Add a semantic isButton flag (flutter#4254)

flutter/flutter#11992
brucewrong · Oct 20, 2017 · 3d01338 · 3d01338
1 parent c39124d
commit 3d01338
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Showing 4 changed files with 17 additions and 3 deletions.
diff --git a/lib/ui/semantics.dart b/lib/ui/semantics.dart
@@ -123,6 +123,7 @@ class SemanticsFlags {
   static const int _kHasCheckedStateIndex = 1 << 0;
   static const int _kIsCheckedIndex = 1 << 1;
   static const int _kIsSelectedIndex = 1 << 2;
+  static const int _kIsButton = 1 << 3;
 
   const SemanticsFlags._(this.index);
 
@@ -153,6 +154,13 @@ class SemanticsFlags {
   /// For example, the active tab in a tab bar has [isSelected] set to true.
   static const SemanticsFlags isSelected = const SemanticsFlags._(_kIsSelectedIndex);
 
+  /// Whether the semantic node represents a button.
+  ///
+  /// Platforms has special handling for buttons, for example Android's TalkBack
+  /// and iOS's VoiceOver provides an additional hint when the focused object is
+  /// a button.
+  static const SemanticsFlags isButton = const SemanticsFlags._(_kIsButton);
+
   /// The possible semantics flags.
   ///
   /// The map's key is the [index] of the flag and the value is the flag itself.

diff --git a/lib/ui/semantics/semantics_node.h b/lib/ui/semantics/semantics_node.h
@@ -38,6 +38,7 @@ enum class SemanticsFlags : int32_t {
   kHasCheckedState = 1 << 0,
   kIsChecked = 1 << 1,
   kIsSelected = 1 << 2,
+  kIsButton = 1 << 3,
 };
 
 struct SemanticsNode {

diff --git a/shell/platform/android/io/flutter/view/AccessibilityBridge.java b/shell/platform/android/io/flutter/view/AccessibilityBridge.java
@@ -56,6 +56,7 @@ class AccessibilityBridge extends AccessibilityNodeProvider implements BasicMess
     private static final int SEMANTICS_FLAG_HAS_CHECKED_STATE = 1 << 0;
     private static final int SEMANTICS_FLAG_IS_CHECKED = 1 << 1;
     private static final int SEMANTICS_FLAG_IS_SELECTED = 1 << 2;
+    private static final int SEMANTICS_FLAG_IS_BUTTON = 1 << 3;
 
     AccessibilityBridge(FlutterView owner) {
         assert owner != null;
@@ -159,6 +160,10 @@ public AccessibilityNodeInfo createAccessibilityNodeInfo(int virtualViewId) {
         result.setSelected((object.flags & SEMANTICS_FLAG_IS_SELECTED) != 0);
         result.setText(object.label);
 
+        if ((object.flags & SEMANTICS_FLAG_IS_BUTTON) != 0) {
+          result.setClassName("android.widget.Button");
+        }
+
         // Accessibility Focus
         if (mFocusedObject != null && mFocusedObject.id == virtualViewId) {
             result.addAction(AccessibilityNodeInfo.ACTION_CLEAR_ACCESSIBILITY_FOCUS);

diff --git a/shell/platform/darwin/ios/framework/Source/accessibility_bridge.mm b/shell/platform/darwin/ios/framework/Source/accessibility_bridge.mm
@@ -164,9 +164,6 @@ - (NSString*)accessibilityLabel {
 
 - (UIAccessibilityTraits)accessibilityTraits {
   UIAccessibilityTraits traits = UIAccessibilityTraitNone;
-  if (_node.HasAction(blink::SemanticsAction::kTap)) {
-    traits |= UIAccessibilityTraitButton;
-  }
   if (_node.HasAction(blink::SemanticsAction::kIncrease) ||
       _node.HasAction(blink::SemanticsAction::kDecrease)) {
     traits |= UIAccessibilityTraitAdjustable;
@@ -175,6 +172,9 @@ - (UIAccessibilityTraits)accessibilityTraits {
       _node.HasFlag(blink::SemanticsFlags::kIsChecked)) {
     traits |= UIAccessibilityTraitSelected;
   }
+  if (_node.HasFlag(blink::SemanticsFlags::kIsButton)) {
+    traits |= UIAccessibilityTraitButton;
+  }
   return traits;
 }