hey guys, i'm confusing about whether it is appropriate to provide `NavController` in the form of `C...

# compose

[Young Rock]

hey guys, i'm confusing about whether it is appropriate to provide NavController in the form of CompositionLocal?

[yschimke]

I tried this and got advised to move away from it. I ended up with a top level App composable, that sets up navigation routes, but also creates lambdas to pass into each individual screen. It's really easy to overuse CompositionLocal but ultimately I felt it made the code cleaner, as I could leave the navigation logic in one place.

[Young Rock]

Thanks for your experience sharing, the problem I'm facing is that at the top composable screen, I need to write a lot of navigation events params like onClickXxx which are flowed up by child composable, that make the top screen's code full of navigation logic.

[yschimke]

You could funnel them through a single navigation lambda taking a destination. But wait for advice for others. I only have a few per screen

[nlindberg]

I ususally configure the viewmodel of the composable that sets up the navigation graph with the controller and then pass the viewmodel or an interface to it that does navigation. Not sure if there are any downsides to it 🤷

E.g.

val contentController = rememberAnimatedNavController()

mainViewModel.configure(contentController)
val starRoute = mainViewModel.startRoute()

Then in the childs e.g:

navigationActions.navigate(ContentScreen.DetailsScreen(it.id))

where NavigationActions is an interface on mainviewmodel.

override fun navigate(screen: ContentScreen) {
    viewModelScope.launch {
        val current = contentController?.currentDestination?.route
        if (current != screen.route) contentController?.navigate(screen.route)
    }
}

[yschimke]

I thought viewmodels shouldn't hold any references to activity or navigation controller. To avoid leaks?

[nlindberg]

Yeah could be, but the code looks cleaner, still have it on my todo to check if it leaks :d

[nlindberg]

Dont have any leaks according to LeakCanary 🤷