Check view drawing order in ViewGroup#getChildLocalHitRegion (3b4c0325) · Commits · e / os / android_frameworks_base

core/java/android/view/ViewGroup.java

+48 −12

Original line number	Diff line number	Diff line
		@@ -7397,19 +7397,26 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager
		}
		target = next;
		}
		if (!childIsHit) {
		if (!childIsHit && mFirstHoverTarget != null) {
		target = mFirstHoverTarget;
		final ArrayList<View> preorderedList = buildTouchDispatchChildList();
		while (notEmpty && target != null) {
		final HoverTarget next = target.next;
		final View hoveredView = target.child;

		if (!isOnTop(child, hoveredView, preorderedList)) {
		rect.set(hoveredView.mLeft, hoveredView.mTop, hoveredView.mRight,
		hoveredView.mBottom);
		matrix.mapRect(rect);
		notEmpty = region.op(Math.round(rect.left), Math.round(rect.top),
		Math.round(rect.right), Math.round(rect.bottom), Region.Op.DIFFERENCE);
		Math.round(rect.right), Math.round(rect.bottom),
		Region.Op.DIFFERENCE);
		}
		target = next;
		}
		if (preorderedList != null) {
		preorderedList.clear();
		}
		}
		} else {
		TouchTarget target = mFirstTouchTarget;
		@@ -7422,19 +7429,26 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager
		}
		target = next;
		}
		if (!childIsHit) {
		if (!childIsHit && mFirstTouchTarget != null) {
		target = mFirstTouchTarget;
		final ArrayList<View> preorderedList = buildOrderedChildList();
		while (notEmpty && target != null) {
		final TouchTarget next = target.next;
		final View touchedView = target.child;

		if (!isOnTop(child, touchedView, preorderedList)) {
		rect.set(touchedView.mLeft, touchedView.mTop, touchedView.mRight,
		touchedView.mBottom);
		matrix.mapRect(rect);
		notEmpty = region.op(Math.round(rect.left), Math.round(rect.top),
		Math.round(rect.right), Math.round(rect.bottom), Region.Op.DIFFERENCE);
		Math.round(rect.right), Math.round(rect.bottom),
		Region.Op.DIFFERENCE);
		}
		target = next;
		}
		if (preorderedList != null) {
		preorderedList.clear();
		}
		}
		}

		@@ -7444,6 +7458,28 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager
		return notEmpty;
		}

		/**
		* Return true if the given {@code view} is drawn on top of the {@code otherView}.
		* Both the {@code view} and {@code otherView} must be children of this ViewGroup.
		* Otherwise, the returned value is meaningless.
		*/
		private boolean isOnTop(View view, View otherView, ArrayList<View> preorderedList) {
		final int childrenCount = mChildrenCount;
		final boolean customOrder = preorderedList == null && isChildrenDrawingOrderEnabled();
		final View[] children = mChildren;
		for (int i = childrenCount - 1; i >= 0; i--) {
		final int childIndex = getAndVerifyPreorderedIndex(childrenCount, i, customOrder);
		final View child = getAndVerifyPreorderedView(preorderedList, children, childIndex);
		if (child == view) {
		return true;
		}
		if (child == otherView) {
		return false;
		}
		}
		// Can't find the view and otherView in the children list. Return value is meaningless.
		return false;
		}

		private static void applyOpToRegionByBounds(Region region, View view, Region.Op op) {
		final int[] locationInWindow = new int[2];

core/tests/coretests/src/android/view/ViewGroupGetChildLocalHitRegionTest.java

+55 −4

Original line number	Diff line number	Diff line
		@@ -90,22 +90,73 @@ public class ViewGroupGetChildLocalHitRegionTest {
		assertGetChildLocalHitRegionEmpty(R.id.view_cover_top, R.id.view_cover_bottom);
		}

		@Test
		public void testGetChildLocalHitRegion_topViewIsNotBlockedByBottomView() {
		// In this case, two views overlap with each other and the MotionEvent is injected to the
		// bottom view. It verifies that the hit region of the top view won't be blocked by the
		// bottom view.
		testGetChildLocalHitRegion_topViewIsNotBlockedByBottomView(/* isHover= */ true);
		testGetChildLocalHitRegion_topViewIsNotBlockedByBottomView(/* isHover= */ false);
		}

		private void testGetChildLocalHitRegion_topViewIsNotBlockedByBottomView(boolean isHover) {
		// In this case, two views overlap with each other and the MotionEvent is injected to the
		// bottom view. It verifies that the hit region of the top view won't be blocked by the
		// bottom view.
		mScenarioRule.getScenario().onActivity(activity -> {
		View viewTop = activity.findViewById(R.id.view_overlap_top);
		View viewBottom = activity.findViewById(R.id.view_overlap_bottom);

		// The viewTop covers the left side of the viewBottom. To avoid the MotionEvent gets
		// blocked by viewTop, we inject MotionEvents into viewBottom's right bottom corner.
		float x = viewBottom.getWidth() - 1;
		float y = viewBottom.getHeight() - 1;
		injectMotionEvent(viewBottom, x, y, isHover);

		Matrix actualMatrix = new Matrix();
		Region actualRegion = new Region(0, 0, viewTop.getWidth(), viewTop.getHeight());
		boolean actualNotEmpty = viewTop.getParent()
		.getChildLocalHitRegion(viewTop, actualRegion, actualMatrix, isHover);

		int[] windowLocation = new int[2];
		viewTop.getLocationInWindow(windowLocation);
		Matrix expectMatrix = new Matrix();
		expectMatrix.preTranslate(-windowLocation[0], -windowLocation[1]);
		// Though viewTop and viewBottom overlaps, viewTop's hit region won't be blocked by
		// viewBottom.
		Region expectRegion = new Region(0, 0, viewTop.getWidth(), viewTop.getHeight());

		assertThat(actualNotEmpty).isTrue();
		assertThat(actualMatrix).isEqualTo(expectMatrix);
		assertThat(actualRegion).isEqualTo(expectRegion);
		});
		}

		private void injectMotionEvent(View view, boolean isHover) {
		float x = view.getWidth() / 2f;
		float y = view.getHeight() / 2f;
		injectMotionEvent(view, x, y, isHover);
		}

		/**
		* Inject MotionEvent into the given view, at the given location specified in the view's
		* coordinates.
		*/
		private void injectMotionEvent(View view, float x, float y, boolean isHover) {
		int[] location = new int[2];
		view.getLocationInWindow(location);

		float x = location[0] + view.getWidth() / 2f;
		float y = location[1] + view.getHeight() / 2f;
		float globalX = location[0] + x;
		float globalY = location[1] + y;

		int action = isHover ? MotionEvent.ACTION_HOVER_ENTER : MotionEvent.ACTION_DOWN;
		MotionEvent motionEvent = MotionEvent.obtain(/* downtime= / 0, / eventTime= */ 0, action,
		x, y, /* pressure= / 0, / size= / 0, / metaState= */ 0,
		globalX, globalY, /* pressure= / 0, / size= / 0, / metaState= */ 0,
		/* xPrecision= / 1, / yPrecision= / 1, / deviceId= /0, / edgeFlags= */0);

		View rootView = view.getRootView();
		rootView.dispatchPointerEvent(motionEvent);
		}

		private void assertGetChildLocalHitRegion(int viewId) {
		assertGetChildLocalHitRegion(viewId, /* isHover= */ true);
		assertGetChildLocalHitRegion(viewId, /* isHover= */ false);