Add snapToIdleIfClose in BaseSceneTransitionLayoutState (cff3bc53) · Commits · e / os / android_frameworks_base

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

+10 −18

Original line number	Diff line number	Diff line
		@@ -701,27 +701,19 @@ internal class SceneNestedScrollHandler(
		gestureHandler.shouldImmediatelyIntercept(startedPosition = null)
		if (!canInterceptSwipeTransition) return@PriorityNestedScrollConnection false

		val swipeTransition = gestureHandler.swipeTransition
		val progress = swipeTransition.progress
		val threshold = layoutImpl.transitionInterceptionThreshold
		fun isProgressCloseTo(value: Float) = (progress - value).absoluteValue <= threshold

		// The transition is always between 0 and 1. If it is close to either of these
		// intervals, we want to go directly to the TransitionState.Idle.
		// The progress value can go beyond this range in the case of overscroll.
		val shouldSnapToIdle = isProgressCloseTo(0f) \|\| isProgressCloseTo(1f)
		if (shouldSnapToIdle) {
		swipeTransition.cancelOffsetAnimation()
		layoutState.finishTransition(swipeTransition, swipeTransition.currentScene)
		val hasSnappedToIdle = layoutState.snapToIdleIfClose(threshold)
		if (hasSnappedToIdle) {
		// If the current swipe transition is closed to 0f or 1f, then we want to
		// interrupt the transition (snapping it to Idle) and scroll the list.
		return@PriorityNestedScrollConnection false
		}

		// Start only if we cannot consume this event
		val canStart = !shouldSnapToIdle
		if (canStart) {
		// If the current swipe transition is not closed to 0f or 1f, then we want the
		// scroll events to intercept the current transition to continue the scene
		// transition.
		isIntercepting = true
		}

		canStart
		true
		},
		canStartPostScroll = { offsetAvailable, offsetBeforeStart ->
		val behavior: NestedScrollBehavior =

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

+25 −0

Original line number	Diff line number	Diff line
		@@ -24,6 +24,7 @@ import androidx.compose.runtime.getValue
		import androidx.compose.runtime.mutableStateOf
		import androidx.compose.runtime.remember
		import androidx.compose.runtime.setValue
		import kotlin.math.absoluteValue
		import kotlinx.coroutines.CoroutineScope
		import kotlinx.coroutines.channels.Channel

		@@ -236,6 +237,30 @@ internal abstract class BaseSceneTransitionLayoutState(initialScene: SceneKey) :
		transitionState = TransitionState.Idle(idleScene)
		}
		}

		/**
		* Check if a transition is in progress. If the progress value is near 0 or 1, immediately snap
		* to the closest scene.
		*
		* @return true if snapped to the closest scene.
		*/
		internal fun snapToIdleIfClose(threshold: Float): Boolean {
		val transition = currentTransition ?: return false
		val progress = transition.progress
		fun isProgressCloseTo(value: Float) = (progress - value).absoluteValue <= threshold

		return when {
		isProgressCloseTo(0f) -> {
		finishTransition(transition, transition.fromScene)
		true
		}
		isProgressCloseTo(1f) -> {
		finishTransition(transition, transition.toScene)
		true
		}
		else -> false
		}
		}
		}

		/**

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

+38 −0

Original line number	Diff line number	Diff line
		@@ -158,4 +158,42 @@ class SceneTransitionLayoutStateTest {
		.isNotNull()
		assertThat(state.transformationSpec.transformations).hasSize(2)
		}

		@Test
		fun snapToIdleIfClose_snapToStart() = runMonotonicClockTest {
		val state = MutableSceneTransitionLayoutStateImpl(TestScenes.SceneA, SceneTransitions.Empty)
		state.startTransition(
		transition(from = TestScenes.SceneA, to = TestScenes.SceneB, progress = { 0.2f }),
		transitionKey = null
		)
		assertThat(state.isTransitioning()).isTrue()

		// Ignore the request if the progress is not close to 0 or 1, using the threshold.
		assertThat(state.snapToIdleIfClose(threshold = 0.1f)).isFalse()
		assertThat(state.isTransitioning()).isTrue()

		// Go to the initial scene if it is close to 0.
		assertThat(state.snapToIdleIfClose(threshold = 0.2f)).isTrue()
		assertThat(state.isTransitioning()).isFalse()
		assertThat(state.transitionState).isEqualTo(TransitionState.Idle(TestScenes.SceneA))
		}

		@Test
		fun snapToIdleIfClose_snapToEnd() = runMonotonicClockTest {
		val state = MutableSceneTransitionLayoutStateImpl(TestScenes.SceneA, SceneTransitions.Empty)
		state.startTransition(
		transition(from = TestScenes.SceneA, to = TestScenes.SceneB, progress = { 0.8f }),
		transitionKey = null
		)
		assertThat(state.isTransitioning()).isTrue()

		// Ignore the request if the progress is not close to 0 or 1, using the threshold.
		assertThat(state.snapToIdleIfClose(threshold = 0.1f)).isFalse()
		assertThat(state.isTransitioning()).isTrue()

		// Go to the final scene if it is close to 1.
		assertThat(state.snapToIdleIfClose(threshold = 0.2f)).isTrue()
		assertThat(state.isTransitioning()).isFalse()
		assertThat(state.transitionState).isEqualTo(TransitionState.Idle(TestScenes.SceneB))
		}
		}