TalkBack support for ScrollView accessibility announcements (list and grid) (facebook#33180)

Summary:
This issue fixes [30977][17] . The Pull Request was previously published by [intergalacticspacehighway][13] with [31666][19].
The solution consists of:
1. Adding Javascript logic in the [FlatList][14], SectionList, VirtualizedList components to provide accessibility information (row and column position) for each cell in the method [renderItem][20] as a fourth parameter [accessibilityCollectionItem][21]. The information is saved on the native side in the AccessibilityNodeInfo and announced by TalkBack when changing row, column, or page ([video example][12]). The prop accessibilityCollectionItem is available in the View component which wraps each FlatList cell.
2. Adding Java logic in [ReactScrollView.java][16] and HorizontalScrollView to announce pages with TalkBack when scrolling up/down. The missing AOSP logic in [ScrollView.java][10] (see also the [GridView][11] example) is responsible for announcing Page Scrolling with TalkBack.

Relevant Links:
x [Additional notes on this PR][18]
x [discussion on the additional container View around each FlatList cell][22]
x [commit adding prop getCellsInItemCount to VirtualizedList][23]

## Changelog

[Android] [Added] - Accessibility announcement for list and grid in FlatList

Pull Request resolved: facebook#33180

Test Plan:
[1]. TalkBack announces pages and cells with Horizontal Flatlist in the Paper Renderer ([link][1])
[2]. TalkBack announces pages and cells with Vertical Flatlist in the Paper Renderer ([link][2])
[3]. `FlatList numColumns={undefined}` Should not trigger Runtime Error NoSuchKey exception columnCount when enabling TalkBack. ([link][3])
[4]. TalkBack announces pages and cells with Nested Horizontal Flatlist in the rn-tester app ([link][4])

[1]: fabOnReact/react-native-notes#6 (comment)
[2]: fabOnReact/react-native-notes#6 (comment)
[3]: fabOnReact/react-native-notes#6 (comment)
[4]: fabOnReact/react-native-notes#6 (comment)
[10]:https://github.com/aosp-mirror/platform_frameworks_base/blob/1ac46f932ef88a8f96d652580d8105e361ffc842/core/java/android/widget/AdapterView.java#L1027-L1029 "GridView.java method responsible for calling setFromIndex and setToIndex"
[11]:fabOnReact/react-native-notes#6 (comment) "test case on Android GridView"
[12]:fabOnReact/react-native-notes#6 (comment) "TalkBack announces pages and cells with Horizontal Flatlist in the Paper Renderer"
[13]:https://github.com/intergalacticspacehighway "github intergalacticspacehighway"
[14]:https://github.com/fabriziobertoglio1987/react-native/blob/80acf523a4410adac8005d5c9472fb87f78e12ee/Libraries/Lists/FlatList.js#L617-L636 "FlatList accessibilityCollectionItem"
[16]:https://github.com/fabriziobertoglio1987/react-native/blob/5706bd7d3ee35dca48f85322a2bdcaec0bce2c85/ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactScrollView.java#L183-L184 "logic added to ReactScrollView.java"
[17]: facebook#30977
[18]: fabOnReact/react-native-notes#6
[19]: facebook#31666
[20]: https://reactnative.dev/docs/next/flatlist#required-renderitem "FlatList renderItem documentation"
[21]: 7514735 "commit that introduces fourth param accessibilityCollectionItem in callback renderItem"
[22]: facebook#33180 (comment) "discussion on the additional container View around each FlatList cell"
[23]: d50fd1a "commit adding prop getCellsInItemCount to VirtualizedList"

Reviewed By: kacieb

Differential Revision: D34518929

Pulled By: blavalla

fbshipit-source-id: 410a05263a56162bf505a4cad957b24005ed65ed

Author: fabOnReact

Libraries/Components/View/ViewAccessibility.js

@@ -43,6 +43,7 @@ export type AccessibilityRole =
   | 'tablist'
   | 'timer'
   | 'list'
+  | 'grid'
   | 'toolbar';
 
 // the info associated with an accessibility action

Libraries/Components/View/ViewPropTypes.js

@@ -464,6 +464,23 @@ export type ViewProps = $ReadOnly<{|
    */
   accessibilityActions?: ?$ReadOnlyArray<AccessibilityActionInfo>,
 
