Make scrollable unfocusable when voiceover is running (flutter#27118)

Author: chunhtai

shell/platform/darwin/ios/framework/Source/FlutterViewController.mm

@@ -1228,7 +1228,8 @@ - (void)onAccessibilityStatusChanged:(NSNotification*)notification {
   platformView->SetSemanticsEnabled(true);
   platformView->SetAccessibilityFeatures(flags);
 #else
-  bool enabled = UIAccessibilityIsVoiceOverRunning() || UIAccessibilityIsSwitchControlRunning();
+  _isVoiceOverRunning = UIAccessibilityIsVoiceOverRunning();
+  bool enabled = _isVoiceOverRunning || UIAccessibilityIsSwitchControlRunning();
   if (enabled)
     flags |= static_cast<int32_t>(flutter::AccessibilityFeatureFlag::kAccessibleNavigation);
   platformView->SetSemanticsEnabled(enabled || UIAccessibilityIsSpeakScreenEnabled());

shell/platform/darwin/ios/framework/Source/FlutterViewController_Internal.h

@@ -26,6 +26,7 @@ extern NSNotificationName const FlutterViewControllerShowHomeIndicator;
 @interface FlutterViewController ()
 
 @property(nonatomic, readonly) BOOL isPresentingViewController;
+@property(nonatomic, readonly) BOOL isVoiceOverRunning;
 - (fml::WeakPtr<FlutterViewController>)getWeakPtr;
 - (std::shared_ptr<flutter::FlutterPlatformViewsController>&)platformViewsController;
 - (FlutterRestorationPlugin*)restorationPlugin;

shell/platform/darwin/ios/framework/Source/SemanticsObject.mm

@@ -193,12 +193,6 @@ - (void)accessibilityBridgeDidFinishUpdate {
   [self setFrame:[_semanticsObject accessibilityFrame]];
   [self setContentSize:[self contentSizeInternal]];
   [self setContentOffset:[self contentOffsetInternal] animated:NO];
-  if (self.contentSize.width > self.frame.size.width ||
-      self.contentSize.height > self.frame.size.height) {
-    self.isAccessibilityElement = YES;
-  } else {
-    self.isAccessibilityElement = NO;
-  }
 }
 
 - (void)setChildren:(NSArray<SemanticsObject*>*)children {
@@ -219,6 +213,18 @@ - (id)accessibilityContainer {
   return _container.get();
 }
 
+- (BOOL)isAccessibilityElement {
+  if (![_semanticsObject isAccessibilityBridgeAlive]) {
+    return NO;
+  }
+  if (self.contentSize.width > self.frame.size.width ||
+      self.contentSize.height > self.frame.size.height) {
+    return !_semanticsObject.bridge->isVoiceOverRunning();
+  } else {
+    return NO;
+  }
+}
+
 // private methods
 
 - (float)scrollExtentMax {

shell/platform/darwin/ios/framework/Source/SemanticsObjectTest.mm

@@ -31,6 +31,7 @@
     window_ = [[UIWindow alloc] initWithFrame:kScreenSize];
     [window_ addSubview:view_];
   }
+  bool isVoiceOverRunning() const override { return isVoiceOverRunningValue; }
   UIView* view() const override { return view_; }
   UIView<UITextInput>* textInputView() override { return nil; }
   void DispatchSemanticsAction(int32_t id, SemanticsAction action) override {
@@ -49,6 +50,7 @@ void AccessibilityObjectDidLoseFocus(int32_t id) override {}
     return nil;
   }
   std::vector<SemanticsActionObservation> observations;
+  bool isVoiceOverRunningValue;
 
  private:
   UIView* view_;
@@ -344,6 +346,30 @@ - (void)testFlutterScrollableSemanticsObjectIsNotHittestable {
   XCTAssertEqual([scrollable hitTest:CGPointMake(10, 10) withEvent:nil], nil);
 }
 
