Merge "Allow ElementScenePicker to return `null` (1/2)" into main (5b24f016) · Commits · e / os / android_frameworks_base

packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/Element.kt

+5 −3

Original line number	Diff line number	Diff line
		@@ -300,14 +300,16 @@ internal fun shouldDrawOrComposeSharedElement(
		val fromScene = transition.fromScene
		val toScene = transition.toScene

		val chosenByPicker =
		val pickedScene =
		scenePicker.sceneDuringTransition(
		element = element,
		transition = transition,
		fromSceneZIndex = layoutImpl.scenes.getValue(fromScene).zIndex,
		toSceneZIndex = layoutImpl.scenes.getValue(toScene).zIndex,
		) == scene
		return chosenByPicker \|\| transition.currentOverscrollSpec?.scene == scene
		)
		?: return false

		return pickedScene == scene \|\| transition.currentOverscrollSpec?.scene == scene
		}

		private fun isSharedElementEnabled(

packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/TransitionDsl.kt

+24 −26

Original line number	Diff line number	Diff line
		@@ -205,7 +205,9 @@ interface OverscrollScope {
		interface ElementScenePicker {
		/**
		* Return the scene in which [element] should be drawn (when using `Modifier.element(key)`) or
		* composed (when using `MovableElement(key)`) during the given [transition].
		* composed (when using `MovableElement(key)`) during the given [transition]. If this element
		* should not be drawn or composed in neither [transition.fromScene] nor [transition.toScene],
		* return `null`.
		*
		* Important: For [MovableElements][SceneScope.MovableElement], this scene picker will always
		* be used during transitions to decide whether we should compose that element in a given scene
		@@ -217,12 +219,13 @@ interface ElementScenePicker {
		transition: TransitionState.Transition,
		fromSceneZIndex: Float,
		toSceneZIndex: Float,
		): SceneKey
		): SceneKey?

		/**
		* Return [transition.fromScene] if it is in [scenes] and [transition.toScene] is not, or return
		* [transition.toScene] if it is in [scenes] and [transition.fromScene] is not, otherwise throw
		* an exception (i.e. if neither or both of fromScene and toScene are in [scenes]).
		* [transition.toScene] if it is in [scenes] and [transition.fromScene] is not. If neither
		* [transition.fromScene] and [transition.toScene] are in [scenes], return `null`. If both
		* [transition.fromScene] and [transition.toScene] are in [scenes], throw an exception.
		*
		* This function can be useful when computing the scene in which a movable element should be
		* composed.
		@@ -231,31 +234,22 @@ interface ElementScenePicker {
		scenes: Set<SceneKey>,
		transition: TransitionState.Transition,
		element: ElementKey,
		): SceneKey {
		): SceneKey? {
		val fromScene = transition.fromScene
		val toScene = transition.toScene
		val fromSceneInScenes = scenes.contains(fromScene)
		val toSceneInScenes = scenes.contains(toScene)
		if (fromSceneInScenes && toSceneInScenes) {

		return when {
		fromSceneInScenes && toSceneInScenes -> {
		error(
		"Element $element can be in both $fromScene and $toScene. You should add a " +
		"special case for this transition before calling pickSingleSceneIn()."
		)
		}

		if (!fromSceneInScenes && !toSceneInScenes) {
		error(
		"Element $element can be neither in $fromScene and $toScene. This either means " +
		"that you should add one of them in the scenes set passed to " +
		"pickSingleSceneIn(), or there is an internal error and this element was " +
		"composed when it shouldn't be."
		)
		}

		return if (fromSceneInScenes) {
		fromScene
		} else {
		toScene
		fromSceneInScenes -> fromScene
		toSceneInScenes -> toScene
		else -> null
		}
		}
		}
		@@ -312,8 +306,12 @@ class MovableElementScenePicker(private val scenes: Set<SceneKey>) : ElementScen
		transition: TransitionState.Transition,
		fromSceneZIndex: Float,
		toSceneZIndex: Float,
		): SceneKey {
		return if (scenes.contains(transition.toScene)) transition.toScene else transition.fromScene
		): SceneKey? {
		return when {
		scenes.contains(transition.toScene) -> transition.toScene
		scenes.contains(transition.fromScene) -> transition.fromScene
		else -> null
		}
		}
		}

packages/SystemUI/compose/scene/tests/src/com/android/compose/animation/scene/MovableElementScenePickerTest.kt

+16 −2

Original line number	Diff line number	Diff line
		@@ -38,8 +38,8 @@ class MovableElementScenePickerTest {
		}

		@Test
		fun toSceneNotInScenes() {
		val picker = MovableElementScenePicker(scenes = emptySet())
		fun fromSceneInScenes() {
		val picker = MovableElementScenePicker(scenes = setOf(TestScenes.SceneA))
		assertThat(
		picker.sceneDuringTransition(
		TestElements.Foo,
		@@ -50,4 +50,18 @@ class MovableElementScenePickerTest {
		)
		.isEqualTo(TestScenes.SceneA)
		}

		@Test
		fun noneInScenes() {
		val picker = MovableElementScenePicker(scenes = emptySet())
		assertThat(
		picker.sceneDuringTransition(
		TestElements.Foo,
		transition(from = TestScenes.SceneA, to = TestScenes.SceneB),
		fromSceneZIndex = 0f,
		toSceneZIndex = 1f,
		)
		)
		.isEqualTo(null)
		}
		}