Implement UIAccessibilityContainer informal protocol and make error labels accessible

MaterialTextField.xcodeproj/project.pbxproj

@@ -20,6 +20,8 @@
 		CE58F7E01BEBE77E0082924A /* UIImage+MFTint.m in Sources */ = {isa = PBXBuildFile; fileRef = CE58F7D81BEBE77E0082924A /* UIImage+MFTint.m */; };
 		CE58F7E11BEBE77E0082924A /* UITextField+MFClearButton.h in Headers */ = {isa = PBXBuildFile; fileRef = CE58F7D91BEBE77E0082924A /* UITextField+MFClearButton.h */; };
 		CE58F7E21BEBE77E0082924A /* UITextField+MFClearButton.m in Sources */ = {isa = PBXBuildFile; fileRef = CE58F7DA1BEBE77E0082924A /* UITextField+MFClearButton.m */; };
+		CE83F0CF1C2234BE0031E333 /* MFAccessibilityElementProxy.h in Headers */ = {isa = PBXBuildFile; fileRef = CE83F0CD1C2234BE0031E333 /* MFAccessibilityElementProxy.h */; };
+		CE83F0D01C2234BE0031E333 /* MFAccessibilityElementProxy.m in Sources */ = {isa = PBXBuildFile; fileRef = CE83F0CE1C2234BE0031E333 /* MFAccessibilityElementProxy.m */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -49,6 +51,8 @@
 		CE58F7D81BEBE77E0082924A /* UIImage+MFTint.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = "UIImage+MFTint.m"; sourceTree = "<group>"; };
 		CE58F7D91BEBE77E0082924A /* UITextField+MFClearButton.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "UITextField+MFClearButton.h"; sourceTree = "<group>"; };
 		CE58F7DA1BEBE77E0082924A /* UITextField+MFClearButton.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = "UITextField+MFClearButton.m"; sourceTree = "<group>"; };
+		CE83F0CD1C2234BE0031E333 /* MFAccessibilityElementProxy.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = MFAccessibilityElementProxy.h; sourceTree = "<group>"; };
+		CE83F0CE1C2234BE0031E333 /* MFAccessibilityElementProxy.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = MFAccessibilityElementProxy.m; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -112,6 +116,8 @@
 				CE58F7BC1BEBE64C0082924A /* MaterialTextField.h */,
 				CE58F7D31BEBE77E0082924A /* MFTextField.h */,
 				CE58F7D41BEBE77E0082924A /* MFTextField.m */,
+				CE83F0CD1C2234BE0031E333 /* MFAccessibilityElementProxy.h */,
+				CE83F0CE1C2234BE0031E333 /* MFAccessibilityElementProxy.m */,
 				CE58F7D51BEBE77E0082924A /* UIColor+MaterialTextField.h */,
 				CE58F7D61BEBE77E0082924A /* UIColor+MaterialTextField.m */,
 				82125D271BEF36E20017F72C /* UIFont+MaterialTextField.h */,
@@ -144,6 +150,7 @@
 				CE58F7DF1BEBE77E0082924A /* UIImage+MFTint.h in Headers */,
 				CE58F7DD1BEBE77E0082924A /* UIColor+MaterialTextField.h in Headers */,
 				CE58F7E11BEBE77E0082924A /* UITextField+MFClearButton.h in Headers */,
+				CE83F0CF1C2234BE0031E333 /* MFAccessibilityElementProxy.h in Headers */,
 				CE58F7BD1BEBE64C0082924A /* MaterialTextField.h in Headers */,
 				82125D291BEF36E20017F72C /* UIFont+MaterialTextField.h in Headers */,
 				CE58F7DB1BEBE77E0082924A /* MFTextField.h in Headers */,
@@ -249,6 +256,7 @@
 				CE58F7DC1BEBE77E0082924A /* MFTextField.m in Sources */,
 				CE58F7DE1BEBE77E0082924A /* UIColor+MaterialTextField.m in Sources */,
 				CE58F7E21BEBE77E0082924A /* UITextField+MFClearButton.m in Sources */,
+				CE83F0D01C2234BE0031E333 /* MFAccessibilityElementProxy.m in Sources */,
 				CE58F7E01BEBE77E0082924A /* UIImage+MFTint.m in Sources */,
 				82125D2A1BEF36E20017F72C /* UIFont+MaterialTextField.m in Sources */,
 			);

