#+title:      iOS Development with Swift
#+date:       [2024-07-20 Sat]
#+filetags:   :programming:swift:ios:
#+identifier: 20240720T101500

* SwiftUI Essentials

** State Management

- =@State= — local, value-type state
- =@Binding= — two-way connection to parent state
- =@Observable= — reference type, iOS 17+
- =@EnvironmentObject= — shared across view hierarchy

** Navigation

#+begin_src swift
NavigationStack {
    List(items) { item in
        NavigationLink(destination: DetailView(item: item)) {
            ItemRow(item: item)
        }
    }
}
#+end_src

* Networking

Use =async/await= with =URLSession=:

#+begin_src swift
func fetchData() async throws -> Data {
    let (data, response) = try await URLSession.shared.data(from: url)
    guard (response as? HTTPURLResponse)?.statusCode == 200 else {
        throw NetworkError.badStatus
    }
    return data
}
#+end_src

* Keychain

Store sensitive data (tokens, passwords) in the iOS Keychain, never in UserDefaults.

* Testing

- Unit tests with =XCTest=
- UI tests with =XCUITest=
- Preview testing with =#Preview=