invalidate a11y

Source/ASDisplayNode.mm

@@ -14,6 +14,7 @@
 #import <AsyncDisplayKit/AsyncDisplayKit+Debug.h>
 #import <AsyncDisplayKit/ASLayoutSpec+Subclasses.h>
 #import <AsyncDisplayKit/ASCellNode+Internal.h>
+#import <AsyncDisplayKit/_ASDisplayViewAccessiblity.h>
 
 #import <objc/runtime.h>
 
@@ -2286,6 +2287,7 @@ - (void)_insertSubnode:(ASDisplayNode *)subnode atSubnodeIndex:(NSInteger)subnod
   if (disableNotifications) {
     [subnode __decrementVisibilityNotificationsDisabled];
   }
+  [subnode invalidateAccessibleElementsIfNeeded];
 }
 
 /*
@@ -2620,7 +2622,9 @@ - (void)_removeFromSupernode
   ASDisplayNodeAssertThreadAffinity(self);
   // TODO: Disabled due to PR: https://github.com/TextureGroup/Texture/pull/1204
   // ASAssertUnlocked(__instanceLock__);
-
+
+  [self invalidateAccessibleElementsIfNeeded];
+
   __instanceLock__.lock();
     __weak ASDisplayNode *supernode = _supernode;
     __weak UIView *view = _view;
@@ -3674,6 +3678,48 @@ - (UIAccessibilityTraits)defaultAccessibilityTraits
   return UIAccessibilityTraitNone;
 }
 
+- (void)invalidateAccessibleElementsIfNeeded {
+  // The container needs to reaggregate.
+  [self invalidateUptoContainer];
+
+  // The view needs to reggregate.
+  if (self.isLayerBacked) {
+    [self.supernode invalidateForLayerBackedNodes];
+  }
+}
+
+// Find the first container and invalidated it so that the container can reaggregate next time.
+- (void)invalidateUptoContainer {
+  if (self.isAccessibilityContainer) {
+    if (self.isNodeLoaded) {
+      if (ASDisplayNodeThreadIsMain()) {
+        [ASDynamicCast(self.view, _ASDisplayView) setAccessibilityElements:nil];
+      } else {
+        ASPerformBlockOnMainThread(^{
+          [ASDynamicCast(self.view, _ASDisplayView) setAccessibilityElements:nil];
+        });
+      }
+    }
+    return;
+  }
+  [self.supernode invalidateUptoContainer];
+}
+
+// Find first view up the tree and invalidated it.
+- (void)invalidateForLayerBackedNodes {
+  if (self.isLayerBacked) {
+    [self.supernode invalidateForLayerBackedNodes];
+  } else if (self.isNodeLoaded) {
+    if (ASDisplayNodeThreadIsMain()) {
+      [ASDynamicCast(self.view, _ASDisplayView) setAccessibilityElements:nil];
+    } else {
+      ASPerformBlockOnMainThread(^{
+        [ASDynamicCast(self.view, _ASDisplayView) setAccessibilityElements:nil];
+      });
+    }
+  }
+}
+
 #pragma mark - Debugging (Private)
 
 #if ASEVENTLOG_ENABLE

Source/ASTextNode.mm

@@ -487,6 +487,7 @@ - (void)setAttributedText:(NSAttributedString *)attributedText
   let currentAttributedText = self.attributedText; // Grab attributed string again in case it changed in the meantime
   self.accessibilityLabel = self.defaultAccessibilityLabel;
   self.isAccessibilityElement = (currentAttributedText.length != 0); // We're an accessibility element by default if there is a string.
+  [self invalidateAccessibleElementsIfNeeded];
 
 #if AS_TEXTNODE_RECORD_ATTRIBUTED_STRINGS
   [ASTextNode _registerAttributedText:_attributedText];

Source/ASTextNode2.mm

@@ -410,7 +410,7 @@ - (void)setAttributedText:(NSAttributedString *)attributedText
   // Accessiblity
   self.accessibilityLabel = self.defaultAccessibilityLabel;
   self.isAccessibilityElement = (length != 0); // We're an accessibility element by default if there is a string.
-
+  [self invalidateAccessibleElementsIfNeeded];
 #if AS_TEXTNODE2_RECORD_ATTRIBUTED_STRINGS
   [ASTextNode _registerAttributedText:_attributedText];
 #endif

