Add adapter for managing lifecycle of MotionValues during a transition (db566112) · Commits · e / os / android_frameworks_base

packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/content/state/TransitionState.kt

+16 −1

Original line number	Diff line number	Diff line
		@@ -22,6 +22,8 @@ import androidx.compose.material3.ExperimentalMaterial3ExpressiveApi
		import androidx.compose.runtime.Stable
		import androidx.compose.runtime.derivedStateOf
		import androidx.compose.runtime.getValue
		import androidx.compose.runtime.mutableStateOf
		import androidx.compose.runtime.setValue
		import com.android.compose.animation.scene.ContentKey
		import com.android.compose.animation.scene.MutableSceneTransitionLayoutState
		import com.android.compose.animation.scene.OverlayKey
		@@ -241,6 +243,15 @@ sealed interface TransitionState {
		/** Additional gesture context whenever the transition is driven by a user gesture. */
		abstract val gestureContext: GestureContext?

		/**
		* True when the transition reached the end and the progress won't be updated anymore.
		*
		* [isProgressStable] will be `true` before this [Transition] is completed while there are
		* still custom transition animations settling.
		*/
		var isProgressStable: Boolean by mutableStateOf(false)
		private set

		/** The CUJ covered by this transition. */
		@CujType
		val cuj: Int?
		@@ -372,7 +383,11 @@ sealed interface TransitionState {
		check(_coroutineScope == null) { "A Transition can be started only once." }
		coroutineScope {
		_coroutineScope = this
		try {
		run()
		} finally {
		isProgressStable = true
		}
		}
		}

packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/mechanics/TransitionScopedMechanicsAdapter.kt

0 → 100644

+135 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2025 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		package com.android.compose.animation.scene.mechanics

		import androidx.annotation.VisibleForTesting
		import androidx.compose.runtime.mutableFloatStateOf
		import com.android.compose.animation.scene.ContentKey
		import com.android.compose.animation.scene.ElementKey
		import com.android.compose.animation.scene.ElementStateScope
		import com.android.compose.animation.scene.content.state.TransitionState
		import com.android.compose.animation.scene.transformation.CustomPropertyTransformation
		import com.android.compose.animation.scene.transformation.PropertyTransformationScope
		import com.android.mechanics.MotionValue
		import com.android.mechanics.ProvidedGestureContext
		import com.android.mechanics.spec.InputDirection
		import com.android.mechanics.spec.MotionSpec
		import kotlinx.coroutines.CoroutineScope
		import kotlinx.coroutines.launch

		/**
		* Callback to create a [MotionSpec] on the first call to [CustomPropertyTransformation.transform]
		*/
		typealias SpecFactory =
		PropertyTransformationScope.(content: ContentKey, element: ElementKey) -> MotionSpec

		/** Callback to compute the [MotionValue] per frame */
		typealias MotionValueInput =
		PropertyTransformationScope.(progress: Float, content: ContentKey, element: ElementKey) -> Float

		/**
		* Adapter to create a [MotionValue] and `keepRunning()` it temporarily while a
		* [CustomPropertyTransformation] is in progress and until the animation settles.
		*
		* The [MotionValue]'s input is by default the transition progress.
		*/
		internal class TransitionScopedMechanicsAdapter(
		private val computeInput: MotionValueInput = { progress, _, _ -> progress },
		private val stableThreshold: Float = MotionValue.StableThresholdEffect,
		private val label: String? = null,
		private val createSpec: SpecFactory,
		) {

		private val input = mutableFloatStateOf(0f)
		private var motionValue: MotionValue? = null

		fun PropertyTransformationScope.update(
		content: ContentKey,
		element: ElementKey,
		transition: TransitionState.Transition,
		transitionScope: CoroutineScope,
		): Float {
		val progress = transition.progressTo(content)
		input.floatValue = computeInput(progress, content, element)
		var motionValue = motionValue

		if (motionValue == null) {
		motionValue =
		MotionValue(
		input::floatValue,
		transition.gestureContext
		?: ProvidedGestureContext(
		0f,
		appearDirection(content, element, transition),
		),
		createSpec(content, element),
		stableThreshold = stableThreshold,
		label = label,
		)
		this@TransitionScopedMechanicsAdapter.motionValue = motionValue

