[BottomNavigation] Support accessibilityLabel, accessibilityHint,…

… and `isAccessibilityElement` (#5736) BottomNavigation tab views were not reflecting some of the UIAccessibility properties of the UITabBarItem objects used to create them. This PR adds support for `accessibilityLabel`, `accessibilityHint`, and `isAccessibilityElement`, including Key-Value Observing (KVO) of changes to the UITabBarItem's properties.
material-components · Nov 19, 2018 · 0affb85 · 0affb85
1 parent a063cd7
commit 0affb85
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diff --git a/components/BottomNavigation/src/MDCBottomNavigationBar.m b/components/BottomNavigation/src/MDCBottomNavigationBar.m
@@ -43,7 +43,9 @@
 static NSString *const kMDCBottomNavigationBarNewString = @"new";
 static NSString *const kMDCBottomNavigationBarTitleString = @"title";
 static NSString *const kMDCBottomNavigationBarAccessibilityIdentifier = @"accessibilityIdentifier";
-
+static NSString *const kMDCBottomNavigationBarAccessibilityLabel = @"accessibilityLabel";
+static NSString *const kMDCBottomNavigationBarAccessibilityHint = @"accessibilityHint";
+static NSString *const kMDCBottomNavigationBarIsAccessibilityElement = @"isAccessibilityElement";
 
 static NSString *const kMDCBottomNavigationBarOfAnnouncement = @"of";
 
@@ -256,6 +258,18 @@ - (void)addObserversToTabBarItems {
            forKeyPath:kMDCBottomNavigationBarAccessibilityIdentifier
               options:NSKeyValueObservingOptionNew
               context:nil];
+    [item addObserver:self
+           forKeyPath:kMDCBottomNavigationBarAccessibilityLabel
+              options:NSKeyValueObservingOptionNew
+              context:nil];
+    [item addObserver:self
+           forKeyPath:kMDCBottomNavigationBarAccessibilityHint
+              options:NSKeyValueObservingOptionNew
+              context:nil];
+    [item addObserver:self
+           forKeyPath:kMDCBottomNavigationBarIsAccessibilityElement
+              options:NSKeyValueObservingOptionNew
+              context:nil];
   }
 }
 
@@ -271,6 +285,9 @@ - (void)removeObserversFromTabBarItems {
                 forKeyPath:kMDCBottomNavigationBarSelectedImageString];
       [item removeObserver:self forKeyPath:kMDCBottomNavigationBarTitleString];
       [item removeObserver:self forKeyPath:kMDCBottomNavigationBarAccessibilityIdentifier];
+      [item removeObserver:self forKeyPath:kMDCBottomNavigationBarAccessibilityLabel];
+      [item removeObserver:self forKeyPath:kMDCBottomNavigationBarAccessibilityHint];
+      [item removeObserver:self forKeyPath:kMDCBottomNavigationBarIsAccessibilityElement];
     }
     @catch (NSException *exception) {
       if (exception) {
@@ -309,6 +326,12 @@ - (void)observeValueForKeyPath:(NSString *)keyPath
       itemView.title = change[kMDCBottomNavigationBarNewString];
     } else if ([keyPath isEqualToString:kMDCBottomNavigationBarAccessibilityIdentifier]) {
       itemView.accessibilityIdentifier = change[kMDCBottomNavigationBarNewString];
+    } else if ([keyPath isEqualToString:kMDCBottomNavigationBarAccessibilityLabel]) {
+      itemView.accessibilityLabel = change[kMDCBottomNavigationBarNewString];
+    } else if ([keyPath isEqualToString:kMDCBottomNavigationBarAccessibilityHint]) {
+      itemView.accessibilityHint = change[kMDCBottomNavigationBarNewString];
+    } else if ([keyPath isEqualToString:kMDCBottomNavigationBarIsAccessibilityElement]) {
+      itemView.isAccessibilityElement = [change[kMDCBottomNavigationBarNewString] boolValue];
     }
   }
 }
@@ -405,6 +428,9 @@ - (void)setItems:(NSArray<UITabBarItem *> *)items {
     itemView.titleBelowIcon = self.titleBelowItem;
     itemView.accessibilityValue = item.accessibilityValue;
     itemView.accessibilityIdentifier = item.accessibilityIdentifier;
+    itemView.accessibilityLabel = item.accessibilityLabel;
+    itemView.accessibilityHint = item.accessibilityHint;
+    itemView.isAccessibilityElement = item.isAccessibilityElement;
     itemView.contentInsets = self.itemsContentInsets;
     itemView.contentVerticalMargin = self.itemsContentVerticalMargin;
     itemView.contentHorizontalMargin = self.itemsContentHorizontalMargin;

diff --git a/components/BottomNavigation/tests/unit/BottomNavigationTests.m b/components/BottomNavigation/tests/unit/BottomNavigationTests.m
@@ -145,6 +145,90 @@ - (void)testAccessibilityIdentifier {
   XCTAssert([bar.itemViews.firstObject.accessibilityIdentifier isEqualToString:newIdentifier]);
 }
 
