Fabric: Support of accessibility events for <View> component

Summary: This also illustrates how we should use EventHandlers objects.

Reviewed By: fkgozali

Differential Revision: D8053357

fbshipit-source-id: cba084c8a871e40c7536720fce290c3467d33061

React/Fabric/Mounting/ComponentViews/View/RCTViewComponentView.h

@@ -9,8 +9,10 @@
 
 #import <React/RCTComponentViewProtocol.h>
 #import <React/UIView+ComponentViewProtocol.h>
+#import <fabric/core/EventHandlers.h>
 #import <fabric/core/LayoutMetrics.h>
 #import <fabric/core/Props.h>
+#import <fabric/view/ViewEventHandlers.h>
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -21,6 +23,7 @@ NS_ASSUME_NONNULL_BEGIN
 @protected
   facebook::react::LayoutMetrics _layoutMetrics;
   facebook::react::SharedProps _props;
+  facebook::react::SharedViewEventHandlers _eventHandlers;
 }
 
 @end

React/Fabric/Mounting/ComponentViews/View/RCTViewComponentView.mm

@@ -8,13 +8,15 @@
 #import "RCTViewComponentView.h"
 
 #import <fabric/view/ViewProps.h>
+#import <fabric/view/ViewEventHandlers.h>
+
 
 using namespace facebook::react;
 
 @implementation RCTViewComponentView
 
-- (void)updateProps:(facebook::react::SharedProps)props
-           oldProps:(facebook::react::SharedProps)oldProps
+- (void)updateProps:(SharedProps)props
+           oldProps:(SharedProps)oldProps
 {
   if (!oldProps) {
     oldProps = _props ?: std::make_shared<ViewProps>();
@@ -31,6 +33,12 @@ using namespace facebook::react;
   // TODO: Implement all sutable non-layout <View> props.
 }
 
+- (void)updateEventHandlers:(SharedEventHandlers)eventHandlers
+{
+  assert(std::dynamic_pointer_cast<const ViewEventHandlers>(eventHandlers));
+  _eventHandlers = std::static_pointer_cast<const ViewEventHandlers>(eventHandlers);
+}
+
 - (void)updateLayoutMetrics:(LayoutMetrics)layoutMetrics
            oldLayoutMetrics:(LayoutMetrics)oldLayoutMetrics
 {
@@ -39,4 +47,24 @@ using namespace facebook::react;
   _layoutMetrics = layoutMetrics;
 }
 
+#pragma mark - Accessibility Events
+
+- (BOOL)accessibilityActivate
+{
+  _eventHandlers->onAccessibilityTap();
+  return YES;
+}
+
+- (BOOL)accessibilityPerformMagicTap
+{
+  _eventHandlers->onAccessibilityMagicTap();
+  return YES;
+}
+
+- (BOOL)didActivateAccessibilityCustomAction:(UIAccessibilityCustomAction *)action
+{
+  _eventHandlers->onAccessibilityAction([action.name cStringUsingEncoding:NSASCIIStringEncoding]);
+  return YES;
+}
+
 @end

ReactCommon/fabric/text/paragraph/ParagraphComponentDescriptor.h

@@ -17,11 +17,13 @@ namespace react {
 /*
  * Descriptor for <Paragraph> component.
  */
-class ParagraphComponentDescriptor: public ConcreteComponentDescriptor<ParagraphShadowNode> {
+class ParagraphComponentDescriptor final:
+  public ConcreteComponentDescriptor<ParagraphShadowNode> {
+
 public:
 
-  ParagraphComponentDescriptor():
-    ConcreteComponentDescriptor<ParagraphShadowNode>() {
+  ParagraphComponentDescriptor(SharedEventDispatcher eventDispatcher):
+    ConcreteComponentDescriptor<ParagraphShadowNode>(eventDispatcher) {
     // Every single `ParagraphShadowNode` will have a reference to
     // a shared `TextLayoutManager`.
     textLayoutManager_ = std::make_shared<TextLayoutManager>();

ReactCommon/fabric/view/ConcreteViewShadowNode.h

@@ -12,6 +12,7 @@
 #include <fabric/core/ShadowNode.h>
 #include <fabric/debug/DebugStringConvertibleItem.h>
 #include <fabric/view/AccessibleShadowNode.h>
+#include <fabric/view/ViewEventHandlers.h>
 #include <fabric/view/ViewProps.h>
 #include <fabric/view/YogaLayoutableShadowNode.h>
 
