Hi! How do I check what the current destination (object/class) is with the new type-safe navigation ...

# compose-android

[dave08]

Hi! How do I check what the current destination (object/class) is with the new type-safe navigation in 2.8.0?

[Muaz KADAN]

if you define screens in a sealed class like I do
I use this method to check the current destination

val backStackEntry by navController.currentBackStackEntryAsState()
if(backStackEntry?.destination?.route == Screen.Home::class.qualifiedName){
    // do something
}

[dave08]

Thanks! So the route is the qualifiedName...

[Kari Kähkönen]

Similar option is something like:

val navBackStackEntry by navController.currentBackStackEntryAsState()
val currentDestination = navBackStackEntry?.destination

when {
    destination.hasRoute(FooRoute::class) -> TODO()
    destination.hasRoute(BarRoute::class) -> TODO()
    else -> TODO()
}

[Muaz KADAN]

if(backStackEntry?.toRoute<Screen>() == Screen.Home){
    // do something
}

I don't know if this works yet or not. Haven't tried it recently

[dave08]

Yeah, I was hoping they had something a bit better than relying on qualifiedName (that might change one of these days... and is undocumented)

[Kari Kähkönen]

Also if using qualified name it might be good to verify that a build with R8 minify enabled works, if that is in use in release build. At least I had some issues, but I don’t remember if I used qualified name or something else. With the destination._hasRoute_(FooRoute::class) approach I haven’t had any issues.

[dave08]

@Muaz KADAN I doubt that would work unless your Screen is @Serializable and there's a descriminator field in the nav component's Kotlinx serialization decoder...

[Muaz KADAN]

annotating screens with @Serializable as the official documentation says should be enough @dave08

[Muaz KADAN]

There are other solutions that I found on StackOverFlow but they use Kotlin Reflect

[Muaz KADAN]

Which doesn't work for me because my project is Multiplatform 😄

[dave08]

annotating screens with @Serializable as the official documentation says should be enough

You tried?

[Muaz KADAN]

Yes I use it to determine when to show or not to show appBar like this

val showAppBar: Boolean
    @Composable get() =
        BottomNavigationScreen.entries.any { bottomNavScreen ->
            currentDestination?.route == bottomNavScreen.screen::class.qualifiedName
        } || currentDestination?.route == Screen.Tasks::class.qualifiedName ||
            currentBackStack.value.any { it.destination.route == Screen.Profile::class.qualifiedName }

[Muaz KADAN]

🫠

[dave08]

No, I meant backStackEntry?.toRoute<Screen>() == Screen.Home...

[dave08]

I tried the qualifiedName, and that actually worked, thanks!

[dave08]

I'm just not too happy to be using something undocumented...

[Ian Lake]

You should only be using hasRoute, as explained in the docs: https://developer.android.com/develop/ui/compose/navigation#bottom-nav

[dave08]

Thanks! Wow, it's hidden inside those code snippets in the bottom nav docs... maybe this should also be more prominent @Ian Lake?

[Ian Lake]

Where else would you like to see it except in the section where knowing what destination you are is important?

[dave08]

On the main type-safe navigation page, it would be great to see it, it's not such a long thing to explain, and in my case, I wasn't looking to migrate all my navigation yet... so I wasn't methodically looking through ALL the docs. I really wouldn't have guessed it being in that bottom bar page.. especially since the new type-safe nav is mixed in to the older string based nav docs...

[Ian Lake]

Mmm, type safe docs should be everywhere now - where are you still seeing string based nav docs?

[dave08]

Yeah, maybe it was still on the old docs when I started, wasn't 2.8.0 released recently... but there's also the xml navs... one way or the other, only that page with type-safe was the one I concentrated on when migrating...