how to pass custom args in hilt viewModel android

Question

Screen(AppScreens.InfoScreen.route) { navBackStackEntry ->
    val viewModel = hiltViewModel<ProfileDisplayScreenViewModel>()
    val uiState by viewModel.uiState.collectAsState()
    LaunchedEffect(Unit) {
      viewModel.setUpId(navBackStackEntry.getInt()!!)
    }
    ProfileDisplayScreen(uiState, viewModel.interActor)
}

i don't want to use LaunchedEffect and i want to pass args directly is this possible ? if yes then how ?

Answer 1

Yes, you can pass arguments directly to your ViewModel without using LaunchedEffect. Here’s how you can achieve this using Hilt's SavedStateHandle and the Navigation Component.

class ProfileDisplayScreenViewModel @ViewModelInject constructor(
      private val savedStateHandle: SavedStateHandle,
      // other dependencies
) : ViewModel() {
 val uiState = // Your state handling logic

    init {
        val id =
            savedStateHandle.get<Int>("id") ?: throw IllegalArgumentException("ID is required")
        setUpId(id)
    }

    fun setUpId(id: Int) {
         // Your logic to set up the ID
    }
}

When navigating to your screen, pass the argument like this:

navController.navigate("info_screen/$id")

Define the route in your NavHost to accept the argument.

NavHost(navController, startDestination = "start_screen") {
composable("info_screen/{id}")
) { navBackStackEntry ->
    val viewModel: ProfileDisplayScreenViewModel = hiltViewModel(navBackStackEntry)
    val uiState by viewModel.uiState.collectAsState()
    
    ProfileDisplayScreen(uiState, viewModel.interActor)
   }
}