+  /**
+   *
+   * Node Information of a FlatList, VirtualizedList or SectionList collection item.
+   * A collection item starts at a given row and column in the collection, and spans one or more rows and columns.
+   *
+   * @platform android
+   *
+   */
+  accessibilityCollectionItem?: ?{
+    rowIndex: number,
+    rowSpan: number,
+    columnIndex: number,
+    columnSpan: number,
+    heading: boolean,
+    itemIndex: number,
+  },
+
   /**
    * Specifies the nativeID of the associated label text. When the assistive technology focuses on the component with this props, the text is read aloud.
    *

Libraries/Lists/FlatList.js

@@ -624,10 +624,17 @@ class FlatList<ItemT> extends React.PureComponent<Props<ItemT>, void> {
           return (
             <View style={StyleSheet.compose(styles.row, columnWrapperStyle)}>
               {item.map((it, kk) => {
+                const itemIndex = index * cols + kk;
+                const accessibilityCollectionItem = {
+                  ...info.accessibilityCollectionItem,
+                  columnIndex: itemIndex % cols,
+                  itemIndex: itemIndex,
+                };
                 const element = renderer({
                   item: it,
-                  index: index * cols + kk,
+                  index: itemIndex,
                   separators: info.separators,
+                  accessibilityCollectionItem,
                 });
                 return element != null ? (
                   <React.Fragment key={kk}>{element}</React.Fragment>
@@ -658,6 +665,7 @@ class FlatList<ItemT> extends React.PureComponent<Props<ItemT>, void> {
     return (
       <VirtualizedList
         {...restProps}
+        numColumns={numColumns}
         getItem={this._getItem}
         getItemCount={this._getItemCount}
         keyExtractor={this._keyExtractor}

Libraries/Lists/VirtualizedList.js

@@ -12,6 +12,7 @@ const Batchinator = require('../Interaction/Batchinator');
 const FillRateHelper = require('./FillRateHelper');
 const ReactNative = require('../Renderer/shims/ReactNative');
 const RefreshControl = require('../Components/RefreshControl/RefreshControl');
+const Platform = require('../Utilities/Platform');
 const ScrollView = require('../Components/ScrollView/ScrollView');
 const StyleSheet = require('../StyleSheet/StyleSheet');
 const View = require('../Components/View/View');
@@ -52,10 +53,20 @@ export type Separators = {
   ...
 };
 
+export type AccessibilityCollectionItem = {
+  itemIndex: number,
+  rowIndex: number,
+  rowSpan: number,
+  columnIndex: number,
+  columnSpan: number,
+  heading: boolean,
+};
+
 export type RenderItemProps<ItemT> = {
   item: ItemT,
   index: number,
   separators: Separators,
+  accessibilityCollectionItem: AccessibilityCollectionItem,
   ...
 };
 
@@ -84,9 +95,19 @@ type RequiredProps = {|
    */
   getItem: (data: any, index: number) => ?Item,
   /**
-   * Determines how many items are in the data blob.
+   * Determines how many items (rows) are in the data blob.
    */
   getItemCount: (data: any) => number,
+  /**
+   * Determines how many cells are in the data blob
+   * see https://bit.ly/35RKX7H
+   */
+  getCellsInItemCount?: (data: any) => number,
+  /**
+   * The number of columns used in FlatList.
+   * The default of 1 is used in other components to calculate the accessibilityCollection prop.
+   */
+  numColumns?: ?number,
 |};
 type OptionalProps = {|
   renderItem?: ?RenderItemType<Item>,
@@ -306,6 +327,10 @@ type Props = {|
   ...OptionalProps,
 |};
 
+function numColumnsOrDefault(numColumns: ?number) {
+  return numColumns ?? 1;
+}
+
 let _usedIndexForKey = false;
 let _keylessItemComponentName: string = '';
 
@@ -1242,8 +1267,33 @@ class VirtualizedList extends React.PureComponent<Props, State> {
     );
   }
 