MaterialTextField/MFAccessibilityElementProxy.h

@@ -0,0 +1,21 @@
+//
+//  MFAccessibilityElementProxy.h
+//  MaterialTextField
+//
+//  Created by Adam Sharp on 17/12/2015.
+//  Copyright © 2015 Stephanie Sharp. All rights reserved.
+//
+
+#import <UIKit/UIKit.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface MFAccessibilityElementProxy : UIAccessibilityElement
+
+@property (nonatomic, readonly) NSObject<UIAccessibilityIdentification> *underlyingElement;
+
+- (instancetype)initWithAccessibilityContainer:(id)container underlyingElement:(NSObject<UIAccessibilityIdentification> *)element;
+
+@end
+
+NS_ASSUME_NONNULL_END

MaterialTextField/MFAccessibilityElementProxy.m

@@ -0,0 +1,50 @@
+//
+//  MFAccessibilityElementProxy.m
+//  MaterialTextField
+//
+//  Created by Adam Sharp on 17/12/2015.
+//  Copyright © 2015 Stephanie Sharp. All rights reserved.
+//
+
+#import "MFAccessibilityElementProxy.h"
+
+@implementation MFAccessibilityElementProxy
+
+- (nonnull instancetype)initWithAccessibilityContainer:(nonnull id)container underlyingElement:(nonnull NSObject<UIAccessibilityIdentification> *)element
+{
+    self = [self initWithAccessibilityContainer:container];
+    _underlyingElement = element;
+    return self;
+}
+
+- (NSString *)accessibilityLabel
+{
+    return self.underlyingElement.accessibilityLabel;
+}
+
+- (NSString *)accessibilityHint
+{
+    return self.underlyingElement.accessibilityHint;
+}
+
+- (NSString *)accessibilityValue
+{
+    return self.underlyingElement.accessibilityValue;
+}
+
+- (NSString *)accessibilityIdentifier
+{
+    return self.underlyingElement.accessibilityIdentifier;
+}
+
+- (CGRect)accessibilityFrame
+{
+    return self.underlyingElement.accessibilityFrame;
+}
+
+- (UIAccessibilityTraits)accessibilityTraits
+{
+    return self.underlyingElement.accessibilityTraits;
+}
+
+@end

MaterialTextField/MFTextField.m

@@ -7,6 +7,7 @@
 //
 
 #import "MFTextField.h"
+#import "MFAccessibilityElementProxy.h"
 #import "UIColor+MaterialTextField.h"
 #import "UITextField+MFClearButton.h"
 #import "UIFont+MaterialTextField.h"
@@ -15,6 +16,9 @@
 static NSTimeInterval const MFDefaultAnimationDuration = 0.3;
 
 @interface MFTextField ()
+{
+    NSMutableArray *_accessibilityElements;
+}
 
 @property (nonatomic) CGRect textRect;
 @property (nonatomic) CALayer *underlineLayer;
@@ -34,6 +38,8 @@ @interface MFTextField ()
 @property (nonatomic, readonly) BOOL hasError;
 @property (nonatomic) BOOL errorIsAnimating;
 
+@property (nonatomic, readonly) MFAccessibilityElementProxy *accessibilityProxy;
+
 @end
 
 @implementation MFTextField
@@ -64,10 +70,19 @@ - (void)sharedInit
     [self setupTextField];
     [self setupUnderline];
     [self setupErrorLabel];
+    [self setupAccessibility];
 }
 
