it seams that `rememberSaveableStateHolder` is broken in som

Question

it seams that `rememberSaveableStateHolder` is broken in somehow in alpha12 Consider example from here <https github com androidx androidx blob androidx main compose runtime runtime saveable samples src main java androidx compose runtime saveable samples SaveableStateHolderSamples kt|https github com androidx androidx blob androidx main compose runtime runtime sa compose runtime saveable samples SaveableStateHolderSamples kt> and change ``` Box modifier restorableStateHolder SaveableStateProvider currentScreen content currentScreen ``` to ``` Box modifier restorableStateHolder SaveableStateProvider currentScreen Crossfade targetState = currentScreen content it ``` you will notice that animation doesn t work If you will remove that state holder ``` Box modifier Crossfade targetState = currentScreen content it ``` crossfade works So either `stateholder` is broken or `crossfade` From what I unsderstand problem is that Crossfade implementation uses `remember` to store items to render during transition What I wanted to achieve is some nice animation between screens What to do thinking face scream cat

Mikołaj Kąkol · Answer

< Adam Powell> could you take a look relaxed

Mikołaj Kąkol · Answer

and idea like ``` Crossfade targetState = currentScreen Box modifier restorableStateHolder SaveableStateProvider currentScreen content it ``` crashes after screen change with ``` java lang IllegalArgumentException Key screen2 was used multiple times at androidx compose runtime saveable SaveableStateHolderImpl$SaveableStateProvider$1 invoke SaveableStateHolder kt 91 ```

Andrey Kulikov · Answer

you need to first call Crossfade and only then SaveableStateProvider

Andrey Kulikov · Answer

there is a demo which does exactly this <https cs android com androidx platform frameworks support + androidx main compose animation animation integration tests animation demos src main java androidx compose animation demos CrossfadeDemo kt q=crossfadedemo amp ss=androidx|https cs android com androidx platform frameworks support + androidx main compose animation demos CrossfadeDemo kt q=crossfadedemo amp ss=androidx>

Andrey Kulikov · Answer

in your last sample you did it almost right but you are ignoring the parameter which Crossfade gives you in a trailing lambda please see how it is done in the demo I shared

Albert Chang · Answer

I think your problem here is that when `currentScreen` changes instead of recomposing the composable passed to `SaveableStateProvider` a new composition is created which means that the `Crossfade` is not the same to the old `Crossfade` thus not working

Mikołaj Kąkol · Answer

thank you Andrey that worked ``` Crossfade targetState = currentScreen Box modifier restorableStateHolder SaveableStateProvider it content it ``` amazing