Source/Details/_ASDisplayView.mm

@@ -285,6 +285,28 @@ - (void)addSubview:(UIView *)view
 #endif
 }
 
+- (void)insertSubview:(UIView *)view atIndex:(NSInteger)index {
+  [super insertSubview:view atIndex:index];
+
+#ifndef ASDK_ACCESSIBILITY_DISABLE
+  self.accessibilityElements = nil;
+#endif
+}
+
+- (void)insertSubview:(UIView *)view aboveSubview:(UIView *)siblingSubview {
+  [super insertSubview:view aboveSubview:siblingSubview];
+#ifndef ASDK_ACCESSIBILITY_DISABLE
+  self.accessibilityElements = nil;
+#endif
+}
+
+- (void)insertSubview:(UIView *)view belowSubview:(UIView *)siblingSubview {
+  [super insertSubview:view aboveSubview:siblingSubview];
+#ifndef ASDK_ACCESSIBILITY_DISABLE
+  self.accessibilityElements = nil;
+#endif
+}
+
 - (void)willRemoveSubview:(UIView *)subview
 {
   [super willRemoveSubview:subview];

Source/Private/ASDisplayNode+FrameworkPrivate.h

@@ -314,6 +314,7 @@ __unused static NSString * _Nonnull NSStringFromASHierarchyStateChange(ASHierarc
 
 @interface ASDisplayNode (AccessibilityInternal)
 - (NSArray *)accessibilityElements;
+- (void)invalidateAccessibleElementsIfNeeded;
 @end;
 
 @interface UIView (ASDisplayNodeInternal)

Tests/ASDisplayViewAccessibilityTests.mm

@@ -14,6 +14,8 @@
 
 #import <AsyncDisplayKit/ASDisplayNode.h>
 #import <AsyncDisplayKit/ASDisplayNode+Beta.h>
+#import <AsyncDisplayKit/ASTextNode.h>
+
 
 @interface ASDisplayViewAccessibilityTests : XCTestCase
 @end
@@ -82,4 +84,206 @@ - (void)testThatContainerAccessibilityLabelOverrideStopsAggregation {
                         [node.view.accessibilityElements.firstObject accessibilityLabel]);
 }
 
