[STL] handling scenarios where scrollable elements disappear (de93b945) · Commits · e / os / android_frameworks_base

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

+115 −66

Original line number	Diff line number	Diff line
		@@ -17,8 +17,6 @@
		package com.android.compose.animation.scene

		import androidx.compose.foundation.gestures.Orientation
		import androidx.compose.foundation.gestures.awaitEachGesture
		import androidx.compose.foundation.gestures.awaitFirstDown
		import androidx.compose.foundation.gestures.awaitHorizontalTouchSlopOrCancellation
		import androidx.compose.foundation.gestures.awaitVerticalTouchSlopOrCancellation
		import androidx.compose.foundation.gestures.horizontalDrag
		@@ -26,12 +24,14 @@ import androidx.compose.foundation.gestures.verticalDrag
		import androidx.compose.runtime.Stable
		import androidx.compose.ui.Modifier
		import androidx.compose.ui.geometry.Offset
		import androidx.compose.ui.input.pointer.AwaitPointerEventScope
		import androidx.compose.ui.input.pointer.PointerEvent
		import androidx.compose.ui.input.pointer.PointerEventPass
		import androidx.compose.ui.input.pointer.PointerId
		import androidx.compose.ui.input.pointer.PointerInputChange
		import androidx.compose.ui.input.pointer.PointerInputScope
		import androidx.compose.ui.input.pointer.SuspendingPointerInputModifierNode
		import androidx.compose.ui.input.pointer.changedToDownIgnoreConsumed
		import androidx.compose.ui.input.pointer.positionChange
		import androidx.compose.ui.input.pointer.util.VelocityTracker
		import androidx.compose.ui.input.pointer.util.addPointerInputChange
		@@ -45,8 +45,12 @@ import androidx.compose.ui.node.observeReads
		import androidx.compose.ui.platform.LocalViewConfiguration
		import androidx.compose.ui.unit.IntSize
		import androidx.compose.ui.unit.Velocity
		import androidx.compose.ui.util.fastAll
		import androidx.compose.ui.util.fastForEach
		import kotlin.coroutines.cancellation.CancellationException
		import kotlin.math.sign
		import kotlinx.coroutines.coroutineScope
		import kotlinx.coroutines.isActive

		/**
		* Make an element draggable in the given [orientation].
		@@ -163,6 +167,10 @@ internal class MultiPointerDraggableNode(
		return
		}

		coroutineScope {
		awaitPointerEventScope {
		while (isActive) {
		try {
		detectDragGestures(
		orientation = orientation,
		startDragImmediately = startDragImmediately,
		@@ -176,7 +184,8 @@ internal class MultiPointerDraggableNode(
		},
		onDragEnd = { controller ->
		val viewConfiguration = currentValueOf(LocalViewConfiguration)
		val maxVelocity = viewConfiguration.maximumFlingVelocity.let { Velocity(it, it) }
		val maxVelocity =
		viewConfiguration.maximumFlingVelocity.let { Velocity(it, it) }
		val velocity = velocityTracker.calculateVelocity(maxVelocity)
		controller.onStop(
		velocity =
		@@ -191,6 +200,14 @@ internal class MultiPointerDraggableNode(
		controller.onStop(velocity = 0f, canChangeScene = true)
		},
		)
		} catch (exception: CancellationException) {
		// If the coroutine scope is active, we can just restart the drag cycle.
		if (!isActive) {
		throw exception
		}
		}
		}
		}
		}
		}

