hello everyone, I have question regarding KMP stat...

# multiplatform

[Dmitry Danilau]

hello everyone,
I have question regarding KMP state and Swift UI.

Can you share your experience on how you manage state in SwiftUI from a shared StateHolder?
I have a StateHolder initialized in a native ViewModel (VM):

class MyVm: ObservableObject {
    @Published private(set) var state: ScreenState

    func observeViewState() async {
        for await kmpState in stateHolder.state {
            let viewState = onEnum(of: kmpState)
            // Update state here
        }
    }
}

data class ScreenState(
    val value1: SomeClass1,
    val value2: SomeClass2
)

My screen in SwiftUI uses properties to render different parts of the screen: value1 renders a list of items, and value2 renders a card.
As I understand it and what I see in the logs, if any property in the @Published property changes, it causes the entire screen to re-render (both components). That is, if value1 changes, I expect the list of items to re-render, and the card should remain untouched since there were no changes.
So far, I see that for each property in the state, I need to create its own @Published variable and pass it specifically to the component. This works on a simple screen, but if I have nested views and more than 3-5 such variables, to update a specific view in the hierarchy, I need to pass a specific @Published variable that will control the re-rendering when the corresponding variable changes.

What is the preferable approach?



Ty in advance

[Dmitry Danilau]

if someone will be interested in the response, you can find it here
https://kotlinlang.slack.com/archives/C9JM6Q2UX/p1720734713984049