Hi ! Looking at <https://developer.android.com/jetpack/compose/state>, it is written that we may nee...

# compose

[loloof64]

Hi ! Looking at https://developer.android.com/jetpack/compose/state, it is written that we may need to create custom object saver to pass custom data to rememberSaveable , but how should I build such object ? Let's say for data class Point(val x: Int, val y:Int) ? Because there is not any example in the documentation, and I did not understand this sentence (build a custom object saver ), what interface should the saver have ? What is the Android class/object responsible for such interface ? Should I create a Bundle myself ?

[loloof64]

Finally, gonna try this : https://stackoverflow.com/questions/66547601/jetpack-compose-remembersaveable-leads-to-crash-when-an-app-goes-to-background

[Jorkoh]

https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:compose/[…]ava/androidx/compose/runtime/saveable/samples/SaverSamples.kt

[loloof64]

Thank you @Jorkoh. I've also managed by using a simple String serialization

[loloof64]

Here what I've achieved

CustomStateSaver

[Jorkoh]

I think the mapSaver sample would work nicely for this case but doing it with a String also works 👍

[Albert Chang]

You should use rememberSaveable(stateSaver = saver) { mutableStateOf(state) } and remove the MutableState type from your saver.

[loloof64]

Thank you @Albert Chang. I've tried to remove mitableStateOf from the saver, but this time I get an error Type 'DndData' has no method 'getValue(Nothing?, KProperty<*>)' and thus it cannot serve as a delegate .

[Albert Chang]

You shouldn't remove the mutableStateOf() in rememberSaveable. If you didn't, check if you are using the correct overload of rememberSaveable.

[loloof64]

Thank you, in this attempt I get an error inferred data is MutableState<DndData> but type DndData expected .

Untitled

[Albert Chang]

You are using the wrong overload. You need to use the version with stateSaver parameter.

[loloof64]

Thank you, it worked. And I can use delegation with by again.