Override default Talkback automatic content grouping and generate a custom contentDescription

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

@@ -16,10 +16,13 @@
 import android.text.Layout;
 import android.text.Spannable;
 import android.text.Spanned;
+import android.text.TextUtils;
 import android.text.style.AbsoluteSizeSpan;
 import android.text.style.ClickableSpan;
 import android.view.View;
+import android.view.ViewGroup;
 import android.view.accessibility.AccessibilityEvent;
+import android.widget.EditText;
 import android.widget.TextView;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
@@ -41,6 +44,7 @@
 import com.facebook.react.bridge.ReadableType;
 import com.facebook.react.bridge.UIManager;
 import com.facebook.react.bridge.WritableMap;
+import com.facebook.react.uimanager.ReactAccessibilityDelegate.AccessibilityRole;
 import com.facebook.react.uimanager.events.Event;
 import com.facebook.react.uimanager.events.EventDispatcher;
 import com.facebook.react.uimanager.util.ReactFindViewUtil;
@@ -59,6 +63,8 @@ public class ReactAccessibilityDelegate extends ExploreByTouchHelper {
   private static int sCounter = 0x3f000000;
   private static final int TIMEOUT_SEND_ACCESSIBILITY_EVENT = 200;
   private static final int SEND_EVENT = 1;
+  private static final String delimiter = ", ";
+  private static final int delimiterLength = delimiter.length();
 
   public static final HashMap<String, Integer> sActionIdMap = new HashMap<>();
 
@@ -319,6 +325,17 @@ public void onInitializeAccessibilityNodeInfo(View host, AccessibilityNodeInfoCo
     if (testId != null) {
       info.setViewIdResourceName(testId);
     }
+    boolean missingContentDescription = TextUtils.isEmpty(info.getContentDescription());
+    boolean missingText = TextUtils.isEmpty(info.getText());
+    boolean missingTextAndDescription = missingContentDescription && missingText;
+    boolean hasContentToAnnounce =
+        accessibilityActions != null
+            || accessibilityState != null
+            || accessibilityLabelledBy != null
+            || accessibilityRole != null;
+    if (missingTextAndDescription && hasContentToAnnounce) {
+      info.setContentDescription(getTalkbackDescription(host, info));
+    }
   }
 