+  _getCellsInItemCount = props => {
+    const {getCellsInItemCount, data} = props;
+    if (getCellsInItemCount) {
+      return getCellsInItemCount(data);
+    }
+    if (Array.isArray(data)) {
+      return data.length;
+    }
+    return 0;
+  };
+
   _defaultRenderScrollComponent = props => {
+    const {getItemCount, data} = props;
     const onRefresh = props.onRefresh;
+    const numColumns = numColumnsOrDefault(props.numColumns);
+    const accessibilityRole = Platform.select({
+      android: numColumns > 1 ? 'grid' : 'list',
+    });
+    const rowCount = getItemCount(data);
+    const accessibilityCollection = {
+      // over-ride _getCellsInItemCount to handle Objects or other data formats
+      // see https://bit.ly/35RKX7H
+      itemCount: this._getCellsInItemCount(props),
+      rowCount,
+      columnCount: numColumns,
+      hierarchical: false,
+    };
     if (this._isNestedWithSameOrientation()) {
       // $FlowFixMe[prop-missing] - Typing ReactNativeComponent revealed errors
       return <View {...props} />;
@@ -1258,6 +1308,8 @@ class VirtualizedList extends React.PureComponent<Props, State> {
         // $FlowFixMe[prop-missing] Invalid prop usage
         <ScrollView
           {...props}
+          accessibilityRole={accessibilityRole}
+          accessibilityCollection={accessibilityCollection}
           refreshControl={
             props.refreshControl == null ? (
               <RefreshControl
@@ -1272,8 +1324,14 @@ class VirtualizedList extends React.PureComponent<Props, State> {
         />
       );
     } else {
-      // $FlowFixMe[prop-missing] Invalid prop usage
-      return <ScrollView {...props} />;
+      return (
+        // $FlowFixMe[prop-missing] Invalid prop usage
+        <ScrollView
+          {...props}
+          accessibilityRole={accessibilityRole}
+          accessibilityCollection={accessibilityCollection}
+        />
+      );
     }
   };
 
@@ -2018,10 +2076,19 @@ class CellRenderer extends React.Component<
     }
 
     if (renderItem) {
+      const accessibilityCollectionItem = {
+        itemIndex: index,
+        rowIndex: index,
+        rowSpan: 1,
+        columnIndex: 0,
+        columnSpan: 1,
+        heading: false,
+      };
       return renderItem({
         item,
         index,
         separators: this._separators,
+        accessibilityCollectionItem,
       });
     }
 

Libraries/Lists/VirtualizedSectionList.js

@@ -10,6 +10,7 @@
 
 import invariant from 'invariant';
 import type {ViewToken} from './ViewabilityHelper';
+import type {AccessibilityCollectionItem} from './VirtualizedList';
 import {keyExtractor as defaultKeyExtractor} from './VirtualizeUtils';
 import {View, VirtualizedList} from 'react-native';
 import * as React from 'react';
@@ -338,7 +339,16 @@ class VirtualizedSectionList<
 
   _renderItem =
     (listItemCount: number) =>
-    ({item, index}: {item: Item, index: number, ...}) => {
+    ({
+      item,
+      index,
+      accessibilityCollectionItem,
+    }: {
+      item: Item,
+      index: number,
+      accessibilityCollectionItem: AccessibilityCollectionItem,
+      ...
+    }) => {
       const info = this._subExtractor(index);
       if (!info) {
         return null;
@@ -367,6 +377,7 @@ class VirtualizedSectionList<
             LeadingSeparatorComponent={
               infoIndex === 0 ? this.props.SectionSeparatorComponent : undefined
             }
+            accessibilityCollectionItem={accessibilityCollectionItem}
             cellKey={info.key}
             index={infoIndex}
             item={item}
@@ -479,6 +490,7 @@ type ItemWithSeparatorProps = $ReadOnly<{|
   updatePropsFor: (prevCellKey: string, value: Object) => void,
   renderItem: Function,
   inverted: boolean,
+  accessibilityCollectionItem: AccessibilityCollectionItem,
 |}>;
 
 function ItemWithSeparator(props: ItemWithSeparatorProps): React.Node {
@@ -496,6 +508,7 @@ function ItemWithSeparator(props: ItemWithSeparatorProps): React.Node {
     index,
     section,
     inverted,
+    accessibilityCollectionItem,
   } = props;
 
   const [leadingSeparatorHiglighted, setLeadingSeparatorHighlighted] =
@@ -569,6 +582,7 @@ function ItemWithSeparator(props: ItemWithSeparatorProps): React.Node {
     index,
     section,
     separators,
+    accessibilityCollectionItem,
   });
   const leadingSeparator = LeadingSeparatorComponent != null && (
     <LeadingSeparatorComponent

