Support ScrollAway in ReactScrollView

Summary:
Support ScrollAway in ReactScrollView for Fabric/non-Fabric.

Changelog: [Android][Added] Support for ScrollAway native nav bars added to ReactScrollView

Reviewed By: mdvacca

Differential Revision: D28308855

fbshipit-source-id: 9a922159ef50fb7c8e9c484a4b97ca57ab248496

Author: JoshuaGross

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

@@ -43,12 +43,16 @@ public static void calculateClippingRect(View view, Rect outputRect) {
         // Intersect the view with the parent's rectangle
         // This will result in the overlap with coordinates in the parent space
         if (!sHelperRect.intersect(
-            view.getLeft(), view.getTop(), view.getRight(), view.getBottom())) {
+            view.getLeft(),
+            view.getTop() + (int) view.getTranslationY(),
+            view.getRight(),
+            view.getBottom() + (int) view.getTranslationY())) {
           outputRect.setEmpty();
           return;
         }
         // Now we move the coordinates to the View's coordinate space
         sHelperRect.offset(-view.getLeft(), -view.getTop());
+        sHelperRect.offset(-(int) view.getTranslationX(), -(int) view.getTranslationY());
         sHelperRect.offset(view.getScrollX(), view.getScrollY());
         outputRect.set(sHelperRect);
         return;

ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactHorizontalScrollView.java

@@ -60,6 +60,7 @@ public class ReactHorizontalScrollView extends HorizontalScrollView
   private static boolean sTriedToGetScrollerField = false;
   private static final String CONTENT_OFFSET_LEFT = "contentOffsetLeft";
   private static final String CONTENT_OFFSET_TOP = "contentOffsetTop";
+  private static final String SCROLL_AWAY_PADDING_TOP = "scrollAwayPaddingTop";
   private int mLayoutDirection;
 
   private int mScrollXAfterMeasure = NO_SCROLL_POSITION;
@@ -1214,6 +1215,7 @@ public WritableMap getStateUpdate() {
             WritableMap map = new WritableNativeMap();
             map.putDouble(CONTENT_OFFSET_LEFT, PixelUtil.toDIPFromPixel(fabricScrollX));
             map.putDouble(CONTENT_OFFSET_TOP, PixelUtil.toDIPFromPixel(scrollY));
+            map.putDouble(SCROLL_AWAY_PADDING_TOP, 0);
             return map;
           }
         });

ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactScrollView.java

@@ -58,6 +58,7 @@ public class ReactScrollView extends ScrollView
   private static boolean sTriedToGetScrollerField = false;
   private static final String CONTENT_OFFSET_LEFT = "contentOffsetLeft";
   private static final String CONTENT_OFFSET_TOP = "contentOffsetTop";
+  private static final String SCROLL_AWAY_PADDING_TOP = "scrollAwayPaddingTop";
 
   private static final int UNSET_CONTENT_OFFSET = -1;
 
@@ -95,6 +96,8 @@ public class ReactScrollView extends ScrollView
   private int mFinalAnimatedPositionScrollX;
   private int mFinalAnimatedPositionScrollY;
 
+  private int mScrollAwayPaddingTop = 0;
+
   private int mLastStateUpdateScrollX = -1;
   private int mLastStateUpdateScrollY = -1;
 
@@ -959,6 +962,41 @@ public void setBorderStyle(@Nullable String style) {
     mReactBackgroundManager.setBorderStyle(style);
   }
 
+  /**
+   * ScrollAway: This enables a natively-controlled navbar that optionally obscures the top content
+   * of the ScrollView. Whether or not the navbar is obscuring the React Native surface is
+   * determined outside of React Native.
+   *
+   * <p>Note: all ScrollViews and HorizontalScrollViews in React have exactly one child: the
+   * "content" View (see ScrollView.js). That View is non-collapsable so it will never be
+   * View-flattened away. However, it is possible to pass custom styles into that View.
+   *
+   * <p>If you are using this feature it is assumed that you have full control over this ScrollView
+   * and that you are **not** overriding the ScrollView content view to pass in a `translateY`
+   * style. `translateY` must never be set from ReactJS while using this feature!
+   */
+  public void setScrollAwayTopPaddingEnabledUnstable(int topPadding) {
+    int count = getChildCount();
+
+    Assertions.assertCondition(
+        count == 1, "React Native ScrollView always has exactly 1 child; a content View");
+
+    if (count > 0) {
+      for (int i = 0; i < count; i++) {
+        View childView = getChildAt(i);
+        childView.setTranslationY(topPadding);
+      }
+
+      // Add the topPadding value as the bottom padding for the ScrollView.
+      // Otherwise, we'll push down the contents of the scroll view down too
+      // far off screen.
+      setPadding(0, 0, 0, topPadding);
+    }
+
+    updateScrollAwayState(topPadding);
+    setRemoveClippedSubviews(mRemoveClippedSubviews);
+  }
+
   /**
    * Called on any stabilized onScroll change to propagate content offset value to a Shadow Node.
    */
@@ -971,23 +1009,41 @@ private void updateStateOnScroll(final int scrollX, final int scrollY) {
     mLastStateUpdateScrollX = scrollX;
     mLastStateUpdateScrollY = scrollY;
 