		@@ -202,36 +219,43 @@ internal class MultiPointerDraggableNode(
		* 1) starting the gesture immediately without requiring a drag >= touch slope;
		* 2) passing the number of pointers down to [onDragStart].
		*/
		private suspend fun PointerInputScope.detectDragGestures(
		private suspend fun AwaitPointerEventScope.detectDragGestures(
		orientation: Orientation,
		startDragImmediately: (startedPosition: Offset) -> Boolean,
		onDragStart: (startedPosition: Offset, overSlop: Float, pointersDown: Int) -> DragController,
		onDragEnd: (controller: DragController) -> Unit,
		onDragCancel: (controller: DragController) -> Unit,
		onDragStart:
		(startedPosition: Offset, overSlop: Float, pointersDown: Int) -> DragController,
		onDrag: (controller: DragController, change: PointerInputChange, dragAmount: Float) -> Unit,
		onDragEnd: (controller: DragController) -> Unit,
		onDragCancel: (controller: DragController) -> Unit
		) {
		awaitEachGesture {
		val initialDown = awaitFirstDown(requireUnconsumed = false, pass = PointerEventPass.Initial)
		// Wait for a consumable event in [PointerEventPass.Main] pass
		val consumablePointer = awaitConsumableEvent().changes.first()

		var overSlop = 0f
		val drag =
		if (startDragImmediately(initialDown.position)) {
		initialDown.consume()
		initialDown
		if (startDragImmediately(consumablePointer.position)) {
		consumablePointer.consume()
		consumablePointer
		} else {
		val down = awaitFirstDown(requireUnconsumed = false)
		val onSlopReached = { change: PointerInputChange, over: Float ->
		change.consume()
		overSlop = over
		}

		// TODO(b/291055080): Replace by await[Orientation]PointerSlopOrCancellation once
		// it is public.
		// TODO(b/291055080): Replace by await[Orientation]PointerSlopOrCancellation once it
		// is public.
		val drag =
		when (orientation) {
		Orientation.Horizontal ->
		awaitHorizontalTouchSlopOrCancellation(down.id, onSlopReached)
		awaitHorizontalTouchSlopOrCancellation(
		consumablePointer.id,
		onSlopReached
		)
		Orientation.Vertical ->
		awaitVerticalTouchSlopOrCancellation(down.id, onSlopReached)
		awaitVerticalTouchSlopOrCancellation(
		consumablePointer.id,
		onSlopReached
		)
		}

		// Make sure that overSlop is not 0f. This can happen when the user drags by exactly
		@@ -240,16 +264,10 @@ private suspend fun PointerInputScope.detectDragGestures(
		// we intercept an ongoing swipe transition (i.e. startDragImmediately() returned
		// true).
		if (drag != null && overSlop == 0f) {
		val deltaOffset = drag.position - initialDown.position
		val delta =
		when (orientation) {
		Orientation.Horizontal -> deltaOffset.x
		Orientation.Vertical -> deltaOffset.y
		}
		val delta = (drag.position - consumablePointer.position).toFloat()
		check(delta != 0f) { "delta is equal to 0" }
		overSlop = delta.sign
		}

		drag
		}

		@@ -272,12 +290,12 @@ private suspend fun PointerInputScope.detectDragGestures(
		when (orientation) {
		Orientation.Horizontal ->
		horizontalDrag(drag.id) {
		onDrag(controller, it, it.positionChange().x)
		onDrag(controller, it, it.positionChange().toFloat())
		it.consume()
		}
		Orientation.Vertical ->
		verticalDrag(drag.id) {
		onDrag(controller, it, it.positionChange().y)
		onDrag(controller, it, it.positionChange().toFloat())
		it.consume()
		}
		}
		@@ -293,4 +311,35 @@ private suspend fun PointerInputScope.detectDragGestures(
		}
		}
		}

		private suspend fun AwaitPointerEventScope.awaitConsumableEvent(): PointerEvent {
		fun canBeConsumed(changes: List<PointerInputChange>): Boolean {
		// All pointers must be:
		return changes.fastAll {
		// A) recently pressed: even if the event has already been consumed, we can still
		// use the recently added finger event to determine whether to initiate dragging the
		// scene.
		it.changedToDownIgnoreConsumed() \|\|
		// B) unconsumed AND in a new position (on the current axis)
		it.positionChange().toFloat() != 0f
		}
		}

		var event: PointerEvent
		do {
		// To allow the descendants with the opportunity to consume the event, we wait for it in
		// the Main pass.
		event = awaitPointerEvent()
		} while (!canBeConsumed(event.changes))

