I noticed in the release notes the dependency is l...

# compose

[FlowFan]

I noticed in the release notes the dependency is listed as org.jetbrains.androidx.navigation:navigation3-*:1.0.0-alpha04, but I had to change it to org.jetbrains.androidx.navigation3:navigation3-* to resolve a "Could not find" error. Is this a typo in the documentation?

[FlowFan]

I'm now encountering: "Could not find org.jetbrains.androidx.navigation3navigation3 runtime1.0.0-alpha04." Only the navigation3-ui module appears to be available. Am I doing something wrong here?

[Konstantin Tskhovrebov]

There is no org.jetbrains.androidx.navigation3:navigation3-runtime library
Only androidx.navigation3:navigation3-runtime

[Konstantin Tskhovrebov]

https://developer.android.com/kotlin/multiplatform#kotlin-multiplatform-and-jetpack-libraries

[FlowFan]

kotlinx.serialization.SerializationException: Serializer for subclass 'Home' is not found in the polymorphic scope of 'NavKey'.
Check if class with serial name 'Home' exists and serializer is registered in a corresponding SerializersModule.
To be registered automatically, class 'Home' has to be '@Serializable', and the base class 'NavKey' has to be sealed and '@Serializable'.
	at kotlinx.serialization.internal.AbstractPolymorphicSerializerKt.throwSubtypeNotRegistered(AbstractPolymorphicSerializer.kt:102)

I'm currently encountering this runtime error. Am I missing some dependency? Here are my code and dependencies:

androidx-navigation3-runtime = { group = "androidx.navigation3", name = "navigation3-runtime", version = "1.0.0-beta01" }
androidx-navigation3-ui = { group = "org.jetbrains.androidx.navigation3", name = "navigation3-ui", version = "1.0.0-alpha04" }
kotlinx-serialization-core = { group = "org.jetbrains.kotlinx", name = "kotlinx-serialization-core", version = "1.9.0" }
kotlinSerialization = { id = "org.jetbrains.kotlin.plugin.serialization", version = "2.2.20" }

@Serializable
sealed class Screen : NavKey
@Serializable
open class Home(val id: String) : Screen()
@Serializable
open class Details(val itemId: Long) : Screen()
val config = SavedStateConfiguration {
    serializersModule = SerializersModule {
        polymorphic(baseClass = Screen::class) {
            subclass(serializer = Home.serializer())
            subclass(serializer = Details.serializer())
        }
    }
}
NavDisplay(
    backStack = rememberNavBackStack(config, Home("1")),
    entryProvider = entryProvider {
        entry<Home> {
        }
        entry<Details> {
        }
    }
)

[Konstantin Tskhovrebov]

check my repo: https://github.com/terrakok/nav3-recipes

[FlowFan]

When I changed polymorphic(baseClass = Screen::class) to polymorphic(baseClass = NavKey::class), it ran successfully. What's confusing is that the sample code in androidx.navigation3.runtime.samples is written exactly like that.

@Composable
@Sampled
fun rememberNavBackStack_withSerializersModule() {
    val config = SavedStateConfiguration {
        // Register subtypes for open polymorphism or multiplatform use.
        serializersModule = SerializersModule {
            polymorphic(baseClass = Screen::class) {
                subclass(serializer = Home.serializer())
                subclass(serializer = Details.serializer())
            }
        }
    }

    // Pass the configuration so encoding/decoding works consistently.
    rememberNavBackStack(config, Home("start"))
}

[Konstantin Tskhovrebov]

cc @Ian Lake
would be good to add it in the Nav3 doc

[Ian Lake]

Ah, yep. rememberNavBackStack is always going to use NavKey as its base since it returns a NavBackStack<NavKey>, so polymorphic(baseClass = NavKey::class) is expected.

If you dropped down a layer and used rememberSerializable(configuration) { NavBackStack<Screen>(Home("start")) } to get a NavBackStack<Screen>, then you could use polymorphic(baseClass = Screen::class) - that would have the added benefit of only allowing your Screen subtypes into your back stack

[Ian Lake]

Since otherwise your Screen type is quite useless and could simply be removed entirely

[Ian Lake]

We'll be fixing the sample in http://r.android.com/3838540 though