 #pragma mark - Setup
 
+- (void)setupAccessibility
+{
+    _accessibilityProxy = [[MFAccessibilityElementProxy alloc] initWithAccessibilityContainer:self underlyingElement:self];
+
+    _accessibilityElements = [NSMutableArray new];
+    [_accessibilityElements addObject:self.accessibilityProxy];
+}
+
 - (void)setDefaults
 {
     self.textPadding = CGSizeMake(0.0f, 8.0f);
@@ -303,6 +318,11 @@ - (BOOL)placeholderIsHidden
     return self.placeholderLabel.alpha == 0.0f;
 }
 
+- (CGRect)accessibilityFrame
+{
+    return [self convertRect:self.textRect toView:self.superview];
+}
+
 #pragma mark - Layout
 
 - (void)layoutSubviews
@@ -537,17 +557,19 @@ - (void)showErrorLabelAnimated:(BOOL)animated
                              [self.superview layoutIfNeeded];
                              self.errorLabel.alpha = 1.0f;
                          } completion:^(BOOL finished) {
-                              self.errorIsAnimating = NO;
-                              // Layout error label without animation if isValid has changed since animation started.
-                              if (!self.hasError) {
-                                  [self hideErrorLabelAnimated:NO];
-                              }
+                             self.errorIsAnimating = NO;
+                             // Layout error label without animation if isValid has changed since animation started.
+                             if (!self.hasError) {
+                                 [self hideErrorLabelAnimated:NO];
+                             }
+                             [self updateErrorLabelAccessibility];
                          }];
     }
     else if (!animated) {
         self.errorLabel.alpha = 1.0f;
         self.errorLabelTopConstraint.constant = [self topPaddingForErrorLabelHidden:NO];
         self.errorLabelHeightConstraint.active = NO;
+        [self updateErrorLabelAccessibility];
     }
 }
 
@@ -559,7 +581,7 @@ - (void)hideErrorLabelAnimated:(BOOL)animated
                               delay:0.0
                             options:UIViewAnimationOptionCurveEaseOut
                          animations:^{
-                            self.errorLabel.alpha = 0.0f;
+                             self.errorLabel.alpha = 0.0f;
                          } completion:^(BOOL finished) {
                              [self.superview layoutIfNeeded];
 
@@ -570,21 +592,23 @@ - (void)hideErrorLabelAnimated:(BOOL)animated
                                                    delay:0.0
                                                  options:UIViewAnimationOptionCurveEaseOut
                                               animations:^{
-                                                    [self.superview layoutIfNeeded];
+                                                  [self.superview layoutIfNeeded];
                                               } completion:^(BOOL finished) {
                                                   self.errorIsAnimating = NO;
                                                   [self updateErrorLabelText];
                                                   // Layout error label without animation if isValid has changed since animation started.
                                                   if (self.hasError) {
                                                       [self showErrorLabelAnimated:NO];
                                                   }
+                                                  [self updateErrorLabelAccessibility];
                                               }];
                          }];
     }
     else if (!animated) {
         self.errorLabel.alpha = 0.0f;
         self.errorLabelTopConstraint.constant = [self topPaddingForErrorLabelHidden:YES];
         self.errorLabelHeightConstraint.active = YES;
+        [self updateErrorLabelAccessibility];
     }
 }
 
@@ -594,6 +618,28 @@ - (void)updateErrorLabelText
     [self.errorLabel sizeToFit];
 }
 
