Merge "Drag events can only start if there is at least one pointer down." into main (3b7c2e6b) · Commits · e / os / android_frameworks_base

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

+11 −9

Original line number	Diff line number	Diff line
		@@ -362,11 +362,13 @@ internal class MultiPointerDraggableNode(
		pass: () -> PointerEventPass,
		): PointerEvent {
		fun canBeConsumed(changes: List<PointerInputChange>): Boolean {
		// At least one pointer down AND
		return changes.fastAny { it.pressed } &&
		// 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.
		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

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

+74 −0

Original line number	Diff line number	Diff line
		@@ -120,6 +120,80 @@ class MultiPointerDraggableTest {
		assertThat(stopped).isTrue()
		}

		@Test
		fun shouldNotStartDragEventsWith0PointersDown() {
		val size = 200f
		val middle = Offset(size / 2f, size / 2f)

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

		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 = { true },
		onDragStarted = { _, _, _ ->
		started = true
		object : DragController {
		override fun onDrag(delta: Float) {
		dragged = true
		}

		override fun onStop(velocity: Float, canChangeScene: Boolean) {
		stopped = true
		}
		}
		},
		)
		.pointerInput(Unit) {
		coroutineScope {
		awaitPointerEventScope {
		while (isActive) {
		val change = awaitPointerEvent().changes.first()
		if (consumeBeforeMultiPointerDraggable) {
		change.consume()
		}
		}
		}
		}
		}
		)
		}

		// The first part of the gesture is consumed by our descendant
		consumeBeforeMultiPointerDraggable = true
		rule.onRoot().performTouchInput {
		down(middle)
		moveBy(Offset(0f, touchSlop))
		}

		started = false
		dragged = false
		stopped = false

		// The next events could be consumed by us
		consumeBeforeMultiPointerDraggable = false
		rule.onRoot().performTouchInput {
		// The pointer is moved to a new position without reporting it
		updatePointerBy(0, Offset(0f, touchSlop))

		// The pointer report an "up" (0 pointers down) with a new position
		up()
		}

		// This event should not be used to start a drag gesture
		assertThat(started).isFalse()
		assertThat(dragged).isFalse()
		assertThat(stopped).isFalse()
		}

		@Test
		fun handleDisappearingScrollableDuringAGesture() {
		val size = 200f