Add SemanticsFlag for Header (flutter#4752)

JackCho · Mar 6, 2018 · 7f7634f · 7f7634f
1 parent 1b7325c
commit 7f7634f
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Showing 4 changed files with 18 additions and 1 deletion.
diff --git a/lib/ui/semantics.dart b/lib/ui/semantics.dart
@@ -223,6 +223,7 @@ class SemanticsFlag {
   static const int _kHasEnabledStateIndex = 1 << 6;
   static const int _kIsEnabledIndex = 1 << 7;
   static const int _kIsInMutuallyExclusiveGroupIndex = 1 << 8;
+  static const int _kIsHeaderIndex = 1 << 9;
 
   const SemanticsFlag._(this.index);
 
@@ -292,6 +293,13 @@ class SemanticsFlag {
   /// only one radio button in that group can be marked as [isChecked].
   static const SemanticsFlag isInMutuallyExclusiveGroup = const SemanticsFlag._(_kIsInMutuallyExclusiveGroupIndex);
 
+  /// Whether a semantic node is a header that divides content into sections.
+  ///
+  /// For example, headers can be used to divide a list of alphabetically
+  /// sorted words into the sections A, B, C, etc. as can be found in many
+  /// address book applications.
+  static const SemanticsFlag isHeader = const SemanticsFlag._(_kIsHeaderIndex);
+
   /// The possible semantics flags.
   ///
   /// The map's key is the [index] of the flag and the value is the flag itself.
@@ -305,6 +313,7 @@ class SemanticsFlag {
     _kHasEnabledStateIndex: hasEnabledState,
     _kIsEnabledIndex: isEnabled,
     _kIsInMutuallyExclusiveGroupIndex: isInMutuallyExclusiveGroup,
+    _kIsHeaderIndex: isHeader,
   };
 
   @override
@@ -328,6 +337,8 @@ class SemanticsFlag {
         return 'SemanticsFlag.isEnabled';
       case _kIsInMutuallyExclusiveGroupIndex:
         return 'SemanticsFlag.isInMutuallyExclusiveGroup';
+      case _kIsHeaderIndex:
+        return 'SemanticsFlag.isHeader';
     }
     return null;
   }

diff --git a/lib/ui/semantics/semantics_node.h b/lib/ui/semantics/semantics_node.h
@@ -53,6 +53,8 @@ enum class SemanticsFlags : int32_t {
   kIsFocused = 1 << 5,
   kHasEnabledState = 1 << 6,
   kIsEnabled = 1 << 7,
+  kIsInMutuallyExclusiveGroup = 1 << 8,
+  kIsHeader = 1 << 9,
 };
 
 struct SemanticsNode {

diff --git a/shell/platform/android/io/flutter/view/AccessibilityBridge.java b/shell/platform/android/io/flutter/view/AccessibilityBridge.java
@@ -83,7 +83,8 @@ enum Flag {
         IS_FOCUSED(1 << 5),
         HAS_ENABLED_STATE(1 << 6),
         IS_ENABLED(1 << 7),
-        IS_IN_MUTUALLY_EXCLUSIVE_GROUP(1 << 8);
+        IS_IN_MUTUALLY_EXCLUSIVE_GROUP(1 << 8),
+        IS_HEADER(1 << 9);
 
         Flag(int value) {
             this.value = value;

diff --git a/shell/platform/darwin/ios/framework/Source/accessibility_bridge.mm b/shell/platform/darwin/ios/framework/Source/accessibility_bridge.mm
@@ -318,6 +318,9 @@ - (UIAccessibilityTraits)accessibilityTraits {
       ![self node].HasFlag(blink::SemanticsFlags::kIsEnabled)) {
     traits |= UIAccessibilityTraitNotEnabled;
   }
+  if ([self node].HasFlag(blink::SemanticsFlags::kIsHeader)) {
+    traits |= UIAccessibilityTraitHeader;
+  }
   return traits;
 }