Fix touches with pointer events backtrack

Differential Revision: D2553642

fb-gh-sync-id: b1788879bfbb564a291ada0e7ac206f567780f8a

ReactAndroid/src/main/java/com/facebook/react/uimanager/TouchTargetHelper.java

@@ -11,7 +11,6 @@ package com.facebook.react.uimanager;
 
 import javax.annotation.Nullable;
 
-import android.graphics.Rect;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewGroup;
@@ -25,8 +24,7 @@ import com.facebook.react.bridge.UiThreadUtil;
  */
 public class TouchTargetHelper {
 
-  private static final Rect mVisibleRect = new Rect();
-  private static final int[] mViewLocationInScreen = {0, 0};
+  private static final float[] mEventCoords = new float[2];
 
   /**
    * Find touch event target view within the provided container given the coordinates provided
@@ -43,11 +41,15 @@ public class TouchTargetHelper {
       ViewGroup viewGroup) {
     UiThreadUtil.assertOnUiThread();
     int targetTag = viewGroup.getId();
-    View nativeTargetView = findTouchTargetView(eventX, eventY, viewGroup);
+    // Store eventCoords in array so that they are modified to be relative to the targetView found.
+    float[] eventCoords = mEventCoords;
+    eventCoords[0] = eventY;
+    eventCoords[1] = eventX;
+    View nativeTargetView = findTouchTargetView(eventCoords, viewGroup);
     if (nativeTargetView != null) {
       View reactTargetView = findClosestReactAncestor(nativeTargetView);
       if (reactTargetView != null) {
-        targetTag = getTouchTargetForView(reactTargetView, eventX, eventY);
+        targetTag = getTouchTargetForView(reactTargetView, eventCoords[0], eventCoords[1]);
       }
     }
     return targetTag;
@@ -68,38 +70,36 @@ public class TouchTargetHelper {
    * A (pointerEvents: auto) - B (pointerEvents: box-none) - C (pointerEvents: none)
    *  \ D (pointerEvents: auto)  - E (pointerEvents: auto)
    * If the search goes down the first branch, it would return A as the target, which is incorrect.
-   * NB: This method is not thread-safe as it uses static instance of {@link Rect}
+   * NB: This modifies the eventCoords to always be relative to the current viewGroup. When the
+   * method returns, it will contain the eventCoords relative to the targetView found.
    */
-  private static View findTouchTargetView(float eventX, float eventY, ViewGroup viewGroup) {
+  private static View findTouchTargetView(float[] eventCoords, ViewGroup viewGroup) {
     int childrenCount = viewGroup.getChildCount();
     for (int i = childrenCount - 1; i >= 0; i--) {
       View child = viewGroup.getChildAt(i);
-      // Views with `removeClippedSubviews` are exposing removed subviews through `getChildAt` to
-      // support proper view cleanup. Views removed by this option will be detached from it's
-      // parent, therefore `getGlobalVisibleRect` call will return bogus result as it treat view
-      // with no parent as a root of the view hierarchy. To prevent this from happening we check
-      // that view has a parent before visiting it.
-      if (child.getParent() != null && isTouchPointInView(eventX, eventY, viewGroup, child)) {
+      if (isTouchPointInView(eventCoords[0], eventCoords[1], viewGroup, child)) {
         // Apply offset to event coordinates to transform them into the coordinate space of the
         // child view, taken from {@link ViewGroup#dispatchTransformedTouchEvent()}.
-        eventX += viewGroup.getScrollX() - child.getLeft();
-        eventY += viewGroup.getScrollY() - child.getTop();
-        View targetView = findTouchTargetViewWithPointerEvents(eventX, eventY, child);
+        eventCoords[0] += viewGroup.getScrollY() - child.getTop();
+        eventCoords[1] += viewGroup.getScrollX() - child.getLeft();
+        View targetView = findTouchTargetViewWithPointerEvents(eventCoords, child);
         if (targetView != null) {
           return targetView;
         }
+        eventCoords[0] -= viewGroup.getScrollY() - child.getTop();
+        eventCoords[1] -= viewGroup.getScrollX() - child.getLeft();
       }
     }
     return viewGroup;
 }
 
