Hi. I'm using compose and compose-navigation with hilt injecting my viewModel, but I got `RuntimeExc...

# compose

[Tlaster]

Hi. I'm using compose and compose-navigation with hilt injecting my viewModel, but I got RuntimeException: Cannot create an instance of class MyViewModel . Does anyone have the same issue?

[jannis]

I’m using the same with the latest versions and I don’t get any errors. Does your ViewModel have a public constructor? Did you annotate your Activity/Fragment with @AndroidEntryPoint?

[jannis]

Or does your ViewModel have parameters and you don’t use a Factory?

[Tlaster]

Thanks, it works fine when not using NavHost from the new navigation-compose package.

[jannis]

Where exactly do you want to use it and how did you add it?

[jannis]

Works fine for me within a NavHost

[Tlaster]

I here is my activity's onCreate

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContent {
        val navController = rememberNavController()
        NavHost(
            navController = navController,
            startDestination = "home",
            builder = {
                composable("home") {
                    HomeScene()
                }
            }
        )
    }
}

and HomeScene is

@Composable
fun HomeScene() {
    val viewModel = viewModel<HomeViewModel>()
    Scaffold {
        Column(
            modifier = Modifier.fillMaxWidth().fillMaxHeight(),
            verticalArrangement = Arrangement.Center,
            horizontalAlignment = Alignment.CenterHorizontally
        ) {
            Image(vectorResource(id = R.drawable.ic_launcher_foreground))
        }
    }
}

and HomeViewModel is

class HomeViewModel @ViewModelInject constructor(
    private val repository: MyRepository
) : ViewModel() {
    fun myAccount() = repository.myAccount()
}

[jannis]

Ah. I’m injecting my viewModel manually atm (not using @ViewModelInject) 😞

[Tlaster]

Thanks! I'll try injecting manually since @ViewModelInject not working atm.

[allan.conda]

good to know, I might encounter same issue later

[allan.conda]

could you file a bug report? That would be helpful

[Ian Lake]

The Hilt docs explain what you need to do when using Navigation+Hilt ViewModels: https://developer.android.com/training/dependency-injection/hilt-jetpack#viewmodel-navigation

[Ian Lake]

That would apply to any viewModel() calls within a NavHost

[Tlaster]

Thanks! Now it works by passing defaultViewModelProviderFactory to viewModel()