SceneStrategyScope
- Cmn
class SceneStrategyScope<T : Any>
Scope used to create a Scene from a list of NavEntrys.
This Scope should be provided to the SceneStrategy.calculateScene function to create Scenes.
Summary
Public constructors | |
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<T : Any> SceneStrategyScope(onBack: () -> Unit) | Cmn |
Public properties | ||
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() -> Unit | A callback that should be connected to any internal handling of system back done by the returned | Cmn |
Public constructors
Public properties
onBack
val onBack: () -> Unit
A callback that should be connected to any internal handling of system back done by the returned Scene.
For example, if your Scene uses a separate window that handles system back itself or if the UI present in your Scene allows users to go back via a custom gesture or affordance, this callback allows you to bubble up that event to the SceneState / androidx.navigation3.ui.NavDisplay that interfaces with the developer owned back stack.
import androidx.compose.runtime.Composable import androidx.compose.ui.window.Dialog import androidx.navigation3.runtime.NavEntry import androidx.navigation3.scene.OverlayScene import androidx.navigation3.scene.Scene import androidx.navigation3.scene.SceneStrategy import androidx.navigation3.scene.SceneStrategyScope /** Class that shows a [NavEntry] as a [Dialog]. */ class SimpleDialogScene<T : Any>( private val entry: NavEntry<T>, override val previousEntries: List<NavEntry<T>>, onBack: () -> Unit, ) : OverlayScene<T> { override val key = entry.contentKey override val entries = listOf(entry) override val overlaidEntries = previousEntries override val content: @Composable () -> Unit = { Dialog(onDismissRequest = onBack) { entry.Content() } } } /** * A [SceneStrategy] that shows every screen above the first one as a dialog. * * In a real example, you'd have developers opt into displaying their entry as a dialog by * providing a companion method that provides [NavEntry.metadata]. * * @see androidx.navigation3.scene.DialogSceneStrategy */ class SimpleDialogSceneStrategy<T : Any> : SceneStrategy<T> { override fun SceneStrategyScope<T>.calculateScene(entries: List<NavEntry<T>>): Scene<T>? { val entry = entries.lastOrNull() ?: return null val previousEntries = entries.dropLast(1) // Only show this as a dialog if there is something 'underneath' the dialog return if (previousEntries.isNotEmpty()) { SimpleDialogScene(entry, previousEntries, onBack) } else { null } } }