Child Stack with custom `ComponentContext`¶

Custom ComponentContext allows passing extra data and functionality to every child component. See Custom ComponentContext page for more information about creating custom AppComponentContext.

In order to pass custom component context like AppComponentContext to child stack components, make an extension function on your AppComponentContext interface. This custom extension function will initialize the Child Stack and provide every child an AppComponentContext.

fun <C : Parcelable, T : Any> AppComponentContext.appChildStack(
    source: StackNavigationSource<C>,
    initialStack: () -> List<C>,
    configurationClass: KClass<out C>,
    key: String = "DefaultStack",
    handleBackButton: Boolean = false,
    childFactory: (configuration: C, AppComponentContext) -> T
): Value<ChildStack<C, T>> =
    childStack(
        source = source,
        initialStack = initialStack,
        configurationClass = configurationClass,
        key = key,
        handleBackButton = handleBackButton
    ) { configuration, componentContext ->
        childFactory(
            configuration,
            DefaultAppComponentContext(
                componentContext = componentContext
            )
        )
    }

inline fun <reified C : Parcelable, T : Any> AppComponentContext.appChildStack(
    source: StackNavigationSource<C>,
    noinline initialStack: () -> List<C>,
    key: String = "DefaultStack",
    handleBackButton: Boolean = false,
    noinline childFactory: (configuration: C, AppComponentContext) -> T
): Value<ChildStack<C, T>> =
    appChildStack(
        source = source,
        initialStack = initialStack,
        configurationClass = C::class,
        key = key,
        handleBackButton = handleBackButton,
        childFactory = childFactory,
    )

Finally, in your components you can use the new extension function that will utilize the custom AppComponentContext.

interface RootComponent {

    val childStack: Value<ChildStack<*, Child>>

    sealed class Child {
        class ListChild(val component: ItemList) : Child()
        class DetailsChild(val component: ItemDetails) : Child()
    }
}

class DefaultRootComponent(
    componentContext: AppComponentContext
) : RootComponent, AppComponentContext by componentContext {

    private val navigation = StackNavigation<Config>()

    private val _childStack =
        childStack(
            source = navigation,
            initialConfiguration = Config.List,
            handleBackButton = true, // Pop the back stack on back button press
            childFactory = ::createChild,
        )

    override val childStack: Value<ChildStack<*, RootComponent.Child>> = _childStack

    private fun createChild(config: Config, componentContext: AppComponentContext): RootComponent.Child =
        TODO('Initialize child based on config with the custom component context')

    private fun itemList(componentContext: AppComponentContext): ItemListComponent =
        TODO('Initialize ItemDetails with the custom component context')

    private fun itemDetails(componentContext: AppComponentContext, config: Config.Details): ItemDetailsComponent =
        TODO('Initialize ItemDetails with the custom component context')

    private sealed class Config : Parcelable {
        @Parcelize
        object List : Config()

        @Parcelize
        data class Details(val itemId: Long) : Config()
    }
}

Child Stack with custom ComponentContext¶

Child Stack with custom `ComponentContext`¶