		// We found a consumable event in the Main pass
		return event
		}

		private fun Offset.toFloat(): Float {
		return when (orientation) {
		Orientation.Vertical -> y
		Orientation.Horizontal -> x
		}
		}
		}

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

+236 −0

Original line number	Diff line number	Diff line
		@@ -17,7 +17,10 @@
		package com.android.compose.animation.scene

		import androidx.compose.foundation.gestures.Orientation
		import androidx.compose.foundation.gestures.rememberScrollableState
		import androidx.compose.foundation.gestures.scrollable
		import androidx.compose.foundation.layout.Box
		import androidx.compose.foundation.layout.fillMaxSize
		import androidx.compose.foundation.layout.size
		import androidx.compose.runtime.getValue
		import androidx.compose.runtime.mutableStateOf
		@@ -25,6 +28,9 @@ import androidx.compose.runtime.setValue
		import androidx.compose.ui.Modifier
		import androidx.compose.ui.geometry.Offset
		import androidx.compose.ui.geometry.Size
		import androidx.compose.ui.input.pointer.AwaitPointerEventScope
		import androidx.compose.ui.input.pointer.PointerEventPass
		import androidx.compose.ui.input.pointer.pointerInput
		import androidx.compose.ui.platform.LocalDensity
		import androidx.compose.ui.platform.LocalViewConfiguration
		import androidx.compose.ui.test.junit4.createComposeRule
		@@ -32,6 +38,8 @@ import androidx.compose.ui.test.onRoot
		import androidx.compose.ui.test.performTouchInput
		import androidx.test.ext.junit.runners.AndroidJUnit4
		import com.google.common.truth.Truth.assertThat
		import kotlinx.coroutines.coroutineScope
		import kotlinx.coroutines.isActive
		import org.junit.Rule
		import org.junit.Test
		import org.junit.runner.RunWith
		@@ -110,4 +118,232 @@ class MultiPointerDraggableTest {
		assertThat(dragged).isTrue()
		assertThat(stopped).isTrue()
		}

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

		var started = false
		var dragged = false
		var stopped = false
		var consumedByScroll = false
		var hasScrollable by mutableStateOf(true)

		var touchSlop = 0f
		rule.setContent {
		touchSlop = LocalViewConfiguration.current.touchSlop
		Box(
		Modifier.size(with(LocalDensity.current) { Size(size, size).toDpSize() })
		.multiPointerDraggable(
		orientation = Orientation.Vertical,
		enabled = { true },
		startDragImmediately = { false },
		onDragStarted = { _, _, _ ->
		started = true
		object : DragController {
		override fun onDrag(delta: Float) {
		dragged = true
		}

		override fun onStop(velocity: Float, canChangeScene: Boolean) {
		stopped = true
		}
		}
		},
		)
		) {
		if (hasScrollable) {
		Box(
		Modifier.scrollable(
		// Consume all the vertical scroll gestures
		rememberScrollableState(
		consumeScrollDelta = {
		consumedByScroll = true
		it
		}
		),
		Orientation.Vertical
		)
		.fillMaxSize()
		)
		}
		}
		}

		fun startDraggingDown() {
		rule.onRoot().performTouchInput {
		down(middle)
		moveBy(Offset(0f, touchSlop))
		}
		}

		fun continueDraggingDown() {
		rule.onRoot().performTouchInput { moveBy(Offset(0f, touchSlop)) }
		}

		fun releaseFinger() {
		rule.onRoot().performTouchInput { up() }
		}

		// Swipe down. This should intercepted by the scrollable modifier.
		startDraggingDown()
		assertThat(consumedByScroll).isTrue()
		assertThat(started).isFalse()
		assertThat(dragged).isFalse()
		assertThat(stopped).isFalse()

		// Reset the scroll state for the test
		consumedByScroll = false

		// Suddenly remove the scrollable container
		hasScrollable = false
		rule.waitForIdle()