   @Override
@@ -726,4 +743,295 @@ private static class AccessibleLink {
 
     return null;
   }
+
+  /**
+   * Determines if the supplied {@link View} and {@link AccessibilityNodeInfoCompat} has any
+   * children which are not independently accessibility focusable and also have a spoken
+   * description.
+   *
+   * <p>NOTE: Accessibility services will include these children's descriptions in the closest
+   * focusable ancestor.
+   *
+   * @param view The {@link View} to evaluate
+   * @param node The {@link AccessibilityNodeInfoCompat} to evaluate
+   * @return {@code true} if it has any non-actionable speaking descendants within its subtree
+   */
+  public static boolean hasNonActionableSpeakingDescendants(
+      @Nullable AccessibilityNodeInfoCompat node, @Nullable View view) {
+
+    if (node == null || view == null || !(view instanceof ViewGroup)) {
+      return false;
+    }
+
+    final ViewGroup viewGroup = (ViewGroup) view;
+    for (int i = 0, count = viewGroup.getChildCount(); i < count; i++) {
+      final View childView = viewGroup.getChildAt(i);
+
+      if (childView == null) {
+        continue;
+      }
+
+      final AccessibilityNodeInfoCompat childNode = AccessibilityNodeInfoCompat.obtain();
+      try {
+        ViewCompat.onInitializeAccessibilityNodeInfo(childView, childNode);
+
+        if (!childNode.isVisibleToUser()) {
+          continue;
+        }
+
+        if (isAccessibilityFocusable(childNode, childView)) {
+          continue;
+        }
+
+        if (isSpeakingNode(childNode, childView)) {
+          return true;
+        }
+      } finally {
+        if (childNode != null) {
+          childNode.recycle();
+        }
+      }
+    }
+
+    return false;
+  }
+
+  /**
+   * Returns whether the node has valid RangeInfo.
+   *
+   * @param node The node to check.
+   * @return Whether the node has valid RangeInfo.
+   */
+  public static boolean hasValidRangeInfo(@Nullable AccessibilityNodeInfoCompat node) {
+    if (node == null) {
+      return false;
+    }
+
+    @Nullable final RangeInfoCompat rangeInfo = node.getRangeInfo();
+    if (rangeInfo == null) {
+      return false;
+    }
+
+    final float maxProgress = rangeInfo.getMax();
+    final float minProgress = rangeInfo.getMin();
+    final float currentProgress = rangeInfo.getCurrent();
+    final float diffProgress = maxProgress - minProgress;
+    return (diffProgress > 0.0f)
+        && (currentProgress >= minProgress)
+        && (currentProgress <= maxProgress);
+  }
+
+  /**
+   * Returns whether the specified node has state description.
+   *
+   * @param node The node to check.
+   * @return {@code true} if the node has state description.
+   */
+  private static boolean hasStateDescription(@Nullable AccessibilityNodeInfoCompat node) {
+    return node != null
+        && (!TextUtils.isEmpty(node.getStateDescription())
+            || node.isCheckable()
+            || hasValidRangeInfo(node));
+  }
+
+  /**
+   * Returns whether the supplied {@link View} and {@link AccessibilityNodeInfoCompat} would produce
+   * spoken feedback if it were accessibility focused. NOTE: not all speaking nodes are focusable.
+   *
+   * @param view The {@link View} to evaluate
+   * @param node The {@link AccessibilityNodeInfoCompat} to evaluate
+   * @return {@code true} if it meets the criterion for producing spoken feedback
+   */
+  public static boolean isSpeakingNode(
+      @Nullable AccessibilityNodeInfoCompat node, @Nullable View view) {
+    if (node == null || view == null) {
+      return false;
+    }
+
+    final int important = ViewCompat.getImportantForAccessibility(view);
+    if (important == ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_NO_HIDE_DESCENDANTS
+        || (important == ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_NO && node.getChildCount() <= 0)) {
+      return false;
+    }
+
+    return hasText(node)
+        || hasStateDescription(node)
+        || node.isCheckable()
+        || hasNonActionableSpeakingDescendants(node, view);
+  }
+
+  public static boolean hasText(@Nullable AccessibilityNodeInfoCompat node) {
+    return node != null
+        && node.getCollectionInfo() == null
+        && (!TextUtils.isEmpty(node.getText())
+            || !TextUtils.isEmpty(node.getContentDescription())
+            || !TextUtils.isEmpty(node.getHintText()));
+  }
+
+  /**
+   * Determines if the provided {@link View} and {@link AccessibilityNodeInfoCompat} meet the
+   * criteria for gaining accessibility focus.
+   *
+   * <p>Note: this is evaluating general focusability by accessibility services, and does not mean
+   * this view will be guaranteed to be focused by specific services such as Talkback. For Talkback
+   * focusability, see {@link #isTalkbackFocusable(View)}
+   *
+   * @param view The {@link View} to evaluate
+   * @param node The {@link AccessibilityNodeInfoCompat} to evaluate
+   * @return {@code true} if it is possible to gain accessibility focus
+   */
+  public static boolean isAccessibilityFocusable(
+      @Nullable AccessibilityNodeInfoCompat node, @Nullable View view) {
+    if (node == null || view == null) {
+      return false;
+    }
+
+    // Never focus invisible nodes.
+    if (!node.isVisibleToUser()) {
+      return false;
+    }
+
+    // Always focus "actionable" nodes.
+    return node.isScreenReaderFocusable() || isActionableForAccessibility(node);