   // Taken from {@link ViewGroup#isTransformedTouchPointInView()}
-  private static boolean isTouchPointInView(float x, float y, ViewGroup parent, View child) {
-    float localX = x + parent.getScrollX() - child.getLeft();
+  private static boolean isTouchPointInView(float y, float x, ViewGroup parent, View child) {
     float localY = y + parent.getScrollY() - child.getTop();
+    float localX = x + parent.getScrollX() - child.getLeft();
     // Taken from {@link View#pointInView()}.
-    return localX >= 0 && localX < (child.getRight() - child.getLeft())
-        && localY >= 0 && localY < (child.getBottom() - child.getTop());
+    return localY >= 0 && localY < (child.getBottom() - child.getTop())
+        && localX >= 0 && localX < (child.getRight() - child.getLeft());
   }
 
   /**
@@ -107,9 +107,7 @@ public class TouchTargetHelper {
    * its descendants are the touch target.
    */
   private static @Nullable View findTouchTargetViewWithPointerEvents(
-      float eventX,
-      float eventY,
-      View view) {
+      float eventCoords[], View view) {
     PointerEvents pointerEvents = view instanceof ReactPointerEventsView ?
         ((ReactPointerEventsView) view).getPointerEvents() : PointerEvents.AUTO;
     if (pointerEvents == PointerEvents.NONE) {
@@ -123,7 +121,7 @@ public class TouchTargetHelper {
     } else if (pointerEvents == PointerEvents.BOX_NONE) {
       // This view can't be the target, but its children might
       if (view instanceof ViewGroup) {
-        View targetView = findTouchTargetView(eventX, eventY, (ViewGroup) view);
+        View targetView = findTouchTargetView(eventCoords, (ViewGroup) view);
         return targetView != view ? targetView : null;
       }
       return null;
@@ -131,7 +129,7 @@ public class TouchTargetHelper {
     } else if (pointerEvents == PointerEvents.AUTO) {
       // Either this view or one of its children is the target
       if (view instanceof ViewGroup) {
-        return findTouchTargetView(eventX, eventY, (ViewGroup) view);
+        return findTouchTargetView(eventCoords, (ViewGroup) view);
       }
       return view;
 
@@ -141,14 +139,11 @@ public class TouchTargetHelper {
     }
   }
 
-  private static int getTouchTargetForView(View targetView, float eventX, float eventY) {
+  private static int getTouchTargetForView(View targetView, float eventY, float eventX) {
     if (targetView instanceof ReactCompoundView) {
-      // Use coordinates relative to the view. Use getLocationOnScreen() API, which is slightly more
-      // expensive than getGlobalVisibleRect(), otherwise partially visible views offset is wrong.
-      targetView.getLocationOnScreen(mViewLocationInScreen);
-      return ((ReactCompoundView) targetView).reactTagForTouch(
-          eventX - mViewLocationInScreen[0],
-          eventY - mViewLocationInScreen[1]);
+      // Use coordinates relative to the view, which have been already computed by
+      // {@link #findTouchTargetView()}.
+      return ((ReactCompoundView) targetView).reactTagForTouch(eventX, eventY);
     }
     return targetView.getId();
   }

ReactAndroid/src/main/java/com/facebook/react/views/text/ReactTextView.java

@@ -30,12 +30,6 @@ public class ReactTextView extends TextView implements ReactCompoundView {
     int x = (int) touchX;
     int y = (int) touchY;
 
-    x -= getTotalPaddingLeft();
-    y -= getTotalPaddingTop();
-
-    x += getScrollX();
-    y += getScrollY();
-
     Layout layout = getLayout();
     int line = layout.getLineForVertical(y);