I recently made a very simple comic viewer app for XKCD using Jetpack compose. However, my composables are too big, with lots of complicated business logic in it, launching lots of coroutines etc. I am thinking of making a custom state object inside which I am going to move all the business logic, leaving only the UI parts to the composable functions. Is it ok to launch composables from within state classes?

The phrasing of, "launch composables from within state classes" confuses me a bit, but I occasionally write state objects with suspend methods that keep updates/ongoing behavior running, and then have a composable do something like

@Composable
fun Thing(state: ThingState) {
  LaunchedEffect(state) {
    state.keepUpdated()
  }
  // ...
}

My question was, to use your example, should I make

state.keepUpdated

a suspend function and launch the coroutine from the composable, or is it better to make

state.keepUpdated

a regular function and launch the coroutine inside the method.

What scope would you launch it in/where would you call the launcher method?

Still a newbie so haven't thought about the details through, but I am currently using a

CoroutineScope

via

rememberCoroutineScope

in my composables.

Definitely don't raw launch from a

@Composable

- it's one thing if it's in a click handler or something but composables are transactional and launching is a side effect that needs to be controlled to only escape composition if composition successfully commits

It was for a click handler

Yeah if you have to provide a scope to the state object things get a lot more complicated

Ok thanks for pointing me in the right direction.

I'm not entirely sure it's the right direction yet, but I hope it's been a helpful direction to think in and I'm curious to see what you arrive at 🙂