Multi-module projects

A feature module can open a screen from another feature module without a dependency on that module. A screen is opened by NavigationKey, so the calling module depends on the module that declares the key and not on the module that declares the destination.

Module layout

Module Contains Depends on
navigation NavigationKeys enro-common
each feature destinations for some of the keys navigation, enro, the enro-processor KSP dependency
app the @NavigationComponent every feature

Feature modules do not depend on each other.

Keys

Declare each key that is used by more than one module in a separate navigation module. A key is a serializable class, so the navigation module requires only enro-common and the serialization plugin. The navigation module does not require Compose or the enro-processor.

/** Implemented in :recipes:modular:feature-home. */
@Serializable
data object HomeKey : NavigationKey

/** Implemented in :recipes:modular:feature-profile. */
@Serializable
data class ProfileKey(val userId: String) : NavigationKey

A key that is used by one feature only can be declared in that feature’s module.

Destinations

A feature module declares a destination with @NavigationDestination, as in a single-module project:

@Composable
@NavigationDestination(ProfileKey::class)
fun ProfileScreen() {
    val navigation = navigationHandle<ProfileKey>()
    Column(
        modifier = Modifier.fillMaxSize().padding(16.dp),
        verticalArrangement = Arrangement.spacedBy(8.dp),
    ) {
        Text("Profile: ${navigation.key.userId}", style = MaterialTheme.typography.titleLarge)
        Text("In :recipes:modular:feature-profile", style = MaterialTheme.typography.bodySmall)
        Button(onClick = { navigation.close() }) { Text("Back") }
    }
}

Add the enro-processor KSP dependency to every module that declares a @NavigationDestination. The enro-processor generates a binding for each @NavigationDestination.

dependencies {
    val enroProcessor = "dev.enro:enro-processor:3.0.0"
    add("kspCommonMainMetadata", enroProcessor)
    add("kspAndroid", enroProcessor)
    // ... one line per target
}

Another feature opens the screen with navigation.open(ProfileKey("user-123")). The calling feature does not import ProfileScreen.

The app module

Declare the @NavigationComponent in the app module. The app module must depend on every feature module. The enro-processor finds each feature’s generated bindings on the classpath and registers the bindings with the @NavigationComponent. The app module does not list the bindings.

If a destination is missing at runtime, check that the destination’s module has the enro-processor KSP dependency and that the app module depends on the destination’s module.

See also

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