Hi all, Did anyone try using SnapShotStateMap to r...

# compose-android

[Ajay Chandran]

Hi all,
Did anyone try using SnapShotStateMap to render items in LazyColumn? SnapShotStateMap implements MutableMap and hence it doesn't follow order. Does anyone know any workaround to make the SnapShotStateMap into an ordered map?

[Stylianos Gakis]

What does it being a MutableMap have to do with how it's ordered?

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

Guaranteed insertion order is a property of LinkedHashMap which is what I believe MutableMap uses on jvm. SnapshotStateMap uses kotlinx.immutable persistent map, which I guess doesn’t have that property?

[Ajay Chandran]

Yes, SnapshotStateMap uses MutableMap implementation and doesn't follow any order and hence I couldn't able to use the map inside the lazycolumn items.

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

You could store IDs in a list for ordering. it’s 2 data structures instead of one, and twice the state reads, but pretty simple to implement

[Atul Gupta]

BTW you can also use SnapshotStateList if using SnapShotStateMap is not required

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

Yea, store ids in a SnapshotStateList

[Ajay Chandran]

Well if i store Ids in a snapshotstatelist, it can't be used for smart recomposition since the Ids won't be changed and hence there isn't any need to have a SnapShotStateList. If i pass the Ids to the LazyColumn, how will it possibly know that a particular item is changed and has to be recomposed?

[Atul Gupta]

Store Pair(id, item) in the list.. here issue is that not all types of collection is provided by the Snapshot
Alternatively you can use two different things.. one for ordering(SnapShotStateList) and one for values SanpShotStateMap and then you can observer both

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

Store the ids in a list, then each item in your lazy column looks up the rest of the data for that item (eg from a SnapshotStateMap)