Trying to render a list of items, each with their own `State`, and would like to keep track of the f...

# compose

[Tash]

Trying to render a list of items, each with their own State, and would like to keep track of the first & last item’s State. For some reason having trouble wrapping my mind around this particular scenario 🧵 ⬇️

[Tash]

I’m sure there’s a simple solution to this, but my mind is rejecting Compose-style thinking today 🙈 . Probably need more ☕ . Here’s some pseudocode of what I’m trying to achieve:

items.forEachIndexed { index, item ->
   val itemState = rememberItemState(key = item.id, /** etc **/)
   
   // Somehow do this
   if (index == items.size - 1) {
      lastItemState.value = itemState
   } else if (index == 0) {
      firstItemState.value = itemState
   }

   key(item.id) { Item(state = itemState, content = content) }
}

Any insight is much appreciated 🙏🏼

[Zach Klippenstein (he/him) [MOD]]

Any reason you’re not using a lazy list?

[Tash]

Trying to create these inside of a Box to achieve a stack

[Zach Klippenstein (he/him) [MOD]]

ah

[Zach Klippenstein (he/him) [MOD]]

you probably want to put all that inside the key block, that’s what will ensure that an item’s memoized state will move along with the item if the order of the list changes

[Tash]

Ahh, thats a good point, thank you

[Tash]

I was trying to understand if the if/else in there needs to happen in some type of Effect block or not 🤔

[Zach Klippenstein (he/him) [MOD]]

then I think that that if/else should just work

[Tash]

Oh I see

[Zach Klippenstein (he/him) [MOD]]

I don’t think it needs to be in an effect, assuming `firstItemState`/`lastItemState` are `MutableState`s – because they participate in the snapshot system, if the composition fails, those writes will be rolled back, so they don’t need to be done in an effect.

[Zach Klippenstein (he/him) [MOD]]

If they weren’t `MutableState`s, then i think they’d need to be in an effect

[Tash]

Ah yes of course. They are indeed MutableState s, so that should work. I’ll try moving everything into the key block and keep an eye on state integrity. Thank you loads!