Swift accessibility

Swift Accessibility Patterns

SwiftUI Accessibility Modifiers

struct ArticleCard: View {
    let article: Article
    @State private var isFavorite = false

    var body: some View {
        VStack(alignment: .leading) {
            // Merge child elements into one VoiceOver element
            VStack(alignment: .leading) {
                Text(article.title).font(.headline)
                Text(article.summary).font(.subheadline).foregroundStyle(.secondary)
            }
            .accessibilityElement(children: .combine)
            .accessibilityLabel("\(article.title). \(article.summary)")

            Button {
                isFavorite.toggle()
            } label: {
                Image(systemName: isFavorite ? "heart.fill" : "heart")
            }
            .accessibilityLabel(isFavorite ? "Remove from favorites" : "Add to favorites")
            .accessibilityHint("Double tap to toggle favorite status")
            .accessibilityAddTraits(isFavorite ? .isSelected : [])
        }
    }
}

Dynamic Type

// Always use dynamic type styles — never hardcode font sizes
Text("Article Title")
    .font(.headline)                      // scales with user font size setting
    .dynamicTypeSize(.small ... .xxxLarge) // clamp if layout breaks at extremes

// Adaptive layout for large text
ViewThatFits(in: .horizontal) {
    HStack { icon; text }  // preferred: side by side
    VStack { icon; text }  // fallback: stacked for large text
}

VoiceOver Custom Actions

struct SwipeableCard: View {
    let item: Item

    var body: some View {
        CardView(item: item)
            .accessibilityActions {
                Button("Mark as Read") { markRead(item) }
                Button("Archive") { archive(item) }
                Button("Delete", role: .destructive) { delete(item) }
            }
    }
}

Focus Management

struct LoginView: View {
    @AccessibilityFocusState private var isUsernameFocused: Bool

    var body: some View {
        VStack {
            TextField("Username", text: $username)
                .accessibilityFocused($isUsernameFocused)

            if showError {
                Text("Invalid username")
                    .foregroundStyle(.red)
                    .accessibilityAddTraits(.isStaticText)
            }

            Button("Log In") { login() }
        }
        .onAppear { isUsernameFocused = true }
    }
}

UIKit Accessibility

// Custom accessible element
class CustomSliderView: UIView {
    var value: Float = 0 {
        didSet { accessibilityValue = "\(Int(value * 100))%" }
    }

    override var accessibilityTraits: UIAccessibilityTraits {
        get { [.adjustable] }
        set { }
    }

    override func accessibilityIncrement() { value = min(1, value + 0.1) }
    override func accessibilityDecrement() { value = max(0, value - 0.1) }
}

// Announce changes to VoiceOver
UIAccessibility.post(notification: .announcement, argument: "Upload complete")

// Screen changed (after modal presentation)
UIAccessibility.post(notification: .screenChanged, argument: firstFocusableElement)

High Contrast and Color Independence

// Never rely on color alone to convey information
// Bad: red = error, green = success (color-blind users can't tell)
// Good: add icon + label

struct StatusBadge: View {
    let status: Status

    var body: some View {
        Label(status.label, systemImage: status.iconName)
            .foregroundStyle(status.color)  // color as secondary signal only
    }
}

// Check for increased contrast
@Environment(\.colorSchemeContrast) var contrast
if contrast == .increased {
    // Use higher contrast variant
}

// Use adaptive colors
Color("AccentColor")  // defined in Asset Catalog with dark/light/high-contrast variants

Testing Accessibility

// UI Test with VoiceOver
func testFavoriteButtonAccessibility() {
    let app = XCUIApplication()
    app.launch()

    let favoriteButton = app.buttons["Add to favorites"]
    XCTAssertTrue(favoriteButton.exists)

    favoriteButton.tap()
    XCTAssertTrue(app.buttons["Remove from favorites"].exists)
}

// Check for accessibility audit in Xcode 15+
func testA11yAudit() throws {
    let app = XCUIApplication()
    app.launch()
    try app.performAccessibilityAudit()
}

Accessibility Checklist

• All interactive elements have accessibilityLabel
• Image-only buttons have descriptive labels (not "button")
• Custom controls implement accessibilityTraits correctly
• Dynamic Type tested at all sizes (especially xxxLarge)
• Color is not the only differentiator
• Reduced motion respected
• Focus order is logical
• Error messages announced via UIAccessibility.post

Common Anti-Patterns

• Image("icon").accessibilityLabel("icon") — describe the purpose, not the visual
• accessibilityHidden(true) on meaningful elements — only hide decorative elements
• Hardcoded font sizes — always use Dynamic Type
• Layout that breaks at xxxLarge text — test and use ViewThatFits
• Ignoring accessibilityAudit — run it in CI to catch regressions early