Is anyone using coroutines succesfully in iOS? Im ...

# multiplatform

[carlos cdmp]

Is anyone using coroutines succesfully in iOS? Im looking for an actual implementation for the Main and IO Dispatcher

[russhwolf]

IO dispatcher is tough in the single-threaded coroutine world. For a Main dispatcher see https://github.com/JetBrains/kotlinconf-app/blob/master/common/src/iosMain/kotlin/org/jetbrains/kotlinconf/UI.kt for a Kotlin declaration or https://github.com/touchlab/DroidconKotlin/blob/ea62ee8a32b5966633c91cde64c6294f6a0f682d/iosApp/iosApp/UI.swift for a Swift one.

[Sergioedcigreja]

actual val ApplicationDispatcher: CoroutineDispatcher =
NsQueueDispatcher(dispatch_get_main_queue())

internal class NsQueueDispatcher(
private val dispatchQueue: dispatch_queue_t
) : CoroutineDispatcher() {
override fun dispatch(context: CoroutineContext, block: Runnable) {
dispatch_async(dispatchQueue) {
block.run()
}

}
}

[carlos cdmp]

Ok

[carlos cdmp]

my implementation was like that already

[carlos cdmp]

but looks like in android im able to come back to main thread to set the view label, but in ios it doesnt work

[carlos cdmp]

[carlos cdmp]

the code is in https://github.com/carlosdmp/recipe-multiplatform

[carlos cdmp]

if someone have any idea it would really help

[louiscad]

First result on Google for "kotlin ios main dispatcher" brings a GitHub issue, where the most positively reacted to comment is this one with a read to copy-paste solution for macOS and iOS: https://github.com/Kotlin/kotlinx.coroutines/issues/470#issuecomment-440080970

[louiscad]

It supports cancellation and delay, which are very important.

[kpgalligan]

I’m definitely no expert on coroutines in practice, but you probably don’t want to be using Global? https://github.com/carlosdmp/recipe-multiplatform/blob/master/app/src/commonMain/kotlin/presentation/RecipePresenter.kt

[kpgalligan]

In any case, just reading it, it looks like you’re passing data through closures from something in a background thread to the main thread, which is simply not going to work like that.

[kpgalligan]

You need to understand native threading and state rules first, and/or wait out the result of the multithreaded coroutines and “relaxed mode” https://github.com/Kotlin/kotlinx.coroutines/issues/462

[kpgalligan]

Some posts on native threading. Doesn’t go into coroutines, but hopefully helps with the basics: https://medium.com/@kpgalligan/kotlin-native-stranger-threads-ep-1-1ccccdfe0c99?source=your_stories_page--------------------------- https://medium.com/@kpgalligan/kotlin-native-stranger-threads-ep-2-208523d63c8f

[Arkadii Ivanov]

I would stick these articles somewhere in official docs so everyone could read them beforehand.

[kpgalligan]

So would I, but I am biased

[kpgalligan]

I should have them in my bookmarks at least. I need to look them up whenever I post them