Scene
OverlayScene |
A specific scene to render 1 or more |
A specific scene to render 1 or more NavEntrys.
A scene instance is identified by its key and the class of the Scene, and this change drives the top-level animation based on the SceneStrategy calculating what the current Scene is for the backstack.
The rendering for content should invoke the content for each NavEntry contained in entries at most once concurrently in a given Scene.
It is valid for two different instances of a Scene to render the same NavEntry. In this situation, the content for a NavEntry will only be rendered in the most recent target Scene that it is displayed in, as determined by entries.
Summary
Public properties |
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|---|---|---|
@Composable () -> Unit |
The content rendering the |
Cmn
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List<NavEntry<T>> |
The list of |
Cmn
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Any |
The key identifying the |
Cmn
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List<NavEntry<T>> |
The resulting |
Cmn
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Public properties
content
val content: @Composable () -> Unit
The content rendering the Scene itself.
This should call the content for the entries, and can add any arbitrary UI around them specific to the Scene.
entries
val entries: List<NavEntry<T>>
The list of NavEntrys that can be displayed in this scene.
When animating between scenes, the underlying content for each NavEntry will only be rendered by the scene that is most recently the target scene, and is displaying that NavEntry as determined by this entries list.
For example, consider a transition from Scene1 to Scene2 below:
Scene1: Scene2:
+---+---+ +---+---+
| | | | | |
| A | B | --> | B | C |
| | | | | |
+---+---+ +---+---+
Scene1.entries should be [A, B], and Scene2.entries should be [B, C]
When both are being rendered at the same time during the transition, the content for A will be rendered in Scene1, while the content for B and C will be rendered in Scene2.
key
val key: Any
The key identifying the Scene. This key will be combined with the class of the Scene to determine the key that drives the transition in the top-level animation for the NavDisplay.
Because the class of the Scene is also used, this key only needs to be unique for a given type of Scene to indicate a different instance of the Scene.
previousEntries
val previousEntries: List<NavEntry<T>>
The resulting NavEntrys that should be computed after pressing back updates the backstack.
This is required for calculating the proper predictive back state, which may result in a different scene being shown.
When predictive back is occurring, this list of entries will be passed through the SceneStrategy again, to determine what the resulting scene would be if the back happens.