Modern SwiftUI Patterns

SwiftUI has matured significantly. Here's what modern SwiftUI code looks like and the patterns we'll cover.

Follow along with the code: iOS-Practice on GitHub. New here? Read the setup guide to get started.

What We'll Cover

This series explores practical SwiftUI patterns through hands-on exercises:

Lists & Data Loading

• Loading states and error handling
• ContentUnavailableView for empty states
• Pull-to-refresh with .refreshable
• Search and filtering with debouncing

Grids & Layouts

• Photo galleries with LazyVGrid
• Adaptive layouts that respond to screen size
• Animating between grid and list modes

Navigation

• NavigationStack and value-based navigation
• Modal presentations (sheets, full-screen, alerts)
• Passing data back from presented views

State Management

• Form validation patterns
• @StateObject vs @ObservedObject
• Sharing state with EnvironmentObject

The Exercise Structure

Each exercise starts with requirements and builds a complete, working feature:

// MARK: - Exercise: Build a basic list that loads data
// Requirements:
// 1. Show a loading indicator while fetching
// 2. Display users in a List with name, email, and company
// 3. Handle and display errors gracefully
// 4. Add a retry button when an error occurs

Modern SwiftUI Patterns

Throughout the series, you'll see these patterns repeatedly:

State-Driven UI

@State private var users: [User] = []
@State private var isLoading = false
@State private var error: Error?

var body: some View {
    Group {
        if isLoading {
            ProgressView()
        } else if let error {
            ErrorView(error: error)
        } else {
            ContentView(users: users)
        }
    }
}

Async Data Loading

.task {
    await loadData()
}

Built-in Components

ContentUnavailableView("No Results", systemImage: "magnifyingglass")

Why These Patterns Matter

SwiftUI interview questions often focus on:

1. State management - When to use @State, @Binding, @StateObject
2. Navigation - NavigationStack vs NavigationView, value-based links
3. Performance - LazyVStack vs VStack, identity in ForEach
4. Modern APIs - ContentUnavailableView, .refreshable, .searchable

These exercises give you working examples to reference and discuss.

Getting Started

Clone the practice repo and explore the SwiftUIBuilder project:

git clone https://github.com/christopherkmoore/iOS-Practice
cd iOS-Practice/SwiftUIBuilder
open SwiftUIBuilder.xcodeproj

Each exercise is self-contained with its own preview.