SceneStateKt

Added in 1.0.0

public final class SceneStateKt

Summary

Public methods
static final @NonNull SceneState<@NonNull T>
@Composable
<T extends Object> rememberSceneState(
    @NonNull List<@NonNull NavEntry<@NonNull T>> entries,
    @NonNull SceneStrategy<@NonNull T> sceneStrategy,
    @NonNull List<@NonNull SceneDecoratorStrategy<@NonNull T>> sceneDecoratorStrategies,
    SharedTransitionScope sharedTransitionScope,
    @NonNull Function0<Unit> onBack
)

Returns a SceneState that is remembered across compositions based on the parameters.

Public methods

rememberSceneState

@Composable
public static final @NonNull SceneState<@NonNull T> <T extends Object> rememberSceneState(
    @NonNull List<@NonNull NavEntry<@NonNull T>> entries,
    @NonNull SceneStrategy<@NonNull T> sceneStrategy,
    @NonNull List<@NonNull SceneDecoratorStrategy<@NonNull T>> sceneDecoratorStrategies,
    SharedTransitionScope sharedTransitionScope,
    @NonNull Function0<Unit> onBack
)

Returns a SceneState that is remembered across compositions based on the parameters.

This calculates all of the scenes and provides them in a SceneState.

import androidx.compose.material3.Text
import androidx.compose.runtime.mutableStateListOf
import androidx.compose.runtime.saveable.rememberSaveable
import androidx.navigation3.runtime.NavEntry
import androidx.navigation3.runtime.rememberDecoratedNavEntries
import androidx.navigation3.scene.SceneInfo
import androidx.navigation3.scene.SinglePaneSceneStrategy
import androidx.navigation3.scene.rememberSceneState
import androidx.navigation3.ui.NavDisplay
import androidx.navigationevent.compose.NavigationBackHandler
import androidx.navigationevent.compose.rememberNavigationEventState

val backStack = rememberSaveable { mutableStateListOf("a", "b") }
val entries =
    rememberDecoratedNavEntries(backStack) { key -> NavEntry(key) { Text("Key = $key") } }
val sceneState =
    rememberSceneState(
        entries,
        SinglePaneSceneStrategy(),
        onBack = { backStack.removeLastOrNull() },
    )
val currentScene = sceneState.currentScene
val navigationEventState =
    rememberNavigationEventState(
        currentInfo = SceneInfo(currentScene),
        backInfo = sceneState.previousScenes.map { SceneInfo(it) },
    )
NavigationBackHandler(
    navigationEventState,
    isBackEnabled = currentScene.previousEntries.isNotEmpty(),
    onBackCompleted = {
        // Remove entries from the back stack until we've removed all popped entries
        repeat(entries.size - currentScene.previousEntries.size) {
            backStack.removeLastOrNull()
        }
    },
)
NavDisplay(sceneState, navigationEventState)
Parameters
@NonNull List<@NonNull NavEntry<@NonNull T>> entries

all of the entries that are associated with this state
@NonNull SceneStrategy<@NonNull T> sceneStrategy

the SceneStrategy to determine which scene to render a list of entries.
@NonNull List<@NonNull SceneDecoratorStrategy<@NonNull T>> sceneDecoratorStrategies

list of SceneDecoratorStrategy to add content to the scene.
SharedTransitionScope sharedTransitionScope

the SharedTransitionScope needed to wrap the scene decorator. If this parameter is added, this function will require the LocalNavAnimatedContentScope.
@NonNull Function0<Unit> onBack

a callback for handling system back press.