Add pointerEvents prop to RN Android scroll views

Summary:
Per discussion in the previous diff D33672110, it's ok to add the `pointerEvents` prop to scrollview. This will help prevent scrolling on the ScrollView if pointerEvents is set to `box-none`, or `none`.

Corresponding doc changes are in facebook/react-native-website#2936

Changelog:
[Android][Added] - Add new API in ScrollView and HorizontalScrollView to process pointerEvents prop.

Reviewed By: javache

Differential Revision: D33699223

fbshipit-source-id: 1cae5113e9e7d988fc4c4765c41d817a321804c4

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

@@ -7,6 +7,8 @@
 
 package com.facebook.react.uimanager;
 
+import java.util.Locale;
+
 /**
  * Possible values for pointer events that a view and its descendants should receive. See
  * https://developer.mozilla.org/en-US/docs/Web/CSS/pointer-events for more info.
@@ -25,4 +27,16 @@ public enum PointerEvents {
   /** Container and all of its children receive touch events (like pointerEvents is unspecified). */
   AUTO,
   ;
+
+  public static PointerEvents parsePointerEvents(String pointerEventsStr) {
+    return PointerEvents.valueOf(pointerEventsStr.toUpperCase(Locale.US).replace("-", "_"));
+  }
+
+  public static boolean canBeTouchTarget(PointerEvents pointerEvents) {
+    return pointerEvents == AUTO || pointerEvents == PointerEvents.BOX_ONLY;
+  }
+
+  public static boolean canChildrenBeTouchTarget(PointerEvents pointerEvents) {
+    return pointerEvents == PointerEvents.AUTO || pointerEvents == PointerEvents.BOX_NONE;
+  }
 }

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

@@ -40,6 +40,7 @@
 import com.facebook.react.modules.i18nmanager.I18nUtil;
 import com.facebook.react.uimanager.FabricViewStateManager;
 import com.facebook.react.uimanager.MeasureSpecAssertions;
+import com.facebook.react.uimanager.PointerEvents;
 import com.facebook.react.uimanager.ReactClippingViewGroup;
 import com.facebook.react.uimanager.ReactClippingViewGroupHelper;
 import com.facebook.react.uimanager.ReactOverflowViewWithInset;
@@ -105,6 +106,7 @@ public class ReactHorizontalScrollView extends HorizontalScrollView
   private final FabricViewStateManager mFabricViewStateManager = new FabricViewStateManager();
   private final ReactScrollViewScrollState mReactScrollViewScrollState;
   private final ValueAnimator DEFAULT_FLING_ANIMATOR = ObjectAnimator.ofInt(this, "scrollX", 0, 0);
+  private PointerEvents mPointerEvents = PointerEvents.AUTO;
 
   private final Rect mTempRect = new Rect();
 
@@ -452,6 +454,11 @@ public boolean onInterceptTouchEvent(MotionEvent ev) {
       return false;
     }
 
+    // We intercept the touch event if the children are not supposed to receive it.
+    if (!PointerEvents.canChildrenBeTouchTarget(mPointerEvents)) {
+      return true;
+    }
+
     try {
       if (super.onInterceptTouchEvent(ev)) {
         NativeGestureUtil.notifyNativeGestureStarted(this, ev);
@@ -519,6 +526,11 @@ public boolean onTouchEvent(MotionEvent ev) {
       return false;
     }
 
+    // We do not accept the touch event if this view is not supposed to receive it.
+    if (!PointerEvents.canBeTouchTarget(mPointerEvents)) {
+      return false;
+    }
+
     mVelocityHelper.calculateVelocity(ev);
     int action = ev.getAction() & MotionEvent.ACTION_MASK;
     if (action == MotionEvent.ACTION_UP && mDragging) {
@@ -1253,4 +1265,12 @@ public int getFlingExtrapolatedDistance(int velocityX) {
             this, velocityX, 0, Math.max(0, computeHorizontalScrollRange() - getWidth()), 0)
         .x;
   }
+
+  public void setPointerEvents(PointerEvents pointerEvents) {
+    mPointerEvents = pointerEvents;
+  }
+
+  public PointerEvents getPointerEvents() {
+    return mPointerEvents;
+  }
 }

