xplat/js/react-native-github/packages/react-native/ReactAndroid/src/m…

…ain/java/com/facebook/react/views/scroll/ReactScrollViewAccessibilityDelegate.java (facebook#48530)

Summary:
Pull Request resolved: facebook#48530

Changelog: [Internal]

Reviewed By: tdn120

Differential Revision: D67912326

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactScrollViewAccessibilityDelegate.kt

@@ -0,0 +1,136 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.facebook.react.views.scroll
+
+import android.view.View
+import android.view.ViewGroup
+import android.view.accessibility.AccessibilityEvent
+import androidx.core.view.AccessibilityDelegateCompat
+import androidx.core.view.accessibility.AccessibilityNodeInfoCompat
+import com.facebook.react.R
+import com.facebook.react.bridge.AssertionException
+import com.facebook.react.bridge.ReactSoftExceptionLogger
+import com.facebook.react.bridge.ReadableMap
+import com.facebook.react.uimanager.ReactAccessibilityDelegate
+import com.facebook.react.uimanager.ReactAccessibilityDelegate.AccessibilityRole
+
+internal class ReactScrollViewAccessibilityDelegate : AccessibilityDelegateCompat() {
+
+  private val TAG: String = ReactScrollViewAccessibilityDelegate::class.java.simpleName
+
+  override fun onInitializeAccessibilityEvent(host: View, event: AccessibilityEvent) {
+    super.onInitializeAccessibilityEvent(host, event)
+    if (host is ReactScrollView || host is ReactHorizontalScrollView) {
+      onInitializeAccessibilityEventInternal(host, event)
+    } else {
+      ReactSoftExceptionLogger.logSoftException(
+          TAG,
+          AssertionException(
+              "ReactScrollViewAccessibilityDelegate should only be used with ReactScrollView or ReactHorizontalScrollView, not with class: ${host.javaClass.simpleName}"))
+    }
+  }
+
+  override fun onInitializeAccessibilityNodeInfo(host: View, info: AccessibilityNodeInfoCompat) {
+    super.onInitializeAccessibilityNodeInfo(host, info)
+    if (host is ReactScrollView || host is ReactHorizontalScrollView) {
+      onInitializeAccessibilityNodeInfoInternal(host, info)
+    } else {
+      ReactSoftExceptionLogger.logSoftException(
+          TAG,
+          AssertionException(
+              "ReactScrollViewAccessibilityDelegate should only be used with ReactScrollView or ReactHorizontalScrollView, not with class: ${host.javaClass.simpleName}"))
+    }
+  }
+
+  private fun onInitializeAccessibilityEventInternal(view: View, event: AccessibilityEvent) {
+    val accessibilityCollection =
+        view.getTag(R.id.accessibility_collection) as? ReadableMap ?: return
+
+    event.itemCount = accessibilityCollection.getInt("itemCount")
+
+    val contentView = (view as? ViewGroup)?.getChildAt(0) as? ViewGroup ?: return
+
+    var firstVisibleIndex: Int? = null
+    var lastVisibleIndex: Int? = null
+
+    for (index in 0..<contentView.childCount) {
+      val nextChild = contentView.getChildAt(index)
+      val isVisible: Boolean =
+          if (view is ReactScrollView) {
+            view.isPartiallyScrolledInView(nextChild)
+          } else if (view is ReactHorizontalScrollView) {
+            view.isPartiallyScrolledInView(nextChild)
+          } else {
+            return
+          }
+      var accessibilityCollectionItem: ReadableMap? =
+          nextChild.getTag(R.id.accessibility_collection_item) as ReadableMap
+
+      if (nextChild !is ViewGroup) {
+        return
+      }
+
+      // If this child's accessibilityCollectionItem is null, we'll check one more
+      // nested child.
+      // Happens when getItemLayout is not passed in FlatList which adds an additional
+      // View in the hierarchy.
+      if (nextChild.childCount > 0 && accessibilityCollectionItem == null) {
+        val nestedNextChild = nextChild.getChildAt(0)
+        if (nestedNextChild != null) {
+          val nestedChildAccessibility =
+              nestedNextChild.getTag(R.id.accessibility_collection_item) as? ReadableMap
+          if (nestedChildAccessibility != null) {
+            accessibilityCollectionItem = nestedChildAccessibility
+          }
+        }
+      }
+
+      if (isVisible && accessibilityCollectionItem != null) {
+        if (firstVisibleIndex == null) {
+          firstVisibleIndex = accessibilityCollectionItem.getInt("itemIndex")
+        }
+        lastVisibleIndex = accessibilityCollectionItem.getInt("itemIndex")
+      }
+
+      if (firstVisibleIndex != null && lastVisibleIndex != null) {
+        event.fromIndex = firstVisibleIndex
+        event.toIndex = lastVisibleIndex
+      }
+    }
+  }
+
+  private fun onInitializeAccessibilityNodeInfoInternal(
+      view: View,
+      info: AccessibilityNodeInfoCompat
+  ) {
+    val accessibilityRole = AccessibilityRole.fromViewTag(view)
+
+    if (accessibilityRole != null) {
+      ReactAccessibilityDelegate.setRole(info, accessibilityRole, view.context)
+    }
+
+    val accessibilityCollection = view.getTag(R.id.accessibility_collection) as? ReadableMap
+
+    if (accessibilityCollection != null) {
+      val rowCount = accessibilityCollection.getInt("rowCount")
+      val columnCount = accessibilityCollection.getInt("columnCount")
+      val hierarchical = accessibilityCollection.getBoolean("hierarchical")
+
+      val collectionInfoCompat =
+          AccessibilityNodeInfoCompat.CollectionInfoCompat.obtain(
+              rowCount, columnCount, hierarchical)
+      info.setCollectionInfo(collectionInfoCompat)
+    }
+
+    if (view is ReactScrollView) {
+      info.isScrollable = view.scrollEnabled
+    } else if (view is ReactHorizontalScrollView) {
+      info.isScrollable = view.scrollEnabled
+    }
+  }
+}