iOS Mobile Design

When to Use This Skill

• Designing iOS app interfaces following Apple HIG
• Building SwiftUI views and layouts
• Implementing iOS navigation patterns (NavigationStack, TabView, sheets)
• Creating adaptive layouts for iPhone and iPad
• Using SF Symbols and system typography
• Building accessible iOS interfaces
• Implementing iOS-specific gestures and interactions
• Designing for Dynamic Type and Dark Mode

Core Concepts

1. Human Interface Guidelines Principles

• iOS: Touch-first, compact displays, portrait orientation
• iPadOS: Larger canvas, multitasking, pointer support
• visionOS: Spatial computing, eye/hand input

2. SwiftUI Layout System

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// Vertical stack with alignment
VStack(alignment: .leading, spacing: 12) {
    Text("Title")
        .font(.headline)
    Text("Subtitle")
        .font(.subheadline)
        .foregroundStyle(.secondary)
}

// Horizontal stack with flexible spacing
HStack {
    Image(systemName: "star.fill")
    Text("Featured")
    Spacer()
    Text("View All")
        .foregroundStyle(.blue)
}
`**Grid Layouts:**`
// Adaptive grid that fills available width
LazyVGrid(columns: [
    GridItem(.adaptive(minimum: 150, maximum: 200))
], spacing: 16) {
    ForEach(items) { item in
        ItemCard(item: item)
    }
}

// Fixed column grid
LazyVGrid(columns: [
    GridItem(.flexible()),
    GridItem(.flexible()),
    GridItem(.flexible())
], spacing: 12) {
    ForEach(items) { item in
        ItemThumbnail(item: item)
    }
}

3. Navigation Patterns

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struct ContentView: View {
    @State private var path = NavigationPath()

    var body: some View {
        NavigationStack(path: $path) {
            List(items) { item in
                NavigationLink(value: item) {
                    ItemRow(item: item)
                }
            }
            .navigationTitle("Items")
            .navigationDestination(for: Item.self) { item in
                ItemDetailView(item: item)
            }
        }
    }
}
`**TabView:**`
struct MainTabView: View {
    @State private var selectedTab = 0

    var body: some View {
        TabView(selection: $selectedTab) {
            HomeView()
                .tabItem {
                    Label("Home", systemImage: "house")
                }
                .tag(0)

            SearchView()
                .tabItem {
                    Label("Search", systemImage: "magnifyingglass")
                }
                .tag(1)

            ProfileView()
                .tabItem {
                    Label("Profile", systemImage: "person")
                }
                .tag(2)
        }
    }
}

4. System Integration

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// Basic symbol
Image(systemName: "heart.fill")
    .foregroundStyle(.red)

// Symbol with rendering mode
Image(systemName: "cloud.sun.fill")
    .symbolRenderingMode(.multicolor)

// Variable symbol (iOS 16+)
Image(systemName: "speaker.wave.3.fill", variableValue: volume)

// Symbol effect (iOS 17+)
Image(systemName: "bell.fill")
    .symbolEffect(.bounce, value: notificationCount)
`**Dynamic Type:**`
// Use semantic fonts
Text("Headline")
    .font(.headline)

Text("Body text that scales with user preferences")
    .font(.body)

// Custom font that respects Dynamic Type
Text("Custom")
    .font(.custom("Avenir", size: 17, relativeTo: .body))

5. Visual Design

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// Semantic colors that adapt to light/dark mode
Text("Primary")
    .foregroundStyle(.primary)
Text("Secondary")
    .foregroundStyle(.secondary)

// System materials for blur effects
Rectangle()
    .fill(.ultraThinMaterial)
    .frame(height: 100)

// Vibrant materials for overlays
Text("Overlay")
    .padding()
    .background(.regularMaterial, in: RoundedRectangle(cornerRadius: 12))
`**Shadows and Depth:**`
// Standard card shadow
RoundedRectangle(cornerRadius: 16)
    .fill(.background)
    .shadow(color: .black.opacity(0.1), radius: 8, y: 4)

// Elevated appearance
.shadow(radius: 2, y: 1)
.shadow(radius: 8, y: 4)
`## Quick Start Component`
import SwiftUI

struct FeatureCard: View {
    let title: String
    let description: String
    let systemImage: String

    var body: some View {
        HStack(spacing: 16) {
            Image(systemName: systemImage)
                .font(.title)
                .foregroundStyle(.blue)
                .frame(width: 44, height: 44)
                .background(.blue.opacity(0.1), in: Circle())

            VStack(alignment: .leading, spacing: 4) {
                Text(title)
                    .font(.headline)
                Text(description)
                    .font(.subheadline)
                    .foregroundStyle(.secondary)
                    .lineLimit(2)
            }

            Spacer()

            Image(systemName: "chevron.right")
                .foregroundStyle(.tertiary)
        }
        .padding()
        .background(.background, in: RoundedRectangle(cornerRadius: 12))
        .shadow(color: .black.opacity(0.05), radius: 4, y: 2)
    }
}

Best Practices

1. Use Semantic Colors: Always use .primary, .secondary, .background for automatic light/dark mode support
2. Embrace SF Symbols: Use system symbols for consistency and automatic accessibility
3. Support Dynamic Type: Use semantic fonts (.body, .headline) instead of fixed sizes
4. Add Accessibility: Include .accessibilityLabel() and .accessibilityHint() modifiers
5. Use Safe Areas: Respect safeAreaInset and avoid hardcoded padding at screen edges
6. Implement State Restoration: Use @SceneStorage for preserving user state
7. Support iPad Multitasking: Design for split view and slide over
8. Test on Device: Simulator doesn't capture full haptic and performance experience

Common Issues

• Layout Breaking: Use .fixedSize() sparingly; prefer flexible layouts
• Performance Issues: Use LazyVStack/LazyHStack for long scrolling lists
• Navigation Bugs: Ensure NavigationLink values are Hashable
• Dark Mode Problems: Avoid hardcoded colors; use semantic or asset catalog colors
• Accessibility Failures: Test with VoiceOver enabled
• Memory Leaks: Watch for strong reference cycles in closures

Resources

• Human Interface Guidelines
• SwiftUI Documentation
• SF Symbols App
• WWDC SwiftUI Sessions