iOS and macOS Development

UIKit Fundamentals

View Controllers

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        setupUI()
    }

    private func setupUI() {
        let label = UILabel()
        label.text = "Hello, iOS!"
        label.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(label)

        NSLayoutConstraint.activate([
            label.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            label.centerYAnchor.constraint(equalTo: view.centerYAnchor)
        ])
    }
}

Auto Layout

// Programmatic constraints
let button = UIButton(type: .system)
button.setTitle("Tap Me", for: .normal)
button.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(button)

NSLayoutConstraint.activate([
    button.topAnchor.constraint(equalTo: label.bottomAnchor, constant: 20),
    button.centerXAnchor.constraint(equalTo: view.centerXAnchor),
    button.widthAnchor.constraint(equalToConstant: 100),
    button.heightAnchor.constraint(equalToConstant: 44)
])

AppKit for macOS

Window Controllers

class MainWindowController: NSWindowController {
    override func windowDidLoad() {
        super.windowDidLoad()

        window?.title = "My macOS App"
        window?.setContentSize(NSSize(width: 800, height: 600))
    }
}

View Controllers

class ViewController: NSViewController {
    override func viewDidLoad() {
        super.viewDidLoad()

        let button = NSButton(title: "Click Me",
                             target: self,
                             action: #selector(buttonClicked))
        button.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(button)

        NSLayoutConstraint.activate([
            button.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            button.centerYAnchor.constraint(equalTo: view.centerYAnchor)
        ])
    }

    @objc private func buttonClicked() {
        let alert = NSAlert()
        alert.messageText = "Button Clicked"
        alert.runModal()
    }
}

Core Data

Data Model

// Person+CoreDataClass.swift
import CoreData

@objc(Person)
public class Person: NSManagedObject {
    @NSManaged public var name: String?
    @NSManaged public var age: Int16
    @NSManaged public var email: String?
}

Core Data Operations

class DataManager {
    static let shared = DataManager()

    lazy var persistentContainer: NSPersistentContainer = {
        let container = NSPersistentContainer(name: "MyApp")
        container.loadPersistentStores { description, error in
            if let error = error {
                fatalError("Unable to load persistent stores: \(error)")
            }
        }
        return container
    }()

    func savePerson(name: String, age: Int16, email: String) {
        let context = persistentContainer.viewContext
        let person = Person(context: context)
        person.name = name
        person.age = age
        person.email = email

        do {
            try context.save()
        } catch {
            print("Failed to save person: \(error)")
        }
    }
}

Networking

URLSession

class NetworkManager {
    static let shared = NetworkManager()

    func fetchData<T: Decodable>(from url: URL) async throws -> T {
        let (data, response) = try await URLSession.shared.data(from: url)

        guard let httpResponse = response as? HTTPURLResponse,
              (200...299).contains(httpResponse.statusCode) else {
            throw NetworkError.invalidResponse
        }

        let decoder = JSONDecoder()
        return try decoder.decode(T.self, from: data)
    }
}

// Usage
struct User: Codable {
    let id: Int
    let name: String
    let email: String
}

Task {
    do {
        let user: User = try await NetworkManager.shared.fetchData(from: url)
        print("Fetched user: \(user.name)")
    } catch {
        print("Error fetching user: \(error)")
    }
}

Next Steps

1. Explore SwiftUI and UIKit in detail
2. Learn about Performance Optimization
3. Study Security Best Practices