Hey guys, I’m a bit lost here with the StandaloneCoroutine{Cancelled}. In Android I have an addRepea...

# coroutines

[AJ]

Hey guys, I’m a bit lost here with the StandaloneCoroutine{Cancelled}. In Android I have an addRepeatingJob call which consumes a Channel from a ViewModel. And in the ViewModel I am sending data to the Channel with :

getViewModelScope().launch {
    while (this.isActive) {
        val dateString = calendarInteractor.getDateString()
        dateStringFlow.value = dateString
        log.debug { "sending date string to channel on thread " + ThreadInfo.currentThread() }
        dateStringChannel.send(dateString)
        delay(100)
    }
}

And after going out of the app and returning I am always having a StandaloneCoroutine{Cancelled} for the sending to Channel part, how come? Why does it get cancelled? The launch block is called once and then stops.
Any clues would be appreciated

[dshevliakov]

Where does addRepeatingJob come from? Is it lifecycle-ktx method?

[AJ]

Yes. The same behavior is encountered if launch a coroutines with

lifecycleScope.launch

in OnResume and then cancel it on OnPause, the coroutine is not launched again OnResume

[AJ]

Seems once the job is cancelled, even if I try to launch a new coroutine it is still cancelled

[AJ]

and the same behaviour if I even create a new CoroutineScope every time

CoroutineScope(Dispatchers.Main).launch

or with a job

CoroutineScope(Dispatchers.Main + SupervisorJob())

[dshevliakov]

Sorry, it is not clear to me. You expecting that old job will resume?

[dshevliakov]

When you launch new coroutine, I believe, new job is created

[dshevliakov]

Or second time you call launch never starts a new coroutine at all?

[AJ]

the second call to launch does not start the coroutine

[AJ]

it does not consume the Channel

[AJ]

override fun onResume() {
    super.onResume()
    calendarViewModel.startSendingDateChanges()
    listenToDateSubscription = lifecycleScope.launch {
        calendarViewModel.dateStringChannel.consumeEach {
            textView.text = it
        }
    }
}

this is my OnResume function, which calls the channel populating method and tries to consume it

[AJ]

the data is sent once to the channel and that’s it, nothing is consumed

[AJ]

the first app launch it works and if I go to an another app and back, it stops working

[AJ]

override fun onPause() {

super.onPause()

listenToDateSubscription?.cancel(“Activity paused”)

}

this is my onPause call, which just cancels the Job, basically I am doing by hand what was done by addRepeatingJob

[AJ]

changed to BroadcastChannel and it started working normally, but since BroadcastChannel is deprecated, refactored the whole solution to a StateFlow

[dshevliakov]

Nice. So it was because of channel. It seems your channel completes when there are no more consumers.