Android Compose Typesafe navigation: Passing a List

Question

I want to pass a list of objects to another composable screen through Typse safe navigation but I get this error:

Route com.home.ui.OwnerGraph.FirstLogin.FirstLoginScreen2 could not find any NavType for argument list of type kotlin.collections.ArrayList - typeMap received was {}

The destination:

composable<OwnerGraph.FirstLogin.FirstLoginScreen2>(
            typeMap = mapOf(
                typeOf<ArrayList<PropertyTagNavigation>>() to CustomNavType.List,
            )

The navigation destination

    @Serializable
    data class FirstLoginScreen2(val list: ArrayList<PropertyTagNavigation>)

The object that being passed:

@Serializable
data class PropertyTagNavigation(
    val id: Int,
    val name: String,
)

NavType:

   val List = object : NavType<ArrayList<PropertyTagNavigation>>(
        isNullableAllowed = false
    ) {
        override fun get(bundle: Bundle, key: String): ArrayList<PropertyTagNavigation>? {
            return Json.decodeFromString(bundle.getString(key) ?: return null)
        }

        override fun parseValue(value: String): ArrayList<PropertyTagNavigation> {
            return Json.decodeFromString(Uri.decode(value))
        }

        override fun serializeAsValue(value: ArrayList<PropertyTagNavigation>): String {
            return Uri.encode(Json.encodeToString(value = value))
        }

        override fun put(bundle: Bundle, key: String, value: ArrayList<PropertyTagNavigation>) {
            bundle.putString(key, Json.encodeToString(value))
        }

    }

The destination:

@HiltViewModel
class FirstLoginOwnerSecondScreenViewModel @Inject constructor(
    savedStateHandle: SavedStateHandle,
) : ViewModel() {
    private val _state = MutableStateFlow(
        FirstLoginOwnerSecondScreenState(
            regionPropertyList = savedStateHandle
                .toRoute<OwnerGraph.FirstLogin.FirstLoginScreen2>().list.toPropertyTag()
        )
    )
....
}

And debugging it the savedStateHandle actually recieves the data but the error happens:

Inside the savedStateHandle :

list -> [{"id":1,"name":"xyz"},{"id":2,"name":"ffff"},.....]

Answer 1

You need pass typeMap parameter to savedStateHandle.toRoute() function