Libraries/Lists/__tests__/__snapshots__/FlatList-test.js.snap

@@ -6,6 +6,14 @@ exports[`FlatList renders all the bells and whistles 1`] = `
   ListEmptyComponent={[Function]}
   ListFooterComponent={[Function]}
   ListHeaderComponent={[Function]}
+  accessibilityCollection={
+    Object {
+      "columnCount": 2,
+      "hierarchical": false,
+      "itemCount": 5,
+      "rowCount": 3,
+    }
+  }
   data={
     Array [
       Object {
@@ -29,6 +37,7 @@ exports[`FlatList renders all the bells and whistles 1`] = `
   getItemCount={[Function]}
   getItemLayout={[Function]}
   keyExtractor={[Function]}
+  numColumns={2}
   onContentSizeChange={[Function]}
   onLayout={[Function]}
   onMomentumScrollBegin={[Function]}
@@ -121,6 +130,14 @@ exports[`FlatList renders all the bells and whistles 1`] = `
 
 exports[`FlatList renders empty list 1`] = `
 <RCTScrollView
+  accessibilityCollection={
+    Object {
+      "columnCount": 1,
+      "hierarchical": false,
+      "itemCount": 0,
+      "rowCount": 0,
+    }
+  }
   data={Array []}
   getItem={[Function]}
   getItemCount={[Function]}
@@ -144,6 +161,14 @@ exports[`FlatList renders empty list 1`] = `
 
 exports[`FlatList renders null list 1`] = `
 <RCTScrollView
+  accessibilityCollection={
+    Object {
+      "columnCount": 1,
+      "hierarchical": false,
+      "itemCount": 0,
+      "rowCount": 0,
+    }
+  }
   getItem={[Function]}
   getItemCount={[Function]}
   keyExtractor={[Function]}
@@ -166,6 +191,14 @@ exports[`FlatList renders null list 1`] = `
 
 exports[`FlatList renders simple list (multiple columns) 1`] = `
 <RCTScrollView
+  accessibilityCollection={
+    Object {
+      "columnCount": 2,
+      "hierarchical": false,
+      "itemCount": 3,
+      "rowCount": 2,
+    }
+  }
   data={
     Array [
       Object {
@@ -182,6 +215,7 @@ exports[`FlatList renders simple list (multiple columns) 1`] = `
   getItem={[Function]}
   getItemCount={[Function]}
   keyExtractor={[Function]}
+  numColumns={2}
   onContentSizeChange={[Function]}
   onLayout={[Function]}
   onMomentumScrollBegin={[Function]}
@@ -237,6 +271,14 @@ exports[`FlatList renders simple list (multiple columns) 1`] = `
 
 exports[`FlatList renders simple list 1`] = `
 <RCTScrollView
+  accessibilityCollection={
+    Object {
+      "columnCount": 1,
+      "hierarchical": false,
+      "itemCount": 3,
+      "rowCount": 3,
+    }
+  }
   data={
     Array [
       Object {
@@ -298,6 +340,14 @@ exports[`FlatList renders simple list 1`] = `
 exports[`FlatList renders simple list using ListItemComponent (multiple columns) 1`] = `
 <RCTScrollView
   ListItemComponent={[Function]}
+  accessibilityCollection={
+    Object {
+      "columnCount": 2,
+      "hierarchical": false,
+      "itemCount": 3,
+      "rowCount": 2,
+    }
+  }
   data={
     Array [
       Object {
@@ -314,6 +364,7 @@ exports[`FlatList renders simple list using ListItemComponent (multiple columns)
   getItem={[Function]}
   getItemCount={[Function]}
   keyExtractor={[Function]}
+  numColumns={2}
   onContentSizeChange={[Function]}
   onLayout={[Function]}
   onMomentumScrollBegin={[Function]}
@@ -369,6 +420,14 @@ exports[`FlatList renders simple list using ListItemComponent (multiple columns)
 exports[`FlatList renders simple list using ListItemComponent 1`] = `
 <RCTScrollView
   ListItemComponent={[Function]}
+  accessibilityCollection={
+    Object {
+      "columnCount": 1,
+      "hierarchical": false,
+      "itemCount": 3,
+      "rowCount": 3,
+    }
+  }
   data={
     Array [
       Object {