Check UISwitch state using combination of trait and value

Example/AccessibilitySnapshot/SwitchControlViewController.swift

@@ -91,26 +91,36 @@ private extension SwitchControlViewController {
 
             switchControls.forEach { addSubview($0) }
 
+            let switchTrait = UIAccessibilityTraits(rawValue: 0x0020000000000000)
+
             // Add a fake switch that has the switch button trait only, but is not a UISwitch.
-            fakeSwitchView.isAccessibilityElement = true
-            fakeSwitchView.accessibilityLabel = "Fake Label"
-            fakeSwitchView.accessibilityValue = "Value"
-            fakeSwitchView.accessibilityTraits.insert(UIAccessibilityTraits(rawValue: 0x0020000000000000))
-            fakeSwitchView.frame.size = .init(width: 48, height: 32)
-            fakeSwitchView.backgroundColor = .lightGray
-            fakeSwitchView.layer.cornerRadius = 16
-            addSubview(fakeSwitchView)
-
-            // Add a fake switch that has the switch button and button traits, but is not a UISwitch.
-            fakeSwitchButton.isAccessibilityElement = true
-            fakeSwitchButton.accessibilityLabel = "Fake Label"
-            fakeSwitchButton.accessibilityValue = "Value"
-            fakeSwitchButton.accessibilityTraits.insert(.button)
-            fakeSwitchButton.accessibilityTraits.insert(UIAccessibilityTraits(rawValue: 0x0020000000000000))
-            fakeSwitchButton.frame.size = .init(width: 48, height: 32)
-            fakeSwitchButton.backgroundColor = .lightGray
-            fakeSwitchButton.layer.cornerRadius = 16
-            addSubview(fakeSwitchButton)
+            for fakeSwitchView in fakeSwitchViews {
+                fakeSwitchView.isAccessibilityElement = true
+                fakeSwitchView.accessibilityLabel = "Fake Label"
+                fakeSwitchView.frame.size = .init(width: 48, height: 32)
+                fakeSwitchView.backgroundColor = .lightGray
+                fakeSwitchView.layer.cornerRadius = 16
+            }
+
+            fakeSwitchViews[0].accessibilityValue = "1"
+            fakeSwitchViews[0].accessibilityTraits = [switchTrait, .button]
+
+            fakeSwitchViews[1].accessibilityValue = "0"
+            fakeSwitchViews[1].accessibilityTraits = [switchTrait, .button]
+
+            fakeSwitchViews[2].accessibilityValue = "2"
+            fakeSwitchViews[2].accessibilityTraits = [switchTrait, .button]
+
+            fakeSwitchViews[3].accessibilityValue = "1"
+            fakeSwitchViews[3].accessibilityTraits = [switchTrait]
+
+            fakeSwitchViews[4].accessibilityValue = "3"
+            fakeSwitchViews[4].accessibilityTraits = [switchTrait]
+
+            fakeSwitchViews[5].accessibilityValue = "Value"
+            fakeSwitchViews[5].accessibilityTraits = [.button, switchTrait]
+
+            fakeSwitchViews.forEach { addSubview($0) }
         }
 
         @available(*, unavailable)
@@ -122,11 +132,8 @@ private extension SwitchControlViewController {
 
         private let switchControls: [UISwitch] = (0..<9).map { _ in UISwitch() }
 
-        /// UIView with the switch button trait that acts like a switch, but is not a UISwitch.
-        private let fakeSwitchView: UIView = .init()
-
-        /// UIView with the button and switch button traits that acts like a switch, but is not a UISwitch.
-        private let fakeSwitchButton: UIView = .init()
+        /// `UIView`s with the switch button trait that act like a switch, but aren't actually switches.
+        private let fakeSwitchViews: [UIView] = (0..<6).map { _ in UIView() }
 
         // MARK: - UIView
 
@@ -136,18 +143,10 @@ private extension SwitchControlViewController {
             let statusBarHeight = window?.windowScene?.statusBarManager?.statusBarFrame.height ?? 0
 
             var distributionSpecifiers: [ViewDistributionSpecifying] = [ statusBarHeight.fixed, 1.flexible ]
-            for subview in switchControls {
+            for subview in (switchControls + fakeSwitchViews) {
                 distributionSpecifiers.append(subview)
                 distributionSpecifiers.append(1.flexible)
             }
-            distributionSpecifiers.append(
-                contentsOf: [
-                    fakeSwitchView.distributionItem,
-                    1.flexible,
-                    fakeSwitchButton.distributionItem,
-                    1.flexible,
-                ]
-            )
             applyVerticalSubviewDistribution(distributionSpecifiers)
         }
 

