Add NestedDraggable.shouldConsumeNestedPreScroll() (6b7574f3) · Commits · e / os / android_frameworks_base

packages/SystemUI/compose/core/src/com/android/compose/gesture/NestedDraggable.kt

+44 −20

Original line number	Diff line number	Diff line
		@@ -95,10 +95,20 @@ interface NestedDraggable {
		* nested scrollable.
		*
		* This is called whenever a nested scrollable does not consume some scroll amount. If this
		* returns `true`, then [onDragStarted] will be called and this draggable will have priority and
		* returns `true`, then [onDragStarted] will be called, this draggable will have priority and
		* consume all future events during preScroll until the nested scroll is finished.
		*/
		fun shouldConsumeNestedScroll(sign: Float): Boolean
		fun shouldConsumeNestedPostScroll(sign: Float): Boolean = true

		/**
		* Whether this draggable should consume any scroll amount with the given [sign] before it can
		* be consumed by a nested scrollable.
		*
		* This is called before a nested scrollable is able to consume that scroll amount. If this
		* returns `true`, then [onDragStarted] will be called, this draggable will have priority and
		* consume all future scroll events during preScroll until the nested scroll is finished.
		*/
		fun shouldConsumeNestedPreScroll(sign: Float): Boolean = false

		interface Controller {
		/**
		@@ -540,6 +550,14 @@ private class NestedDraggableNode(
		}

		override fun onPreScroll(available: Offset, source: NestedScrollSource): Offset {
		val sign = available.toFloat().sign
		maybeCreateNewController(
		sign = sign,
		condition = {
		source == NestedScrollSource.UserInput &&
		draggable.shouldConsumeNestedPreScroll(sign)
		},
		)
		val controller = nestedScrollController ?: return Offset.Zero
		return scrollWithOverscroll(controller, available)
		}
		@@ -560,19 +578,29 @@ private class NestedDraggableNode(
		}

		val sign = offset.sign
		maybeCreateNewController(
		sign,
		condition = { draggable.shouldConsumeNestedPostScroll(sign) },
		)
		val controller = nestedScrollController ?: return Offset.Zero
		return scrollWithOverscroll(controller, available)
		}

		private fun maybeCreateNewController(sign: Float, condition: () -> Boolean) {
		if (
		nestedDragsEnabled &&
		nestedScrollController == null &&
		// TODO(b/388231324): Remove this.
		!lastEventWasScrollWheel &&
		draggable.shouldConsumeNestedScroll(sign) &&
		lastFirstDown != null
		!nestedDragsEnabled \|\|
		nestedScrollController != null \|\|
		lastEventWasScrollWheel \|\|
		lastFirstDown == null \|\|
		!condition()
		) {
		val startedPosition = checkNotNull(lastFirstDown)
		return
		}

		// TODO(b/382665591): Ensure that there is at least one pointer down.
		val pointersDownCount = pointersDown.size.coerceAtLeast(1)
		val pointerType = pointersDown.entries.firstOrNull()?.value
		val startedPosition = checkNotNull(lastFirstDown)
		nestedScrollController =
		NestedScrollController(
		overscrollEffect,
		@@ -580,10 +608,6 @@ private class NestedDraggableNode(
		)
		}

		val controller = nestedScrollController ?: return Offset.Zero
		return scrollWithOverscroll(controller, available)
		}

		private fun scrollWithOverscroll(controller: NestedScrollController, offset: Offset): Offset {
		return scrollWithOverscroll(offset) {
		controller.controller.onDrag(it.toFloat()).toOffset()

packages/SystemUI/compose/core/tests/src/com/android/compose/gesture/NestedDraggableTest.kt

+37 −3

Original line number	Diff line number	Diff line
		@@ -971,6 +971,35 @@ class NestedDraggableTest(override val orientation: Orientation) : OrientationAw
		assertThat(availableToEffectPostFling).isWithin(1f).of(100f)
		}

		@Test
		fun consumeNestedPreScroll() {
		var consumeNestedPreScroll by mutableStateOf(false)
		val draggable = TestDraggable(shouldConsumeNestedPreScroll = { consumeNestedPreScroll })

		val touchSlop =
		rule.setContentWithTouchSlop {
		Box(
		Modifier.fillMaxSize()
		.nestedDraggable(draggable, orientation)
		// Always consume everything so that the only way to start the drag is to
		// intercept preScroll events.
		.scrollable(rememberScrollableState { it }, orientation)
		)
		}

		rule.onRoot().performTouchInput {
		down(center)
		moveBy((touchSlop + 1f).toOffset())
		}

		assertThat(draggable.onDragStartedCalled).isFalse()

		consumeNestedPreScroll = true
		rule.onRoot().performTouchInput { moveBy(1f.toOffset()) }

		assertThat(draggable.onDragStartedCalled).isTrue()
		}

		private fun ComposeContentTestRule.setContentWithTouchSlop(
		content: @Composable () -> Unit
		): Float {
		@@ -996,7 +1025,8 @@ class NestedDraggableTest(override val orientation: Orientation) : OrientationAw
		{ velocity, _ ->
		velocity
		},
		private val shouldConsumeNestedScroll: (Float) -> Boolean = { true },
		private val shouldConsumeNestedPostScroll: (Float) -> Boolean = { true },
		private val shouldConsumeNestedPreScroll: (Float) -> Boolean = { false },
		) : NestedDraggable {
		var shouldStartDrag = true
		var onDragStartedCalled = false
		@@ -1042,8 +1072,12 @@ class NestedDraggableTest(override val orientation: Orientation) : OrientationAw
		}
		}

		override fun shouldConsumeNestedScroll(sign: Float): Boolean {
		return shouldConsumeNestedScroll.invoke(sign)
		override fun shouldConsumeNestedPostScroll(sign: Float): Boolean {
		return shouldConsumeNestedPostScroll.invoke(sign)
		}

		override fun shouldConsumeNestedPreScroll(sign: Float): Boolean {
		return shouldConsumeNestedPreScroll.invoke(sign)
		}
		}
		}

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

+1 −1

Original line number	Diff line number	Diff line
		@@ -68,7 +68,7 @@ internal class DraggableHandler(
		return layoutImpl.swipeDetector.detectSwipe(change)
		}

		override fun shouldConsumeNestedScroll(sign: Float): Boolean {
		override fun shouldConsumeNestedPostScroll(sign: Float): Boolean {
		return this.enabled()
		}