+  }
+
+  /**
+   * Returns whether a node is actionable. That is, the node supports one of {@link
+   * AccessibilityNodeInfoCompat#isClickable()}, {@link AccessibilityNodeInfoCompat#isFocusable()},
+   * or {@link AccessibilityNodeInfoCompat#isLongClickable()}.
+   *
+   * @param node The {@link AccessibilityNodeInfoCompat} to evaluate
+   * @return {@code true} if node is actionable.
+   */
+  public static boolean isActionableForAccessibility(@Nullable AccessibilityNodeInfoCompat node) {
+    if (node == null) {
+      return false;
+    }
+
+    if (node.isClickable() || node.isLongClickable() || node.isFocusable()) {
+      return true;
+    }
+
+    final List actionList = node.getActionList();
+    return actionList.contains(AccessibilityNodeInfoCompat.ACTION_CLICK)
+        || actionList.contains(AccessibilityNodeInfoCompat.ACTION_LONG_CLICK)
+        || actionList.contains(AccessibilityNodeInfoCompat.ACTION_FOCUS);
+  }
+
+  /**
+   * Returns a cached instance if such is available otherwise a new one.
+   *
+   * @param view The {@link View} to derive the AccessibilityNodeInfo properties from.
+   * @return {@link FlipperObject} containing the properties.
+   */
+  @Nullable
+  public static AccessibilityNodeInfoCompat createNodeInfoFromView(View view) {
+    if (view == null) {
+      return null;
+    }
+
+    final AccessibilityNodeInfoCompat nodeInfo = AccessibilityNodeInfoCompat.obtain();
+
+    // For some unknown reason, Android seems to occasionally throw a NPE from
+    // onInitializeAccessibilityNodeInfo.
+    try {
+      ViewCompat.onInitializeAccessibilityNodeInfo(view, nodeInfo);
+    } catch (NullPointerException e) {
+      if (nodeInfo != null) {
+        nodeInfo.recycle();
+      }
+      return null;
+    }
+
+    return nodeInfo;
+  }
+
+  /**
+   * Creates the text that Google's TalkBack screen reader will read aloud for a given {@link View}.
+   * This may be any combination of the {@link View}'s {@code text}, {@code contentDescription}, and
+   * the {@code text} and {@code contentDescription} of any ancestor {@link View}.
+   *
+   * <p>This description is generally ported over from Google's TalkBack screen reader, and this
+   * should be kept up to date with their implementation (as much as necessary). Details can be seen
+   * in their source code here:
+   *
+   * <p>https://github.com/google/talkback/compositor/src/main/res/raw/compositor.json - search for
+   * "get_description_for_tree", "append_description_for_tree", "description_for_tree_nodes"
+   *
+   * @param view The {@link View} to evaluate.
+   * @param info The default {@link AccessibilityNodeInfoCompat}.
+   * @return {@code String} representing what talkback will say when a {@link View} is focused.
+   */
+  @Nullable
+  public static CharSequence getTalkbackDescription(
+      View view, @Nullable AccessibilityNodeInfoCompat info) {
+    final AccessibilityNodeInfoCompat node =
+        info == null ? createNodeInfoFromView(view) : AccessibilityNodeInfoCompat.obtain(info);
+
+    if (node == null) {
+      return null;
+    }
+    try {
+      final CharSequence contentDescription = node.getContentDescription();
+      final CharSequence nodeText = node.getText();
+
+      final boolean hasNodeText = !TextUtils.isEmpty(nodeText);
+      final boolean isEditText = view instanceof EditText;
+
+      StringBuilder talkbackSegments = new StringBuilder();
+
+      // EditText's prioritize their own text content over a contentDescription so skip this
+      if (!TextUtils.isEmpty(contentDescription) && (!isEditText || !hasNodeText)) {
+        // next add content description
+        talkbackSegments.append(contentDescription);
+        return talkbackSegments;
+      }
+
+      // EditText
+      if (hasNodeText) {
+        // skipped status checks above for EditText
+
+        // description
+        talkbackSegments.append(nodeText);
+        return talkbackSegments;
+      }
+
+      // If there are child views and no contentDescription the text of all non-focusable children,
+      // comma separated, becomes the description.
+      if (view instanceof ViewGroup) {
+        final StringBuilder concatChildDescription = new StringBuilder();
+        final ViewGroup viewGroup = (ViewGroup) view;
+
+        for (int i = 0, count = viewGroup.getChildCount(); i < count; i++) {
+          final View child = viewGroup.getChildAt(i);
+
+          final AccessibilityNodeInfoCompat childNodeInfo = AccessibilityNodeInfoCompat.obtain();
+          ViewCompat.onInitializeAccessibilityNodeInfo(child, childNodeInfo);
+
+          if (isSpeakingNode(childNodeInfo, child)
+              && !isAccessibilityFocusable(childNodeInfo, child)) {
+            CharSequence childNodeDescription = getTalkbackDescription(child, null);
+            if (!TextUtils.isEmpty(childNodeDescription)) {
+              concatChildDescription.append(childNodeDescription + delimiter);
+            }
+          }
+          childNodeInfo.recycle();
+        }
+
+        return removeFinalDelimiter(concatChildDescription);
+      }
+
+      return null;
+    } finally {
+      node.recycle();
+    }
+  }
+
+  private static String removeFinalDelimiter(StringBuilder builder) {
+    int end = builder.length();
+    if (end > 0) {
+      builder.delete(end - delimiterLength, end);
+    }
+    return builder.toString();
+  }
 }