		transitionScope.launch {
		motionValue.keepRunningWhile { !transition.isProgressStable \|\| !isStable }
		}
		}

		return motionValue.output
		}

		companion object {
		/**
		* Computes the InputDirection for a triggered transition of an element appearing /
		* disappearing.
		*
		* Since [CustomPropertyTransformation] are only supported for non-shared elements, the
		* [TransitionScopedMechanicsAdapter] is only used in the context of an element appearing /
		* disappearing. This helper computes the direction to result in [InputDirection.Max] for an
		* appear transition, and [InputDirection.Min] for a disappear transition.
		*/
		@VisibleForTesting
		internal fun ElementStateScope.appearDirection(
		content: ContentKey,
		element: ElementKey,
		transition: TransitionState.Transition,
		): InputDirection {
		check(!transition.isInitiatedByUserInput)

		val inMaxDirection =
		when (transition) {
		is TransitionState.Transition.ChangeScene -> {
		val transitionTowardsContent = content == transition.toContent
		val elementInContent = element.targetSize(content) != null
		val isReversed = transition.currentScene != transition.toScene
		(transitionTowardsContent xor elementInContent) xor !isReversed
		}

		is TransitionState.Transition.ShowOrHideOverlay -> {
		val transitioningTowardsOverlay = transition.overlay == transition.toContent
		val isReversed =
		transitioningTowardsOverlay xor transition.isEffectivelyShown
		transitioningTowardsOverlay xor isReversed
		}

		is TransitionState.Transition.ReplaceOverlay -> {
		transition.effectivelyShownOverlay == content
		}
		}

		return if (inMaxDirection) InputDirection.Max else InputDirection.Min
		}
		}
		}

packages/SystemUI/compose/scene/tests/goldens/motionValue_interruptedAnimation_completes.json

0 → 100644

+70 −0

Original line number	Diff line number	Diff line
		{
		"frame_ids": [
		0,
		16,
		32,
		48,
		64,
		80,
		96,
		112,
		128,
		144,
		160,
		176,
		192,
		208,
		224,
		240,
		256,
		272,
		288,
		304,
		320,
		336,
		352,
		368,
		384,
		"after"
		],
		"features": [
		{
		"name": "Foo_yOffset",
		"type": "float",
		"data_points": [
		{
		"type": "not_found"
		},
		{
		"type": "not_found"
		},
		175,
		175,
		174.00105,
		149.84001,
		114.73702,
		0,
		0,
		0,
		0,
		10.212692,
		42.525528,
		77.174965,
		106.322296,
		128.37651,
		144.09671,
		154.88022,
		162.08202,
		166.79778,
		169.83923,
		171.77742,
		173.00056,
		173.76627,
		174.24236,
		{
		"type": "not_found"
		}
		]
		}
		]
		}
		No newline at end of file

packages/SystemUI/compose/scene/tests/goldens/motionValue_withAnimation_prolongsTransition.json

0 → 100644

+48 −0

Original line number	Diff line number	Diff line
		{
		"frame_ids": [
		0,
		16,
		32,
		48,
		64,
		80,
		96,
		112,
		128,
		144,
		160,
		176,
		192,
		208,
		224,
		240,
		256,
		"after"
		],
		"features": [
		{
		"name": "Foo_yOffset",
		"type": "float",
		"data_points": [
		175,
		175,
		175,
		175,
		156.26086,
		121.784874,
		88.35684,
		61.32686,
		41.302353,
		27.215454,
		17.638702,
		11.284393,
		7.144104,
		4.4841614,
		2.7943878,
		1.7307587,
		1.0663452,
		0
		]
		}
		]
		}
		No newline at end of file

packages/SystemUI/compose/scene/tests/goldens/motionValue_withoutAnimation_terminatesImmediately.json

0 → 100644

+26 −0

Original line number	Diff line number	Diff line
		{
		"frame_ids": [
		0,
		16,
		32,
		48,
		64,
		80,
		"after"
		],
		"features": [
		{
		"name": "Foo_yOffset",
		"type": "float",
		"data_points": [
		175,
		145.83333,
		116.666664,
		87.5,
		58.33333,
		29.166672,
		0
		]
		}
		]
		}
		No newline at end of file