Add ReactCompoundViewGroup interface that allows having both virtual …

…and non-virtual (View) children

Summary: In React, ReactCompoundView is supposed to be implemented by a View, but there is no ViewGroup counterpart that allows mixing virual nodes and non-virtual ones (Views) in the same parent. This is needed because TouchTargetHelper always considers child Views when looking for touch target before falling back to View/ReactCompoundView. This works incorrectly for e.g. layout-only / flattened nodes. ReactCompoundViewGroup allow intercepting touch event before it is dispatched to its children. In that sense, ReactCompoundView.reactTagForTouch() is like View.onTouchEvent() whereas ReactCompoundViewGroup.interceptsTouchEvent() is like ViewGroup.onInterceptTouchEvent().

Differential Revision: D3018028

fb-gh-sync-id: d2c70a55afb9ce9823275e7483d72e0ebedf52e4
shipit-source-id: d2c70a55afb9ce9823275e7483d72e0ebedf52e4

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

@@ -0,0 +1,24 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+package com.facebook.react.uimanager;
+
+/**
+ * This interface should be implemented be native ViewGroup subclasses that can represent more
+ * than a single react node. In that case, virtual and non-virtual (mapping to a View) elements
+ * can overlap, and TouchTargetHelper may incorrectly dispatch touch event to a wrong element
+ * because it priorities children over parents.
+ */
+public interface ReactCompoundViewGroup extends ReactCompoundView {
+  /**
+   * Returns true if react node responsible for the touch even is flattened into this ViewGroup.
+   * Use reactTagForTouch() to get its tag.
+   */
+  boolean interceptsTouchEvent(float touchX, float touchY);
+}

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

@@ -209,6 +209,11 @@ private static boolean isTransformedTouchPointInView(
 
     } else if (pointerEvents == PointerEvents.AUTO) {
       // Either this view or one of its children is the target
+      if (view instanceof ReactCompoundViewGroup) {
+        if (((ReactCompoundViewGroup) view).interceptsTouchEvent(eventCoords[0], eventCoords[1])) {
+          return view;
+        }
+      }
       if (view instanceof ViewGroup) {
         return findTouchTargetView(eventCoords, (ViewGroup) view);
       }