+- (void)testAccessibilityLayerbackedNodesOperationInContainer {
+  ASDisplayNode *contianer = [[ASDisplayNode alloc] init];
+  contianer.frame = CGRectMake(50, 50, 200, 400);
+  contianer.backgroundColor = [UIColor grayColor];
+  contianer.isAccessibilityContainer = YES;
+
+  // Do any additional setup after loading the view, typically from a nib.
+  ASTextNode *text1 = [[ASTextNode alloc] init];
+  text1.layerBacked = YES;
+  text1.attributedText = [[NSAttributedString alloc] initWithString:@"hello"];
+  text1.frame = CGRectMake(50, 100, 200, 200);
+  [contianer addSubnode:text1];
+
+  [contianer layoutIfNeeded];
+  [contianer.layer displayIfNeeded];
+
+  NSArray<UIAccessibilityElement *> *elements = contianer.view.accessibilityElements;
+  XCTAssertTrue(elements.count == 1);
+  XCTAssertTrue([[elements.firstObject accessibilityLabel] isEqualToString:@"hello"]);
+
+  ASTextNode *text2 = [[ASTextNode alloc] init];
+  text2.layerBacked = YES;
+  text2.attributedText = [[NSAttributedString alloc] initWithString:@"world"];
+  text2.frame = CGRectMake(50, 300, 200, 200);
+  [contianer addSubnode:text2];
+
+  [contianer layoutIfNeeded];
+  [contianer.layer displayIfNeeded];
+  NSArray<UIAccessibilityElement *> *updatedElements = contianer.view.accessibilityElements;
+  XCTAssertTrue(updatedElements.count == 1);
+  XCTAssertTrue([[updatedElements.firstObject accessibilityLabel] isEqualToString:@"hello, world"]);
+
+  ASTextNode *text3 = [[ASTextNode alloc] init];
+  text3.attributedText = [[NSAttributedString alloc] initWithString:@"!!!!"];
+  text3.frame = CGRectMake(50, 400, 200, 100);
+  text3.layerBacked = YES;
+  [text2 addSubnode:text3];
+  [contianer layoutIfNeeded];
+  [contianer.layer displayIfNeeded];
+  NSArray<UIAccessibilityElement *> *updatedElements2 = contianer.view.accessibilityElements;
+  XCTAssertTrue([[updatedElements2.firstObject accessibilityLabel] isEqualToString:@"hello, world, !!!!"]);
+}
+
+- (void)testAccessibilityNonLayerbackedNodesOperationInContainer {
+  ASDisplayNode *contianer = [[ASDisplayNode alloc] init];
+  contianer.frame = CGRectMake(50, 50, 200, 600);
+  contianer.backgroundColor = [UIColor grayColor];
+  contianer.isAccessibilityContainer = YES;
+
+  // Do any additional setup after loading the view, typically from a nib.
+  ASTextNode *text1 = [[ASTextNode alloc] init];
+  text1.attributedText = [[NSAttributedString alloc] initWithString:@"hello"];
+  text1.frame = CGRectMake(50, 100, 200, 200);
+  [contianer addSubnode:text1];
+
+  [contianer layoutIfNeeded];
+  [contianer.layer displayIfNeeded];
+
+  NSArray<UIAccessibilityElement *> *elements = contianer.view.accessibilityElements;
+  XCTAssertTrue(elements.count == 1);
+  XCTAssertTrue([[elements.firstObject accessibilityLabel] isEqualToString:@"hello"]);
+
+  ASTextNode *text2 = [[ASTextNode alloc] init];
+  text2.attributedText = [[NSAttributedString alloc] initWithString:@"world"];
+  text2.frame = CGRectMake(50, 300, 200, 200);
+  [contianer addSubnode:text2];
+
+  [contianer layoutIfNeeded];
+  [contianer.layer displayIfNeeded];
+  NSArray<UIAccessibilityElement *> *updatedElements = contianer.view.accessibilityElements;
+  XCTAssertTrue(updatedElements.count == 1);
+  XCTAssertTrue([[updatedElements.firstObject accessibilityLabel] isEqualToString:@"hello, world"]);
+
+  ASTextNode *text3 = [[ASTextNode alloc] init];
+  text3.attributedText = [[NSAttributedString alloc] initWithString:@"!!!!"];
+  text3.frame = CGRectMake(50, 400, 200, 100);
+  [text2 addSubnode:text3];
+  [contianer layoutIfNeeded];
+  [contianer.layer displayIfNeeded];
+  NSArray<UIAccessibilityElement *> *updatedElements2 = contianer.view.accessibilityElements;
+  XCTAssertTrue([[updatedElements2.firstObject accessibilityLabel] isEqualToString:@"hello, world, !!!!"]);
+}
+
+- (void)testAccessibilityNonLayerbackedNodesOperationInNonContainer {
+  ASDisplayNode *contianer = [[ASDisplayNode alloc] init];
+  contianer.frame = CGRectMake(50, 50, 200, 600);
+  contianer.backgroundColor = [UIColor grayColor];
+
+  // Do any additional setup after loading the view, typically from a nib.
+  ASTextNode *text1 = [[ASTextNode alloc] init];
+  text1.attributedText = [[NSAttributedString alloc] initWithString:@"hello"];
+  text1.frame = CGRectMake(50, 100, 200, 200);
+  [contianer addSubnode:text1];
+
+  [contianer layoutIfNeeded];
+  [contianer.layer displayIfNeeded];
+
+  NSArray<UIAccessibilityElement *> *elements = contianer.view.accessibilityElements;
+  XCTAssertTrue(elements.count == 1);
+  XCTAssertTrue([[elements.firstObject accessibilityLabel] isEqualToString:@"hello"]);
+
+  ASTextNode *text2 = [[ASTextNode alloc] init];
