MultiPointerDraggable velocityTracker should keep track of all events (ff114b1b) · Commits · e / os / android_frameworks_base

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

+53 −15

Original line number	Diff line number	Diff line
		@@ -221,21 +221,61 @@ internal class MultiPointerDraggableNode(
		private suspend fun PointerInputScope.pointerTracker() {
		val currentContext = currentCoroutineContext()
		awaitPointerEventScope {
		var velocityPointerId: PointerId? = null
		// Intercepts pointer inputs and exposes [PointersInfo], via
		// [requireAncestorPointersInfoOwner], to our descendants.
		while (currentContext.isActive) {
		// During the Initial pass, we receive the event after our ancestors.
		val pointers = awaitPointerEvent(PointerEventPass.Initial).changes
		pointersDown = pointers.countDown()
		if (pointersDown == 0) {
		// There are no more pointers down
		val changes = awaitPointerEvent(PointerEventPass.Initial).changes
		pointersDown = changes.countDown()

		when {
		// There are no more pointers down.
		pointersDown == 0 -> {
		startedPosition = null
		} else if (startedPosition == null) {
		startedPosition = pointers.first().position

		// This is the last pointer up
		velocityTracker.addPointerInputChange(changes.single())
		}

		// The first pointer down, startedPosition was not set.
		startedPosition == null -> {
		val firstPointerDown = changes.single()
		velocityPointerId = firstPointerDown.id
		velocityTracker.resetTracking()
		velocityTracker.addPointerInputChange(firstPointerDown)
		startedPosition = firstPointerDown.position
		if (enabled()) {
		onFirstPointerDown()
		}
		}

		// Changes with at least one pointer
		else -> {
		val pointerChange = changes.first()

		// Assuming that the list of changes doesn't have two changes with the same
		// id (PointerId), we can check:
		// - If the first change has `id` equals to `velocityPointerId` (this should
		// always be true unless the pointer has been removed).
		// - If it does, we've found our change event (assuming there aren't any
		// others changes with the same id in this PointerEvent - not checked).
		// - If it doesn't, we can check that the change with that id isn't in first
		// place (which should never happen - this will crash).
		check(
		pointerChange.id == velocityPointerId \|\|
		!changes.fastAny { it.id == velocityPointerId }
		) {
		"$velocityPointerId is present, but not the first: $changes"
		}

		// If the previous pointer has been removed, we use the first available
		// change to keep tracking the velocity.
		velocityPointerId = pointerChange.id

		velocityTracker.addPointerInputChange(pointerChange)
		}
		}
		}
		}
		}
		@@ -253,11 +293,9 @@ internal class MultiPointerDraggableNode(
		orientation = orientation,
		startDragImmediately = startDragImmediately,
		onDragStart = { startedPosition, overSlop, pointersDown ->
		velocityTracker.resetTracking()
		onDragStarted(startedPosition, overSlop, pointersDown)
		},
		onDrag = { controller, change, amount ->
		velocityTracker.addPointerInputChange(change)
		onDrag = { controller, amount ->
		dispatchScrollEvents(
		availableOnPreScroll = amount,
		onScroll = { controller.onDrag(it) },
		@@ -403,7 +441,7 @@ internal class MultiPointerDraggableNode(
		startDragImmediately: (startedPosition: Offset) -> Boolean,
		onDragStart:
		(startedPosition: Offset, overSlop: Float, pointersDown: Int) -> DragController,
		onDrag: (controller: DragController, change: PointerInputChange, dragAmount: Float) -> Unit,
		onDrag: (controller: DragController, dragAmount: Float) -> Unit,
		onDragEnd: (controller: DragController) -> Unit,
		onDragCancel: (controller: DragController) -> Unit,
		swipeDetector: SwipeDetector,
		@@ -482,14 +520,14 @@ internal class MultiPointerDraggableNode(

		val successful: Boolean
		try {
		onDrag(controller, drag, overSlop)
		onDrag(controller, overSlop)

		successful =
		drag(
		initialPointerId = drag.id,
		hasDragged = { it.positionChangeIgnoreConsumed().toFloat() != 0f },
		onDrag = {
		onDrag(controller, it, it.positionChange().toFloat())
		onDrag(controller, it.positionChange().toFloat())
		it.consume()
		},
		onIgnoredEvent = {