		// Swipe down. This will be intercepted by multiPointerDraggable, it will wait touchSlop
		// before consuming it.
		continueDraggingDown()
		assertThat(consumedByScroll).isFalse()
		assertThat(started).isFalse()
		assertThat(dragged).isFalse()
		assertThat(stopped).isFalse()

		// Swipe down. This should both call onDragStarted() and onDragDelta().
		continueDraggingDown()
		assertThat(consumedByScroll).isFalse()
		assertThat(started).isTrue()
		assertThat(dragged).isTrue()
		assertThat(stopped).isFalse()

		rule.waitForIdle()
		releaseFinger()
		assertThat(stopped).isTrue()
		}

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

		var started = false
		var dragged = false
		var stopped = false

		var childConsumesOnPass: PointerEventPass? = null

		suspend fun AwaitPointerEventScope.childPointerInputScope() {
		awaitPointerEvent(PointerEventPass.Initial).also { initial ->
		// Check unconsumed: it should be always true
		assertThat(initial.changes.any { it.isConsumed }).isFalse()

		if (childConsumesOnPass == PointerEventPass.Initial) {
		initial.changes.first().consume()
		}
		}

		awaitPointerEvent(PointerEventPass.Main).also { main ->
		// Check unconsumed
		if (childConsumesOnPass != PointerEventPass.Initial) {
		assertThat(main.changes.any { it.isConsumed }).isFalse()
		}

		if (childConsumesOnPass == PointerEventPass.Main) {
		main.changes.first().consume()
		}
		}
		}

		var touchSlop = 0f
		rule.setContent {
		touchSlop = LocalViewConfiguration.current.touchSlop
		Box(
		Modifier.size(with(LocalDensity.current) { Size(size, size).toDpSize() })
		.multiPointerDraggable(
		orientation = Orientation.Vertical,
		enabled = { true },
		startDragImmediately = { false },
		onDragStarted = { _, _, _ ->
		started = true
		object : DragController {
		override fun onDrag(delta: Float) {
		dragged = true
		}

		override fun onStop(velocity: Float, canChangeScene: Boolean) {
		stopped = true
		}
		}
		},
		)
		) {
		Box(
		Modifier.pointerInput(Unit) {
		coroutineScope {
		awaitPointerEventScope {
		while (isActive) {
		childPointerInputScope()
		}
		}
		}
		}
		.fillMaxSize()
		)
		}
		}

		fun startDraggingDown() {
		rule.onRoot().performTouchInput {
		down(middle)
		moveBy(Offset(0f, touchSlop))
		}
		}

		fun continueDraggingDown() {
		rule.onRoot().performTouchInput { moveBy(Offset(0f, touchSlop)) }
		}

		childConsumesOnPass = PointerEventPass.Initial

		startDraggingDown()
		assertThat(started).isFalse()
		assertThat(dragged).isFalse()
		assertThat(stopped).isFalse()

		continueDraggingDown()
		assertThat(started).isFalse()
		assertThat(dragged).isFalse()
		assertThat(stopped).isFalse()

		childConsumesOnPass = PointerEventPass.Main

		continueDraggingDown()
		assertThat(started).isFalse()
		assertThat(dragged).isFalse()
		assertThat(stopped).isFalse()

		continueDraggingDown()
		assertThat(started).isFalse()
		assertThat(dragged).isFalse()
		assertThat(stopped).isFalse()

		childConsumesOnPass = null

		// Swipe down. This will be intercepted by multiPointerDraggable, it will wait touchSlop
		// before consuming it.
		continueDraggingDown()
		assertThat(started).isFalse()
		assertThat(dragged).isFalse()
		assertThat(stopped).isFalse()

		// Swipe down. This should both call onDragStarted() and onDragDelta().
		continueDraggingDown()
		assertThat(started).isTrue()
		assertThat(dragged).isTrue()
		assertThat(stopped).isFalse()

		childConsumesOnPass = PointerEventPass.Main

		continueDraggingDown()
		assertThat(stopped).isTrue()
		}
		}