How can I restart canceled job?

[Bill-Park]

After cancel job, how can I restart?
This is my code. (kotlin)

send_udp_repeat = launch(CommonPool) {
            var nextPrintTime = System.currentTimeMillis()
            while (isActive) {
                val currentTime = System.currentTimeMillis()
                if (currentTime >= nextPrintTime) {
                    sendUDPrequest(UDP_SERVER_IP, UDP_SERVER_PORT, UDP_SERVER_MSG)
                    nextPrintTime = currentTime + 2000L
                }
            }
        }
commu_status.setOnClickListener {
            if (send_udp_repeat.isActive == true) {
                send_udp_repeat.cancel()
            }
        }
menu_button.setOnClickListener {
            // I want to restart send_udp_repeat here
        }

[elizarov]

If you are running it all from UI thread, then it is quite easy via a bit of abstraction. You should just introduce a function to restart your coroutine. Select the block of code that is to the right of send_udp_repeat and press (Ctrl/Cmd-Shfit-M) to introduce a function:

fun launchSendUpdRepeat() = launch(CommonPool) {
            var nextPrintTime = System.currentTimeMillis()
            while (isActive) {
                val currentTime = System.currentTimeMillis()
                if (currentTime >= nextPrintTime) {
                    sendUDPrequest(UDP_SERVER_IP, UDP_SERVER_PORT, UDP_SERVER_MSG)
                    nextPrintTime = currentTime + 2000L
                }
            }
        }

send_udp_repeat = launchSendUdpRepeat()

Then change send_udp_repeat to a nullable type and rewrite your click listeners (note that you don't have to check for isActive):

commu_status.setOnClickListener {
            send_udp_repeat?.cancel()
            send_udp_repeat = null
        }
menu_button.setOnClickListener {
            send_udp_repeat = launchSendUdpRepeat()
        }

[Bill-Park]

It works for me.
Thanks you.