Hi, how to update composable when a list changes by

rember { mutableStateOf(mutableListOf<Int>())}

?

are you mutating the actual list? state does not update unless you re-assign the state itself. ie, this will work:

val state = remember { mutableStateOf(listOf<Int>()) }
state.value = state.value + 1

This creates a new list with the additional element appended to the end of it and reassigns the value in the state. This allows the observers (ie, the recomposer) to know that the value changed and things need recomposing. However, if you do this:

state.value.add(1)

You are simply changing the data inside the list, which no one is observing. There's no way for the recomposer to know that anything changed.

Thanks for your reply! So I must assign

state

a new list to notify the recomposer right?

correct

Okay thanks a lot

mutableStateList is a special type of object that implements the StateObject interface. That interface is a hook into having mutable objects like this be able to inform observers of their changes. I still personally perfer to use a raw, immutable list than to use this special implementation

Ok thanks for your suggestion

This is also good if you haven't read it https://dev.to/zachklipp/two-mutables-dont-make-a-right-2kgp