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

+87 −0

Original line number	Diff line number	Diff line
		@@ -38,12 +38,15 @@ import androidx.compose.ui.input.pointer.PointerInputChange
		import androidx.compose.ui.input.pointer.pointerInput
		import androidx.compose.ui.platform.LocalDensity
		import androidx.compose.ui.platform.LocalViewConfiguration
		import androidx.compose.ui.test.TouchInjectionScope
		import androidx.compose.ui.test.junit4.createComposeRule
		import androidx.compose.ui.test.onRoot
		import androidx.compose.ui.test.performTouchInput
		import androidx.compose.ui.unit.Density
		import androidx.compose.ui.unit.Velocity
		import androidx.test.ext.junit.runners.AndroidJUnit4
		import com.google.common.truth.Truth.assertThat
		import kotlin.properties.Delegates
		import kotlinx.coroutines.coroutineScope
		import kotlinx.coroutines.isActive
		import org.junit.Rule
		@@ -719,4 +722,88 @@ class MultiPointerDraggableTest {
		assertThat(availableOnPreFling).isEqualTo(consumedOnDragStop)
		assertThat(availableOnPostFling).isEqualTo(0f)
		}

		@Test
		fun multiPointerOnStopVelocity() {
		val size = 200f
		val middle = Offset(size / 2f, size / 2f)

		var stopped = false
		var lastVelocity = -1f
		var touchSlop = 0f
		var density: Density by Delegates.notNull()
		rule.setContent {
		touchSlop = LocalViewConfiguration.current.touchSlop
		density = LocalDensity.current
		Box(
		Modifier.size(with(density) { Size(size, size).toDpSize() })
		.nestedScrollDispatcher()
		.multiPointerDraggable(
		orientation = Orientation.Vertical,
		enabled = { true },
		startDragImmediately = { false },
		onDragStarted = { _, _, _ ->
		SimpleDragController(
		onDrag = { /* do nothing */ },
		onStop = {
		stopped = true
		lastVelocity = it
		},
		)
		},
		dispatcher = defaultDispatcher,
		)
		)
		}

		var eventMillis: Long by Delegates.notNull()
		rule.onRoot().performTouchInput { eventMillis = eventPeriodMillis }

		fun swipeGesture(block: TouchInjectionScope.() -> Unit) {
		stopped = false
		rule.onRoot().performTouchInput {
		down(middle)
		block()
		up()
		}
		assertThat(stopped).isEqualTo(true)
		}

		val shortDistance = touchSlop / 2f
		swipeGesture {
		moveBy(delta = Offset(0f, shortDistance), delayMillis = eventMillis)
		moveBy(delta = Offset(0f, shortDistance), delayMillis = eventMillis)
		}
		assertThat(lastVelocity).isGreaterThan(0f)
		assertThat(lastVelocity).isWithin(1f).of((shortDistance / eventMillis) * 1000f)

		val longDistance = touchSlop * 4f
		swipeGesture {
		moveBy(delta = Offset(0f, longDistance), delayMillis = eventMillis)
		moveBy(delta = Offset(0f, longDistance), delayMillis = eventMillis)
		}
		assertThat(lastVelocity).isGreaterThan(0f)
		assertThat(lastVelocity).isWithin(1f).of((longDistance / eventMillis) * 1000f)

		rule.onRoot().performTouchInput {
		down(pointerId = 0, position = middle)
		down(pointerId = 1, position = middle)
		moveBy(pointerId = 0, delta = Offset(0f, longDistance), delayMillis = eventMillis)
		moveBy(pointerId = 0, delta = Offset(0f, longDistance), delayMillis = eventMillis)
		// The velocity should be:
		// (longDistance / eventMillis) pixels/ms

		// 1 pointer left, the second one
		up(pointerId = 0)

		// After a few events the velocity should be:
		// (shortDistance / eventMillis) pixels/ms
		repeat(10) {
		moveBy(pointerId = 1, delta = Offset(0f, shortDistance), delayMillis = eventMillis)
		}
		up(pointerId = 1)
		}
		assertThat(lastVelocity).isGreaterThan(0f)
		assertThat(lastVelocity).isWithin(1f).of((shortDistance / eventMillis) * 1000f)
		}
		}