Good morning (for some at least i guess 😅 ) I'm starting to use flows and I wonder how can i specify the thread the function I pass onto

collect

is executed. I'm trying:

launch(UI) {
  flow.collect {
    // i was hoping this was executed in UI
  }

should that be running in the UI Dispatcher?

You can use

kotlinx.coroutines.Dispatchers.Main

for the UI

You don’t need to launch { flow.collect { } }, because you would have callabacks and too many scopes Instead, you can launch flow in some scope, for example:

flow
    .onEach { doSmth(it) }
    .launchOn(Dispatcher.Main)

thanks 🙂

Yes it does,

launchOn()

calls

collect()

It consumes

ohhhhh! cool

Because other way we would have too many scopes

launch(UI) {
   flow.collect {
       too many scopes
   }
}

@julioyg When collecting a flow with

collect

, the passed block invoked for each collected item, and * always in the context of the current coroutine*. Note that

UI

is deprecated in favor of

Dispatchers.Main

. If you want some flow operations to be executed on another Thread/Dispatcher, you could use the

flowOn

operator. Note that unlike Rx `subscribeOn`/`observeOn`,

flowOn

is only applied to upstream operations.

thanks 🙂