Sources/AccessibilitySnapshot/Core/Swift/Assets/en.lproj/Localizable.strings

@@ -35,10 +35,10 @@
 "trait.search_field.description" = "Search Field.";
 
 /* Description for the 'switch button' accessibility trait, when the switch is on */
-"trait.switch_button.state_on.description" = "Switch Button. On.";
+"trait.switch_button.state_on.description" = "On.";
 
 /* Description for the 'switch button' accessibility trait, when the switch is off */
-"trait.switch_button.state_off.description" = "Switch Button. Off.";
+"trait.switch_button.state_off.description" = "Off.";
 
 /* Description for the 'switch button' accessibility trait, when the state of the switch cannot be determined */
 "trait.switch_button.state_unspecified.description" = "Switch Button.";

Sources/AccessibilitySnapshot/Core/Swift/Classes/UIAccessibility+SnapshotAdditions.swift

@@ -107,20 +107,24 @@ extension NSObject {
         }
 
         if accessibilityTraits.contains(.switchButton) {
-            if let `self` = self as? UISwitch {
-                if self.isOn {
-                    traitSpecifiers.append(strings.switchButtonOnTraitName)
-                } else {
-                    traitSpecifiers.append(strings.switchButtonOffTraitName)
-                }
-
-            } else if accessibilityTraits.contains(.button) {
-                // An element can have the private switch button trait without being a UISwitch (for example, by passing through
-                // the traits of a contained switch). In this case, VoiceOver will still read the "Switch Button." trait, but
-                // will not read whether or not the switch is turned on. If the element's traits do not also include the `.button`
-                // trait, VoiceOver will not read the trait description.
+            if accessibilityTraits.contains(.button) {
+                // An element can have the private switch button trait without being a UISwitch (for example, by passing
+                // through the traits of a contained switch). In this case, VoiceOver will still read the "Switch
+                // Button." trait, but only if the element's traits also include the `.button` trait.
                 traitSpecifiers.append(strings.switchButtonStatelessTraitName)
             }
+
+            switch accessibilityValue {
+            case "1":
+                traitSpecifiers.append(strings.switchButtonOnTraitName)
+            case "0":
+                traitSpecifiers.append(strings.switchButtonOffTraitName)
+            case "2":
+                traitSpecifiers.append(strings.switchButtonMixedTraitName)
+            default:
+                // When the switch button trait is set, unknown accessibility values are omitted from the description.
+                break
+            }
         }
 
         let showsTabTraitInContext = context?.showsTabTrait ?? false
@@ -308,6 +312,8 @@ extension NSObject {
 
         let switchButtonOffTraitName: String
 
+        let switchButtonMixedTraitName: String
+
         let switchButtonStatelessTraitName: String
 
         let switchButtonTraitHint: String
@@ -396,16 +402,21 @@ extension NSObject {
                 comment: "Description for the 'search field' accessibility trait",
                 locale: locale
             )
-            self.switchButtonOnTraitName = "Switch Button. On.".localized(
+            self.switchButtonOnTraitName = "On.".localized(
                 key: "trait.switch_button.state_on.description",
                 comment: "Description for the 'switch button' accessibility trait, when the switch is on",
                 locale: locale
             )
-            self.switchButtonOffTraitName = "Switch Button. Off.".localized(
+            self.switchButtonOffTraitName = "Off.".localized(
                 key: "trait.switch_button.state_off.description",
                 comment: "Description for the 'switch button' accessibility trait, when the switch is off",
                 locale: locale
             )
+            self.switchButtonMixedTraitName = "Mixed.".localized(
+                key: "trait.switch_button.state_mixed.description",
+                comment: "Description for the 'switch button' accessibility trait, when the switch is in a mixed state",
+                locale: locale
+            )
             self.switchButtonStatelessTraitName = "Switch Button.".localized(
                 key: "trait.switch_button.state_unspecified.description",
                 comment: "Description for the 'switch button' accessibility trait, when the state of the switch cannot be determined",