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

@@ -16,6 +16,7 @@
 import com.facebook.react.module.annotations.ReactModule;
 import com.facebook.react.uimanager.DisplayMetricsHolder;
 import com.facebook.react.uimanager.PixelUtil;
+import com.facebook.react.uimanager.PointerEvents;
 import com.facebook.react.uimanager.ReactClippingViewGroupHelper;
 import com.facebook.react.uimanager.ReactStylesDiffMap;
 import com.facebook.react.uimanager.Spacing;
@@ -321,4 +322,13 @@ public void setContentOffset(ReactHorizontalScrollView view, ReadableMap value)
       view.scrollTo(0, 0);
     }
   }
+
+  @ReactProp(name = ViewProps.POINTER_EVENTS)
+  public void setPointerEvents(ReactHorizontalScrollView view, @Nullable String pointerEventsStr) {
+    if (pointerEventsStr == null) {
+      view.setPointerEvents(PointerEvents.AUTO);
+    } else {
+      view.setPointerEvents(PointerEvents.parsePointerEvents(pointerEventsStr));
+    }
+  }
 }

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

@@ -36,6 +36,7 @@
 import com.facebook.react.common.ReactConstants;
 import com.facebook.react.uimanager.FabricViewStateManager;
 import com.facebook.react.uimanager.MeasureSpecAssertions;
+import com.facebook.react.uimanager.PointerEvents;
 import com.facebook.react.uimanager.ReactClippingViewGroup;
 import com.facebook.react.uimanager.ReactClippingViewGroupHelper;
 import com.facebook.react.uimanager.ReactOverflowViewWithInset;
@@ -102,6 +103,7 @@ public class ReactScrollView extends ScrollView
   private final ReactScrollViewScrollState mReactScrollViewScrollState =
       new ReactScrollViewScrollState(ViewCompat.LAYOUT_DIRECTION_LTR);
   private final ValueAnimator DEFAULT_FLING_ANIMATOR = ObjectAnimator.ofInt(this, "scrollY", 0, 0);
+  private PointerEvents mPointerEvents = PointerEvents.AUTO;
 
   public ReactScrollView(Context context) {
     this(context, null);
@@ -332,6 +334,11 @@ public boolean onInterceptTouchEvent(MotionEvent ev) {
       return false;
     }
 
+    // We intercept the touch event if the children are not supposed to receive it.
+    if (!PointerEvents.canChildrenBeTouchTarget(mPointerEvents)) {
+      return true;
+    }
+
     try {
       if (super.onInterceptTouchEvent(ev)) {
         NativeGestureUtil.notifyNativeGestureStarted(this, ev);
@@ -357,6 +364,11 @@ public boolean onTouchEvent(MotionEvent ev) {
       return false;
     }
 
+    // We do not accept the touch event if this view is not supposed to receive it.
+    if (!PointerEvents.canBeTouchTarget(mPointerEvents)) {
+      return false;
+    }
+
     mVelocityHelper.calculateVelocity(ev);
     int action = ev.getAction() & MotionEvent.ACTION_MASK;
     if (action == MotionEvent.ACTION_UP && mDragging) {
@@ -1115,4 +1127,12 @@ public int getFlingExtrapolatedDistance(int velocityY) {
     return ReactScrollViewHelper.predictFinalScrollPosition(this, 0, velocityY, 0, getMaxScrollY())
         .y;
   }
+
+  public void setPointerEvents(PointerEvents pointerEvents) {
+    mPointerEvents = pointerEvents;
+  }
+
+  public PointerEvents getPointerEvents() {
+    return mPointerEvents;
+  }
 }

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

@@ -19,6 +19,7 @@
 import com.facebook.react.module.annotations.ReactModule;
 import com.facebook.react.uimanager.DisplayMetricsHolder;
 import com.facebook.react.uimanager.PixelUtil;
+import com.facebook.react.uimanager.PointerEvents;
 import com.facebook.react.uimanager.ReactClippingViewGroupHelper;
 import com.facebook.react.uimanager.ReactStylesDiffMap;
 import com.facebook.react.uimanager.Spacing;
@@ -363,4 +364,13 @@ public static Map<String, Object> createExportedCustomDirectEventTypeConstants()
             MapBuilder.of("registrationName", "onMomentumScrollEnd"))
         .build();
   }
+
+  @ReactProp(name = ViewProps.POINTER_EVENTS)
+  public void setPointerEvents(ReactScrollView view, @Nullable String pointerEventsStr) {
+    if (pointerEventsStr == null) {
+      view.setPointerEvents(PointerEvents.AUTO);
+    } else {
+      view.setPointerEvents(PointerEvents.parsePointerEvents(pointerEventsStr));
+    }
+  }
 }