+- (void)updateErrorLabelAccessibility
+{
+    BOOL accessibilityElementsIncludesError = [self indexOfAccessibilityElement:self.errorLabel] != NSNotFound;
+
+    if (self.hasError && accessibilityElementsIncludesError) {
+        return;
+    }
+
+    if (!self.hasError && !accessibilityElementsIncludesError) {
+        return;
+    }
+
+    if (self.hasError) {
+        [_accessibilityElements addObject:self.errorLabel];
+        UIAccessibilityPostNotification(UIAccessibilityLayoutChangedNotification, self.errorLabel);
+    }
+    else {
+        [_accessibilityElements removeObject:self.errorLabel];
+        UIAccessibilityPostNotification(UIAccessibilityLayoutChangedNotification, nil);
+    }
+}
+
 - (CGFloat)topPaddingForErrorLabelHidden:(BOOL)hidden
 {
     CGFloat topPadding = CGRectGetMaxY(self.underlineLayer.frame);
@@ -681,4 +727,31 @@ - (void)prepareForInterfaceBuilder
     [self.errorLabel removeFromSuperview];
 }
 
+#pragma mark - Accessibility
+
+- (BOOL)isAccessibilityElement
+{
+    return NO;
+}
+
+- (NSInteger)indexOfAccessibilityElement:(id)element
+{
+    return [self.accessibilityElements indexOfObject:element];
+}
+
+- (id)accessibilityElementAtIndex:(NSInteger)index
+{
+    return [self.accessibilityElements objectAtIndex:index];
+}
+
+- (NSInteger)accessibilityElementCount
+{
+    return self.accessibilityElements.count;
+}
+
+- (NSArray *)accessibilityElements
+{
+    return _accessibilityElements;
+}
+
 @end

MaterialTextFieldDemo/MaterialTextFieldDemo.xcodeproj/project.pbxproj

@@ -13,9 +13,24 @@
 		8229BFE01B5E2A7600C40181 /* Main.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 8229BFDE1B5E2A7600C40181 /* Main.storyboard */; };
 		8229BFE21B5E2A7600C40181 /* Images.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = 8229BFE11B5E2A7600C40181 /* Images.xcassets */; };
 		8229BFE51B5E2A7600C40181 /* LaunchScreen.xib in Resources */ = {isa = PBXBuildFile; fileRef = 8229BFE31B5E2A7600C40181 /* LaunchScreen.xib */; };
-		CECEC4381BEBECB500FDD23F /* MaterialTextField.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = CE4B7E621BEBE94300CD6620 /* MaterialTextField.framework */; };
+		CE3E46F41C2239B4002D0A92 /* MaterialTextField.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = CE4B7E621BEBE94300CD6620 /* MaterialTextField.framework */; };
+		CE3E46F51C2239B4002D0A92 /* MaterialTextField.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = CE4B7E621BEBE94300CD6620 /* MaterialTextField.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 /* End PBXBuildFile section */
 
+/* Begin PBXCopyFilesBuildPhase section */
+		CE3E46F61C2239B4002D0A92 /* Embed Frameworks */ = {
+			isa = PBXCopyFilesBuildPhase;
+			buildActionMask = 2147483647;
+			dstPath = "";
+			dstSubfolderSpec = 10;
+			files = (
+				CE3E46F51C2239B4002D0A92 /* MaterialTextField.framework in Embed Frameworks */,
+			);
+			name = "Embed Frameworks";
+			runOnlyForDeploymentPostprocessing = 0;
+		};
+/* End PBXCopyFilesBuildPhase section */
+
 /* Begin PBXFileReference section */
 		8229BFD11B5E2A7600C40181 /* MaterialTextFieldDemo.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = MaterialTextFieldDemo.app; sourceTree = BUILT_PRODUCTS_DIR; };
 		8229BFD51B5E2A7600C40181 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
@@ -35,7 +50,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				CECEC4381BEBECB500FDD23F /* MaterialTextField.framework in Frameworks */,
+				CE3E46F41C2239B4002D0A92 /* MaterialTextField.framework in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -103,6 +118,7 @@
 				8229BFCD1B5E2A7600C40181 /* Sources */,
 				8229BFCE1B5E2A7600C40181 /* Frameworks */,
 				8229BFCF1B5E2A7600C40181 /* Resources */,
+				CE3E46F61C2239B4002D0A92 /* Embed Frameworks */,
 			);
 			buildRules = (
 			);