I'm trying to use `savedInstanceState` with `MutableState` ```val themeColor by savedInstanceState(u...

# compose

[Se7eN]

I'm trying to use savedInstanceState with MutableState

val themeColor by savedInstanceState(user) { mutableStateOf(Color.Blue) }

but I'm getting this error:
java.lang.IllegalArgumentException: Please use savedInstanceState() if you want to save a MutableState

What am I doing wrong here?

[gildor]

As I understand you need rememberSavedInstanceState for mutable state:
https://developer.android.com/reference/kotlin/androidx/compose/runtime/savedinstancestate/package-summary#rememberSavedInstanceState(kotlin.Any,%20androidx.compose.runtime.savedinstancestate.Saver,%20kotlin.String,%20kotlin.Function0)

[Se7eN]

If you work with immutable objects savedInstanceState can suit you more as it wraps the value into the MutableState.

[gildor]

So you need immutable object? If so why do you use mutableState? Just remove mutableStateOf

[Se7eN]

Oops

[Se7eN]

Let me see

[gildor]

See an example here
https://developer.android.com/jetpack/compose/interop#savedinstancestate

[Se7eN]

I want to save the Color object but it's not supported so I was wrapping it in a mutable state

[Se7eN]

And no it's not mutable I got confused

[Se7eN]

And this gives the same error:

var themeColor by rememberSavedInstanceState { mutableStateOf(Color.Black) }

[Se7eN]

I guess I'll have to add a saver to use savedInstanceState

[Zhelyazko Atanasov]

I would implement a Saver and convert the Color to/from Int

[Andrey Kulikov]

savedInstanceState is basically a shortcut for rememberSavedInstanceState { mutableStateOf(...) }. and yes, you need yo use rememberSavedInstanceState and provide a custom Saver for colors