+- (void)testFlutterScrollableSemanticsObjectIsHiddenWhenVoiceOverIsRunning {
+  flutter::MockAccessibilityBridge* mock = new flutter::MockAccessibilityBridge();
+  mock->isVoiceOverRunningValue = false;
+  fml::WeakPtrFactory<flutter::AccessibilityBridgeIos> factory(mock);
+  fml::WeakPtr<flutter::AccessibilityBridgeIos> bridge = factory.GetWeakPtr();
+
+  flutter::SemanticsNode node;
+  node.flags = static_cast<int32_t>(flutter::SemanticsFlags::kHasImplicitScrolling);
+  node.actions = flutter::kHorizontalScrollSemanticsActions;
+  node.rect = SkRect::MakeXYWH(0, 0, 100, 200);
+  node.scrollExtentMax = 100.0;
+  node.scrollPosition = 0.0;
+
+  FlutterSemanticsObject* delegate = [[FlutterSemanticsObject alloc] initWithBridge:bridge uid:0];
+  FlutterScrollableSemanticsObject* scrollable =
+      [[FlutterScrollableSemanticsObject alloc] initWithSemanticsObject:delegate];
+  SemanticsObject* scrollable_object = static_cast<SemanticsObject*>(scrollable);
+  [scrollable_object setSemanticsNode:&node];
+  [scrollable_object accessibilityBridgeDidFinishUpdate];
+  XCTAssertTrue(scrollable_object.isAccessibilityElement);
+  mock->isVoiceOverRunningValue = true;
+  XCTAssertFalse(scrollable_object.isAccessibilityElement);
+}
+
 - (void)testSemanticsObjectBuildsAttributedString {
   fml::WeakPtrFactory<flutter::AccessibilityBridgeIos> factory(
       new flutter::MockAccessibilityBridge());

shell/platform/darwin/ios/framework/Source/accessibility_bridge.h

@@ -18,9 +18,9 @@
 #include "flutter/lib/ui/semantics/custom_accessibility_action.h"
 #include "flutter/lib/ui/semantics/semantics_node.h"
 #import "flutter/shell/platform/darwin/common/framework/Headers/FlutterChannels.h"
-#import "flutter/shell/platform/darwin/ios/framework/Headers/FlutterViewController.h"
 #import "flutter/shell/platform/darwin/ios/framework/Source/FlutterTextInputPlugin.h"
 #import "flutter/shell/platform/darwin/ios/framework/Source/FlutterView.h"
+#import "flutter/shell/platform/darwin/ios/framework/Source/FlutterViewController_Internal.h"
 #import "flutter/shell/platform/darwin/ios/framework/Source/SemanticsObject.h"
 #import "flutter/shell/platform/darwin/ios/framework/Source/accessibility_bridge_ios.h"
 #include "third_party/skia/include/core/SkRect.h"
@@ -68,6 +68,8 @@ class AccessibilityBridge final : public AccessibilityBridgeIos {
 
   UIView* view() const override { return view_controller_.view; }
 
+  bool isVoiceOverRunning() const override { return view_controller_.isVoiceOverRunning; }
+
   fml::WeakPtr<AccessibilityBridge> GetWeakPtr();
 
   std::shared_ptr<FlutterPlatformViewsController> GetPlatformViewsController() const override {

shell/platform/darwin/ios/framework/Source/accessibility_bridge_ios.h

@@ -21,6 +21,7 @@ class AccessibilityBridgeIos {
  public:
   virtual ~AccessibilityBridgeIos() = default;
   virtual UIView* view() const = 0;
+  virtual bool isVoiceOverRunning() const = 0;
   virtual UIView<UITextInput>* textInputView() = 0;
   virtual void DispatchSemanticsAction(int32_t id, flutter::SemanticsAction action) = 0;
   virtual void DispatchSemanticsAction(int32_t id,

shell/platform/darwin/ios/framework/Source/accessibility_bridge_test.mm

@@ -224,6 +224,32 @@ - (void)testUpdateSemanticsOneNode {
   OCMVerifyAll(mockFlutterView);
 }
 
+- (void)testIsVoiceOverRunning {
+  flutter::MockDelegate mock_delegate;
+  auto thread_task_runner = CreateNewThread("AccessibilityBridgeTest");
+  flutter::TaskRunners runners(/*label=*/self.name.UTF8String,
+                               /*platform=*/thread_task_runner,
+                               /*raster=*/thread_task_runner,
+                               /*ui=*/thread_task_runner,
+                               /*io=*/thread_task_runner);
+  auto platform_view = std::make_unique<flutter::PlatformViewIOS>(
+      /*delegate=*/mock_delegate,
+      /*rendering_api=*/flutter::IOSRenderingAPI::kSoftware,
+      /*platform_views_controller=*/nil,
+      /*task_runners=*/runners);
+  id mockFlutterView = OCMClassMock([FlutterView class]);
+  id mockFlutterViewController = OCMClassMock([FlutterViewController class]);
+  OCMStub([mockFlutterViewController view]).andReturn(mockFlutterView);
+  OCMStub([mockFlutterViewController isVoiceOverRunning]).andReturn(YES);
+
+  __block auto bridge =
+      std::make_unique<flutter::AccessibilityBridge>(/*view_controller=*/mockFlutterViewController,
+                                                     /*platform_view=*/platform_view.get(),
+                                                     /*platform_views_controller=*/nil);
+
+  XCTAssertTrue(bridge->isVoiceOverRunning());
+}
+
 - (void)testSemanticsDeallocated {
   @autoreleasepool {
     flutter::MockDelegate mock_delegate;