stateKeeper state updating from Ui

[lamtech58]

As the following codes, how can observe changes and update like the phoneNumber for exemple from my SignUpUi composable ?

class SignUpComponent(
    componentContext: ComponentContext
):SignUp, ComponentContext by componentContext {
    private val stateEntity = instanceKeeper.getOrCreate {
        StateEntity(
            savedState = stateKeeper.consume(
                "save_state_value", SerializableContainer.serializer())
        )
    }


    init {
        stateKeeper.register(
            key = "save_state_value",
            strategy = SerializableContainer.serializer(),
            supplier = stateEntity::saveState
        )
    }


}


interface SignUp {

}

class StateEntity(
    savedState: SerializableContainer?
): InstanceKeeper.Instance {

    var state: State = savedState?.consume(strategy = State.serializer()) ?: State()
        private set

    fun saveState() : SerializableContainer = SerializableContainer(
        value = state, strategy = State.serializer()
    )

    override fun onDestroy() {}

    @Serializable
    data class State(
        val phoneNumber: Long? = null,
    )
}

@Composable
fun SignUpUi(
    component: SignUp
){
    // ui codes...
}

[arkivanov]

You can use coroutines or Reaktive for observable things.

E.g. with coroutines this could like like this:

class StateEntity(
    savedState: SerializableContainer?
): InstanceKeeper.Instance {

    private val _state = MutableStateFlow(savedState?.consume(strategy = State.serializer()) ?: State())
    val state: StateFlow<State> = _state

    fun saveState() : SerializableContainer = SerializableContainer(
        value = _state.value, strategy = State.serializer()
    )

    private fun foo() {
        _state.update { it.copy(phoneNumber = ...) } 
    }

    override fun onDestroy() {}

    @Serializable
    data class State(
        val phoneNumber: Long? = null,
    )
}

[lamtech58]

imalready using this approach with my others components without stateKeeping, as im new in android this stateKeeper confussed me.

that way i dont need the interface SignUp {}to declare state ? cause im using that interface here

@Composable
fun SignUpUi(
    component: SignUp
){
    // ui codes...
}

[lamtech58]

And please whats the difference betwen StateFlow and Value from decompose ? and which one is preferable to use ?

[arkivanov]

Interfaces for components are optional. They can be useful if you want to create Compose/SwiftUI previews by writing a fake implementation of your component with fake data. Or if you want to write test doubles for navigation tests.

whats the difference betwen StateFlow and Value from decompose

Please see #69.