        myCoroutineScope.launch {
            withContext(Dispatchers.IO) {
                client = Client()
            }

            // A listener function is created, it is used to handle the data as needed
            client?.dataReceivedListeners?.add { data ->

                try {
                    receivedText = decompress(data)

                    val jsonObject = JSONObject(receivedText.toString())

                    # RECEIVED MESSAGES HANDLING....

                    }


                } catch (e: JSONException) {
                    # ERROR HANDLING ........

                }

            }

        }
    }

Answer 1

You can use withTimeoutOrNull for that. Note that it is a suspend function. It can be used like that:

val value = withTimeoutOrNull(5000) {
    // ... long running operation
    "Hello"
}

value will be either "Hello" or null in case the timeout of 5000ms was exceeded.