@@ -23,9 +24,9 @@ namespace react {
  * as <View> and similar basic behaviour).
  * For example: <Paragraph>, <Image>, but not <Text>, <RawText>.
  */
-template <typename ViewPropsT>
+template <typename ViewPropsT = ViewProps, typename ViewEventHandlersT = ViewEventHandlers>
 class ConcreteViewShadowNode:
-  public ConcreteShadowNode<ViewPropsT>,
+  public ConcreteShadowNode<ViewPropsT, ViewEventHandlersT>,
   public AccessibleShadowNode,
   public YogaLayoutableShadowNode {
 
@@ -37,21 +38,23 @@ public:
 
   using ConcreteViewProps = ViewPropsT;
   using SharedConcreteViewProps = std::shared_ptr<const ViewPropsT>;
+  using ConcreteViewEventHandlers = ViewEventHandlersT;
+  using SharedConcreteViewEventHandlers = std::shared_ptr<const ViewEventHandlersT>;
   using SharedConcreteViewShadowNode = std::shared_ptr<const ConcreteViewShadowNode>;
 
   ConcreteViewShadowNode(
     const Tag &tag,
     const Tag &rootTag,
-    const InstanceHandle &instanceHandle,
     const SharedConcreteViewProps &props,
+    const SharedConcreteViewEventHandlers &eventHandlers,
     const SharedShadowNodeSharedList &children,
     const ShadowNodeCloneFunction &cloneFunction
   ):
-    ConcreteShadowNode<ViewPropsT>(
+    ConcreteShadowNode<ViewPropsT, ViewEventHandlersT>(
       tag,
       rootTag,
-      instanceHandle,
       props,
+      eventHandlers,
       children,
       cloneFunction
     ),
@@ -66,11 +69,13 @@ public:
   ConcreteViewShadowNode(
     const SharedConcreteViewShadowNode &shadowNode,
     const SharedConcreteViewProps &props,
+    const SharedConcreteViewEventHandlers &eventHandlers,
     const SharedShadowNodeSharedList &children
   ):
-    ConcreteShadowNode<ViewPropsT>(
+    ConcreteShadowNode<ViewPropsT, ViewEventHandlersT>(
       shadowNode,
       props,
+      eventHandlers,
       children
     ),
     AccessibleShadowNode(

ReactCommon/fabric/view/ViewEventHandlers.cpp

@@ -0,0 +1,28 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include "ViewEventHandlers.h"
+
+namespace facebook {
+namespace react {
+
+#pragma mark - Accessibility
+
+void ViewEventHandlers::onAccessibilityAction(const std::string &name) const {
+  dispatchEvent("accessibilityAction", folly::dynamic::object("action", name));
+}
+
+void ViewEventHandlers::onAccessibilityTap() const {
+  dispatchEvent("accessibilityTap");
+}
+
+void ViewEventHandlers::onAccessibilityMagicTap() const {
+  dispatchEvent("magicTap");
+}
+
+} // namespace react
+} // namespace facebook

ReactCommon/fabric/view/ViewEventHandlers.h

@@ -0,0 +1,33 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+#pragma once
+
+#include <memory>
+
+#include <fabric/core/EventHandlers.h>
+
+namespace facebook {
+namespace react {
+
+class ViewEventHandlers;
+
+using SharedViewEventHandlers = std::shared_ptr<const ViewEventHandlers>;
+
+class ViewEventHandlers:
+  public EventHandlers {
+
+public:
+
+  using EventHandlers::EventHandlers;
+
+  void onAccessibilityAction(const std::string &name) const;
+  void onAccessibilityTap() const;
+  void onAccessibilityMagicTap() const;
+};
+
+} // namespace react
+} // namespace facebook

ReactCommon/fabric/view/ViewShadowNode.h

@@ -20,7 +20,7 @@ class ViewShadowNode;
 using SharedViewShadowNode = std::shared_ptr<const ViewShadowNode>;
 
 class ViewShadowNode final:
-  public ConcreteViewShadowNode<ViewProps> {
+  public ConcreteViewShadowNode<ViewProps, ViewEventHandlers> {
 
 public:
 

ReactCommon/fabric/view/accessibility/AccessibilityProps.h

@@ -35,9 +35,6 @@ public:
   const AccessibilityTraits accessibilityTraits {AccessibilityTraits::None};
   const bool accessibilityViewIsModal {false};
   const bool accessibilityElementsHidden {false};
-  const SharedDirectEventHandler onAccessibilityAction {nullptr};
-  const SharedDirectEventHandler onAccessibilityTap {nullptr};
-  const SharedDirectEventHandler onMagicTap {nullptr};
 };
 
 } // namespace react