+  text2.attributedText = [[NSAttributedString alloc] initWithString:@"world"];
+  text2.frame = CGRectMake(50, 300, 200, 200);
+  [contianer addSubnode:text2];
+
+  [contianer layoutIfNeeded];
+  [contianer.layer displayIfNeeded];
+  NSArray<UIAccessibilityElement *> *updatedElements = contianer.view.accessibilityElements;
+  XCTAssertTrue(updatedElements.count == 2);
+  XCTAssertTrue([[updatedElements.firstObject accessibilityLabel] isEqualToString:@"hello"]);
+  XCTAssertTrue([[updatedElements.lastObject accessibilityLabel] isEqualToString:@"world"]);
+
+
+  ASTextNode *text3 = [[ASTextNode alloc] init];
+  text3.attributedText = [[NSAttributedString alloc] initWithString:@"!!!!"];
+  text3.frame = CGRectMake(50, 400, 200, 100);
+  [text2 addSubnode:text3];
+  [contianer layoutIfNeeded];
+  [contianer.layer displayIfNeeded];
+  NSArray<UIAccessibilityElement *> *updatedElements2 = contianer.view.accessibilityElements;
+  //text3 won't be read out cause it's overshadowed by text2
+  XCTAssertTrue(updatedElements2.count == 2);
+  XCTAssertTrue([[updatedElements2.firstObject accessibilityLabel] isEqualToString:@"hello"]);
+  XCTAssertTrue([[updatedElements2.lastObject accessibilityLabel] isEqualToString:@"world"]);
+}
+
+- (void)testAccessibilityLayerbackedNodesOperationInNonContainer {
+  ASDisplayNode *contianer = [[ASDisplayNode alloc] init];
+  contianer.frame = CGRectMake(50, 50, 200, 600);
+  contianer.backgroundColor = [UIColor grayColor];
+
+  // Do any additional setup after loading the view, typically from a nib.
+  ASTextNode *text1 = [[ASTextNode alloc] init];
+  text1.layerBacked = YES;
+  text1.attributedText = [[NSAttributedString alloc] initWithString:@"hello"];
+  text1.frame = CGRectMake(50, 0, 100, 100);
+  [contianer addSubnode:text1];
+
+  [contianer layoutIfNeeded];
+  [contianer.layer displayIfNeeded];
+
+  NSArray<UIAccessibilityElement *> *elements = contianer.view.accessibilityElements;
+  XCTAssertTrue(elements.count == 1);
+  XCTAssertTrue([[elements.firstObject accessibilityLabel] isEqualToString:@"hello"]);
+
+  ASTextNode *text2 = [[ASTextNode alloc] init];
+  text2.layerBacked = YES;
+  text2.attributedText = [[NSAttributedString alloc] initWithString:@"world"];
+  text2.frame = CGRectMake(50, 100, 100, 100);
+  [contianer addSubnode:text2];
+
+  [contianer layoutIfNeeded];
+  [contianer.layer displayIfNeeded];
+  NSArray<UIAccessibilityElement *> *updatedElements = contianer.view.accessibilityElements;
+  XCTAssertTrue(updatedElements.count == 2);
+  XCTAssertTrue([[updatedElements.firstObject accessibilityLabel] isEqualToString:@"hello"]);
+  XCTAssertTrue([[updatedElements.lastObject accessibilityLabel] isEqualToString:@"world"]);
+
+  ASTextNode *text3 = [[ASTextNode alloc] init];
+  text3.layerBacked = YES;
+  text3.attributedText = [[NSAttributedString alloc] initWithString:@"!!!!"];
+  text3.frame = CGRectMake(50, 200, 100, 100);
+  [text2 addSubnode:text3];
+  [contianer layoutIfNeeded];
+  [contianer.layer displayIfNeeded];
+
+  NSArray<UIAccessibilityElement *> *updatedElements2 = contianer.view.accessibilityElements;
+  //text3 won't be read out cause it's overshadowed by text2
+  XCTAssertTrue(updatedElements2.count == 2);
+  XCTAssertTrue([[updatedElements2.firstObject accessibilityLabel] isEqualToString:@"hello"]);
+  XCTAssertTrue([[updatedElements2.lastObject accessibilityLabel] isEqualToString:@"world"]);
+}
+
+- (void)testAccessibilityUpdatesWithElementsChanges {
+  ASDisplayNode *contianer = [[ASDisplayNode alloc] init];
+  contianer.frame = CGRectMake(50, 50, 200, 600);
+  contianer.backgroundColor = [UIColor grayColor];
+  contianer.isAccessibilityContainer = YES;
+  // Do any additional setup after loading the view, typically from a nib.
+  ASTextNode *text1 = [[ASTextNode alloc] init];
+  text1.layerBacked = YES;
+  text1.attributedText = [[NSAttributedString alloc] initWithString:@"hello"];
+  text1.frame = CGRectMake(50, 0, 100, 100);
+  [contianer addSubnode:text1];
+
+  [contianer layoutIfNeeded];
+  [contianer.layer displayIfNeeded];
+
+  NSArray<UIAccessibilityElement *> *elements = contianer.view.accessibilityElements;
+  XCTAssertTrue(elements.count == 1);
+  XCTAssertTrue([[elements.firstObject accessibilityLabel] isEqualToString:@"hello"]);
+
+  text1.attributedText = [[NSAttributedString alloc] initWithString:@"greeting"];
+  [contianer layoutIfNeeded];
+  [contianer.layer displayIfNeeded];
+
+  NSArray<UIAccessibilityElement *> *elements2 = contianer.view.accessibilityElements;
+  XCTAssertTrue(elements2.count == 1);
+  XCTAssertTrue([[elements2.firstObject accessibilityLabel] isEqualToString:@"greeting"]);
+}
+
 @end