I m not sure if I m doing something wrong or there s somethi kotlinlang #arrow-contributors

// Android's fragment code
override fun onResume() {
    super.onResume()
    unsafe {
        runBlocking {
            fx {
                println("DEBUG onResume 0 $threadName")
                continueOn(NonBlocking)
                println("DEBUG onResume 1 $threadName")
                continueOn(Dispatchers.Default)
                println("DEBUG onResume 2 $threadName")
                continueOn(Dispatchers.Main)
                println("DEBUG onResume main $threadName")
            }
        }
    }
}

output is:

DEBUG onResume 0 main
DEBUG onResume 1 ForkJoinPool-1-worker-2
DEBUG onResume 2 DefaultDispatcher-worker-2

gildor

04/03/2019, 9:35 AM

Correct, because you use runBlocking

code inside of coroutine is dispatched on threads which you requested, but runBlockling blocks thread and wait child coroutine and suspend function

aballano

04/03/2019, 9:37 AM

how would be the appropriate way to run this on Android then?

gildor

04/03/2019, 9:37 AM

just use

launch

instead

aballano

04/03/2019, 9:38 AM

but would that work on top of Arrow?

gildor

04/03/2019, 9:41 AM

I don’t know

In general you should start some background coroutine on background thread

aballano

04/03/2019, 9:42 AM

the thing is that switching to other threads works as seen in the output, the problem is when trying to go back to the main thread

and the idea is to do it on top of arrow (reason why I ask here 🙂)

gildor

04/03/2019, 9:42 AM

your problem is runBlocking

not thread switching

runBlocking blocks thread exactly what you shouldn’t do on main thread

but if you use runBlocking, it means that you already have dependency on kotlinx.coroutines, isn’t it?

pakoito

04/03/2019, 9:44 AM

launch

here @gildor, we’re doing our own coroutines runtime 😉

🍾 1

gildor

04/03/2019, 9:44 AM

I see

how you may launch async background task in Arrow?

pakoito

04/03/2019, 9:44 AM

runNonBlocking

👍 1

gildor

04/03/2019, 9:44 AM

😀

pakoito

04/03/2019, 9:44 AM

same file, same interface. next function 😛

🤦 1

gildor

04/03/2019, 9:44 AM

pretty stright-forward name 👍

pakoito

04/03/2019, 9:44 AM

https://github.com/arrow-kt/arrow/blob/master/modules/effects/arrow-effects-data/src/main/kotlin/arrow/effects/typeclasses/UnsafeRun.kt#L9

gildor

04/03/2019, 9:45 AM

I see, yeah, make sense

simon.vergauwen

04/03/2019, 9:47 AM

Soon we'll add interop with kotlinx again. So you'll be able to run fx code with launch/async.

But you might lose the optimisation we have in our runners. Hard to 100% confirm that already.

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