+- (void)testAccessibilityLabelInitialValue {
+  // Given
+  NSString *initialLabel = @"initialLabel";
+  UITabBarItem *tabBarItem = [[UITabBarItem alloc] initWithTitle:@"Home" image:nil tag:0];
+  tabBarItem.accessibilityLabel = initialLabel;
+  MDCBottomNavigationBar *bar = [[MDCBottomNavigationBar alloc] init];
+  // When
+  bar.items = @[ tabBarItem ];
+
+  // Then
+  XCTAssert([bar.itemViews.firstObject.accessibilityLabel isEqualToString:initialLabel]);
+}
+
+- (void)testAccessibilityLabelValueChanged {
+  // Given
+  NSString *oldLabel = @"oldLabel";
+  NSString *newLabel = @"newLabel";
+  UITabBarItem *tabBarItem = [[UITabBarItem alloc] initWithTitle:@"Home" image:nil tag:0];
+  tabBarItem.accessibilityLabel = oldLabel;
+  MDCBottomNavigationBar *bar = [[MDCBottomNavigationBar alloc] init];
+  bar.items = @[ tabBarItem ];
+
+  // When
+  tabBarItem.accessibilityLabel = newLabel;
+
+  // Then
+  XCTAssert([bar.itemViews.firstObject.accessibilityLabel isEqualToString:newLabel]);
+}
+
+- (void)testAccessibilityHintInitialValue {
+  // Given
+  NSString *initialHint = @"initialHint";
+  UITabBarItem *tabBarItem = [[UITabBarItem alloc] initWithTitle:@"Home" image:nil tag:0];
+  tabBarItem.accessibilityHint = initialHint;
+  MDCBottomNavigationBar *bar = [[MDCBottomNavigationBar alloc] init];
+  // When
+  bar.items = @[ tabBarItem ];
+
+  // Then
+  XCTAssert([bar.itemViews.firstObject.accessibilityHint isEqualToString:initialHint]);
+}
+
+- (void)testAccessibilityHintValueChanged {
+  // Given
+  NSString *oldHint = @"oldHint";
+  NSString *newHint = @"newHint";
+  UITabBarItem *tabBarItem = [[UITabBarItem alloc] initWithTitle:@"Home" image:nil tag:0];
+  tabBarItem.accessibilityHint = oldHint;
+  MDCBottomNavigationBar *bar = [[MDCBottomNavigationBar alloc] init];
+  bar.items = @[ tabBarItem ];
+
+  // When
+  tabBarItem.accessibilityHint = newHint;
+
+  // Then
+  XCTAssert([bar.itemViews.firstObject.accessibilityHint isEqualToString:newHint]);
+}
+
+- (void)testIsAccessibilityElementInitialValue {
+  // Given
+  UITabBarItem *tabBarItem = [[UITabBarItem alloc] initWithTitle:@"Home" image:nil tag:0];
+  tabBarItem.isAccessibilityElement = NO;
+  MDCBottomNavigationBar *bar = [[MDCBottomNavigationBar alloc] init];
+  // When
+  bar.items = @[ tabBarItem ];
+
+  // Then
+  XCTAssert(!bar.itemViews.firstObject.isAccessibilityElement);
+}
+
+- (void)testIsAccessibilityElementValueChanged {
+  // Given
+  UITabBarItem *tabBarItem = [[UITabBarItem alloc] initWithTitle:@"Home" image:nil tag:0];
+  tabBarItem.isAccessibilityElement = NO;
+  MDCBottomNavigationBar *bar = [[MDCBottomNavigationBar alloc] init];
+  bar.items = @[ tabBarItem ];
+
+  // When
+  tabBarItem.isAccessibilityElement = YES;
+
+  // Then
+  XCTAssert(bar.itemViews.firstObject.isAccessibilityElement);
+}
+
 -(void)testTitleVisibility {
   UITabBarItem *item1 = [[UITabBarItem alloc] initWithTitle:@"1" image:nil tag:0];
   UITabBarItem *item2 = [[UITabBarItem alloc] initWithTitle:@"2" image:nil tag:0];