Accessible Mobile Developer

// Basic accessibility labels
Image("profile-photo")
    .accessibilityLabel("Profile photo of \(user.name)")

Button(action: deleteItem) {
    Image(systemName: "trash")
}
.accessibilityLabel("Delete item")
.accessibilityHint("Double tap to permanently delete this item")

// Grouping related elements
HStack {
    Image(systemName: "star.fill")
    Text("4.5 out of 5 stars")
    Text("(128 reviews)")
}
.accessibilityElement(children: .combine)
// VoiceOver reads: "star.fill, 4.5 out of 5 stars, 128 reviews"

// Better: provide a custom combined label
.accessibilityElement(children: .ignore)
.accessibilityLabel("Rating: 4.5 out of 5 stars from 128 reviews")

// Value and adjustable controls
Slider(value: $volume, in: 0...100)
    .accessibilityLabel("Volume")
    .accessibilityValue("\(Int(volume)) percent")

// Custom actions
Text(message.body)
    .accessibilityAction(named: "Reply") { replyToMessage() }
    .accessibilityAction(named: "Forward") { forwardMessage() }
    .accessibilityAction(named: "Delete") { deleteMessage() }

// SwiftUI handles Dynamic Type automatically with system fonts
Text("Hello")
    .font(.body)  // Automatically scales with user's text size setting

// For custom fonts, use relative sizing
Text("Hello")
    .font(.custom("MyFont", size: 17, relativeTo: .body))

// Limit scaling for layout-sensitive areas
Text("Tab Label")
    .font(.caption2)
    .dynamicTypeSize(...DynamicTypeSize.accessibility1)
    // Scales up to accessibility1 size, then stops

// Handle layout changes at large text sizes
@Environment(\.dynamicTypeSize) var typeSize

var body: some View {
    if typeSize >= .accessibility1 {
        // Stack vertically at very large sizes
        VStack { content }
    } else {
        // Horizontal layout at normal sizes
        HStack { content }
    }
}

// Test with: Settings > Accessibility > Display & Text Size > Larger Text

// Mark elements with their role
Text("Breaking News")
    .accessibilityAddTraits(.isHeader)  // VoiceOver announces "heading"

Button("Play") { }
    .accessibilityAddTraits(.startsMediaSession)

Toggle("Notifications", isOn: $notificationsOn)
    // SwiftUI Toggle already has correct traits

// Custom components need manual trait assignment
struct CustomCheckbox: View {
    @Binding var isChecked: Bool

    var body: some View {
        Image(systemName: isChecked ? "checkmark.square" : "square")
            .accessibilityAddTraits(isChecked ? [.isSelected] : [])
            .accessibilityLabel("Accept terms")
            .accessibilityHint("Double tap to toggle")
            .onTapGesture { isChecked.toggle() }
    }
}

// Content descriptions
Image(
    painter = painterResource(R.drawable.profile),
    contentDescription = "Profile photo of ${user.name}"
)

// Decorative images (skip for screen readers)
Image(
    painter = painterResource(R.drawable.decorative_line),
    contentDescription = null  // TalkBack skips this
)

// Grouping related elements
Row(
    modifier = Modifier.semantics(mergeDescendants = true) {
        contentDescription = "Rating: 4.5 out of 5 stars from 128 reviews"
    }
) {
    Icon(Icons.Filled.Star, contentDescription = null)
    Text("4.5")
    Text("(128 reviews)")
}

// Custom actions
Text(
    text = message.body,
    modifier = Modifier.semantics {
        customActions = listOf(
            CustomAccessibilityAction("Reply") { replyToMessage(); true },
            CustomAccessibilityAction("Forward") { forwardMessage(); true },
            CustomAccessibilityAction("Delete") { deleteMessage(); true }
        )
    }
)

// Headings for navigation
Text(
    text = "Settings",
    modifier = Modifier.semantics { heading() },
    style = MaterialTheme.typography.headlineMedium
)

// Minimum touch target: 48dp x 48dp (Android), 44pt x 44pt (iOS)
// Compose automatically enforces minimum 48dp for clickable elements

// If visual size must be smaller, expand touch area:
IconButton(
    onClick = { /* action */ },
    modifier = Modifier.size(48.dp)  // touch target
) {
    Icon(
        Icons.Default.Close,
        contentDescription = "Close",
        modifier = Modifier.size(24.dp)  // visual size
    )
}

// For custom components, use minimumInteractiveComponentSize
Box(
    modifier = Modifier
        .minimumInteractiveComponentSize()
        .clickable { onItemClick() }
) {
    // Content can be smaller than 48dp
    // Touch area will still be at least 48dp
}

// Support system font scaling
Text(
    text = "Hello",
    style = MaterialTheme.typography.bodyLarge  // Uses sp units, scales automatically
)

// For layout adaptation at large font sizes
@Composable
fun AdaptiveLayout(content: @Composable () -> Unit) {
    val fontScale = LocalDensity.current.fontScale

    if (fontScale > 1.3f) {
        Column { content() }  // Stack vertically at large text
    } else {
        Row { content() }     // Side by side at normal text
    }
}

// Never use fixed dp for text size -- always use sp
// BAD: fontSize = 16.dp (won't scale)
// GOOD: fontSize = 16.sp (scales with user preference)

// Basic accessibility
<TouchableOpacity
  accessible={true}
  accessibilityLabel="Delete item"
  accessibilityHint="Double tap to permanently remove"
  accessibilityRole="button"
  onPress={handleDelete}
>
  <Icon name="trash" />
</TouchableOpacity> .// Grouping
<View accessible={true} accessibilityLabel="4.5 out of 5 stars, 128 reviews">
  <StarIcon />
  <Text>4.5</Text>
  <Text>(128 reviews)</Text>
</View> .// Live regions (announcements)
<Text accessibilityLiveRegion="polite">
  {statusMessage}
</Text> .// State
<TouchableOpacity
  accessibilityState={{ selected: isSelected, disabled: isDisabled }}
>
  <Text>{label}</Text>
</TouchableOpacity>

// Semantics widget for custom accessibility
Semantics(
  label: 'Delete item',
  hint: 'Double tap to permanently remove',
  button: true,
  child: GestureDetector(
    onTap: handleDelete,
    child: Icon(Icons.delete),
  ),
)

// Exclude decorative elements
Semantics(
  excludeSemantics: true,
  child: Image.asset('decorative_border.png'),
)

// Merge semantics for grouped content
MergeSemantics(
  child: Row(
    children: [
      Icon(Icons.star),
      Text('4.5 out of 5 stars'),
    ],
  ),
)