Building iOS Apps with Swift: Cloud Integration

Introduction to Swift

Swift is Apple's powerful programming language for iOS, macOS, watchOS, and tvOS. Learn how to build iOS apps that integrate with cloud APIs.

Setting Up Swift Project

// ViewController.swift
import UIKit

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        fetchDataFromAPI()
    }
    
    func fetchDataFromAPI() {
        guard let url = URL(string: "https://api.example.com/data") else { return }
        
        URLSession.shared.dataTask(with: url) { data, response, error in
            if let error = error {
                print("Error: \(error)")
                return
            }
            
            guard let data = data else { return }
            
            do {
                let json = try JSONSerialization.jsonObject(with: data)
                print("Data: \(json)")
            } catch {
                print("JSON Error: \(error)")
            }
        }.resume()
    }
}

Making API Calls

struct APIService {
    static func fetchUsers(completion: @escaping ([User]) -> Void) {
        guard let url = URL(string: "https://api.example.com/users") else { return }
        
        var request = URLRequest(url: url)
        request.httpMethod = "GET"
        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
        
        URLSession.shared.dataTask(with: request) { data, response, error in
            guard let data = data, error == nil else { return }
            
            do {
                let users = try JSONDecoder().decode([User].self, from: data)
                DispatchQueue.main.async {
                    completion(users)
                }
            } catch {
                print("Decode error: \(error)")
            }
        }.resume()
    }
}

Best Practices

• Use Codable for JSON parsing
• Handle errors gracefully
• Update UI on main thread
• Use async/await in Swift 5.5+
• Implement proper error handling