+    forceUpdateState();
+  }
+
+  private void updateStateOnScroll() {
+    updateStateOnScroll(getScrollX(), getScrollY());
+  }
+
+  private void updateScrollAwayState(int scrollAwayPaddingTop) {
+    if (mScrollAwayPaddingTop == scrollAwayPaddingTop) {
+      return;
+    }
+
+    mScrollAwayPaddingTop = scrollAwayPaddingTop;
+
+    forceUpdateState();
+  }
+
+  private void forceUpdateState() {
+    final int scrollX = mLastStateUpdateScrollX;
+    final int scrollY = mLastStateUpdateScrollY;
+    final int scrollAwayPaddingTop = mScrollAwayPaddingTop;
+
     mFabricViewStateManager.setState(
         new FabricViewStateManager.StateUpdateCallback() {
           @Override
           public WritableMap getStateUpdate() {
-
             WritableMap map = new WritableNativeMap();
             map.putDouble(CONTENT_OFFSET_LEFT, PixelUtil.toDIPFromPixel(scrollX));
             map.putDouble(CONTENT_OFFSET_TOP, PixelUtil.toDIPFromPixel(scrollY));
+            map.putDouble(SCROLL_AWAY_PADDING_TOP, PixelUtil.toDIPFromPixel(scrollAwayPaddingTop));
             return map;
           }
         });
   }
 
-  private void updateStateOnScroll() {
-    updateStateOnScroll(getScrollX(), getScrollY());
-  }
-
   @Override
   public FabricViewStateManager getFabricViewStateManager() {
     return mFabricViewStateManager;

ReactCommon/react/renderer/components/scrollview/ScrollViewShadowNode.cpp

@@ -34,7 +34,7 @@ void ScrollViewShadowNode::updateStateIfNeeded() {
 void ScrollViewShadowNode::updateScrollContentOffsetIfNeeded() {
 #ifndef ANDROID
   if (getLayoutMetrics().layoutDirection == LayoutDirection::RightToLeft) {
-    // Yoga place `contentView` on the right side of `scrollView` when RTL
+    // Yoga places `contentView` on the right side of `scrollView` when RTL
     // layout is enforced. To correct for this, in RTL setting, correct the
     // frame's origin. React Native Classic does this as well in
     // `RCTScrollContentShadowView.m`.
@@ -58,8 +58,9 @@ void ScrollViewShadowNode::layout(LayoutContext layoutContext) {
 }
 
 Point ScrollViewShadowNode::getContentOriginOffset() const {
-  auto contentOffset = getStateData().contentOffset;
-  return {-contentOffset.x, -contentOffset.y};
+  auto stateData = getStateData();
+  auto contentOffset = stateData.contentOffset;
+  return {-contentOffset.x, -contentOffset.y + stateData.scrollAwayPaddingTop};
 }
 
 } // namespace react

ReactCommon/react/renderer/components/scrollview/ScrollViewState.h

@@ -25,6 +25,7 @@ class ScrollViewState final {
  public:
   Point contentOffset;
   Rect contentBoundingRect;
+  int scrollAwayPaddingTop;
 
   /*
    * Returns size of scrollable area.
@@ -37,11 +38,13 @@ class ScrollViewState final {
       : contentOffset(
             {(Float)data["contentOffsetLeft"].getDouble(),
              (Float)data["contentOffsetTop"].getDouble()}),
-        contentBoundingRect({}){};
+        contentBoundingRect({}),
+        scrollAwayPaddingTop((Float)data["scrollAwayPaddingTop"].getDouble()){};
 
   folly::dynamic getDynamic() const {
     return folly::dynamic::object("contentOffsetLeft", contentOffset.x)(
-        "contentOffsetTop", contentOffset.y);
+        "contentOffsetTop", contentOffset.y)(
+        "scrollAwayPaddingTop", scrollAwayPaddingTop);
   };
   MapBuffer getMapBuffer() const {
     return MapBufferBuilder::EMPTY();

ReactCommon/react/renderer/core/tests/ConcreteShadowNodeTest.cpp

@@ -26,7 +26,7 @@ TEST(ConcreteShadowNodeTest, testSetStateData) {
 
   auto shadowNode = builder.build(element);
 
-  shadowNode->setStateData({{10, 11}, {{21, 22}, {301, 302}}});
+  shadowNode->setStateData({{10, 11}, {{21, 22}, {301, 302}}, 0});
 
   EXPECT_NE(
       shadowNode->getState(), shadowNode->getFamily().getMostRecentState());