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Ios Dev Skill

by @yhongm

iOS/macOS 开发技能(SwiftUI + UIKit)与 Swift 6.3 语言权威参考合集。覆盖 MVVM/Cocoa 架构、 网络层(URLSession/async-await)、状态管理(@State/@Published/Combine)、依赖注入、 Navigation、性能优化、单元测试/...

Versionv1.0.1
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clawhub install ios-dev-skill

📖 About This Skill


name: ios-dev-skill description: > iOS/macOS 开发技能(SwiftUI + UIKit)与 Swift 6.3 语言权威参考合集。覆盖 MVVM/Cocoa 架构、 网络层(URLSession/async-await)、状态管理(@State/@Published/Combine)、依赖注入、 Navigation、性能优化、单元测试/UI 测试、持久化、App 分发,以及 Swift 完整语法 (类型系统/集合/闭包/协议/泛型/并发)。当用户询问 iOS 开发、SwiftUI、Swift 语法、 Swift 语言任何相关内容时触发。 trigger: iOS 开发|SwiftUI|UIKit|Xcode|Swift 编程|MVVM|iOS 架构|iOS 网络|URLSession|Combine|@State|@Published|iOS 测试|XCTest|Swift 布局|SnapKit|Swift 语法|Swift 类型|Swift 闭包|Swift 泛型|Swift async|Swift await|Swift actor|Swift 代码解释|Swift optional|Swift protocol|Swift struct|Swift class|Swift enum|Swift guard|Swift if let|Swift ??|Swift @escaping|Swift 错误处理|Swift throws|Swift do-catch|Swift 访问控制|Swift extension|Swift 类型转换|Swift Sendable|Swift @propertyWrapper|Swift Property Wrapper|Swift tuple|Swift Optional 解包 tags: - ios - swiftui - uikit - xcode - swift - mvvm - ios-architecture - ios-network hermes: tags: [ios, swiftui, uikit, xcode, swift, mvvm, ios-architecture, ios-network] related_skills: [apple-design, harmonyos-dev] version: "1.0.0" last_updated: "2026-04-23" source: | https://developer.apple.com/documentation/swiftui https://developer.apple.com/documentation/uikit https://developer.apple.com/documentation/xcode https://developer.apple.com/documentation/combine license: MIT


iOS 开发技能

iOS/macOS 应用开发技能,基于 SwiftUI + UIKit。

核心架构

MVVM 架构(SwiftUI)

┌─────────────┐     ┌──────────────┐     ┌─────────────┐
│    View     │ ←── │  ViewModel  │ ←── │   Model    │
│  (SwiftUI)  │     │ (ObservableObject) │   │   (Struct) │
└─────────────┘     └──────────────┘     └─────────────┘
     @StateObject          @Published           @State
     @ObservedObject       @State               let

数据流向: 1. View 订阅 ViewModel 的 @Published 属性 2. ViewModel 处理业务逻辑,调用 Model 3. Model 定义数据结构 4. 状态变化自动触发 View 重新渲染

UIKit 架构对比

| 模式 | 适用场景 | 复杂度 | |------|---------|--------| | MVC | 简单页面 | 低 | | MVVM | 中等复杂度 | 中 | | MVP | 需要解耦 View | 中 | | VIPER | 大型模块化 | 高 | | Coordinator | 导航复杂 | 高 |


iOS 生命周期与状态管理

App 生命周期

| 状态 | 触发时机 | 典型用途 | |------|---------|---------| | didFinishLaunching | App 启动完成 | 初始化配置 | | sceneWillEnterForeground | 从后台恢复 | 刷新数据 | | sceneDidBecomeActive | 获得焦点 | 恢复动画 | | sceneWillResignActive | 失去焦点 | 暂停任务 | | sceneDidEnterBackground | 进入后台 | 保存状态 |

SwiftUI 状态修饰符

@State       // 值类型,值语义
@StateObject  // 引用类型,ObservableObject
@ObservedObject // 外部提供的 ObservableObject
@EnvironmentObject // 环境注入的共享状态
@Published   // 属性观察器,自动触发更新

状态管理对比

| 方式 | 适用场景 | 生命周期 | |------|---------|---------| | @State | 视图私有 | 随视图 | | @StateObject | 模型对象 | 随视图 | | @EnvironmentObject | 跨视图共享 | 随 App | | @AppStorage | UserDefaults | 持久 |


数据持久化

方案对比

| 方案 | 适用数据量 | 类型 | 线程安全 | |------|-----------|------|---------| | UserDefaults | < 1MB | Key-Value | ✅ | | FileManager | 任意 | 文件 | ❌ | | PropertyListEncoder | 中等 | 结构化 | ❌ | | SQLite.swift | 大型 | 关系型 | ✅ | | Core Data | 超大型 | 对象图 | ✅ | | Realm | 超大型 | 对象 | ✅ |

UserDefaults

@AppStorage("username") var username = ""
@AppStorage("theme") var theme = "light"

SQLite.swift

import SQLite

let db = try Connection("db.sqlite3") let users = Table("users") let id = Expression("id") let name = Expression("name")

try db.run(users.insert(name <- "Alice")) for user in try db.prepare(users) { print(user[name]) }


网络与 API

URLSession 封装

enum APIError: Error {
    case invalidURL, noData, decodingError, networkError(Error)
}

func fetch(_ type: T.Type, from url: String) async throws -> T { guard let url = URL(string: url) else { throw APIError.invalidURL } let (data, _) = try await URLSession.shared.data(from: url) do { return try JSONDecoder().decode(T.self, from: data) } catch { throw APIError.decodingError } }

SwiftUI 网络图片

AsyncImage(url: URL(string: "https://...")) { phase in
    switch phase {
    case .empty: ProgressView()
    case .success(let image): image.resizable()
    case .failure: Image(systemName: "photo")
    @unknown default: EmptyView()
    }
}


App 分发与发布

构建配置

| 配置 | 用途 | 代码签名 | |------|------|---------| | Debug | 开发调试 | Development | | Release | App Store | Distribution | | Ad Hoc | 测试分发 | Distribution |

发布检查清单

  • [ ] App Icon 1024×1024
  • [ ] 启动屏(Splash Screen)
  • [ ] Info.plist 权限说明
  • [ ] 隐私政策 URL
  • [ ] TestFlight / App Store Connect 上传
  • [ ] App Store 截图(6.7 / 6.5 / 5.5 英寸)
  • 常用权限声明

    | 权限 | Info.plist Key | |------|---------------| | 相机 | NSCameraUsageDescription | | 照片 | NSPhotoLibraryUsageDescription | | 位置 | NSLocationWhenInUseUsageDescription | | 通知 | 推送证书配置 |


    SwiftUI 基础

    页面结构

    @main
    struct MyApp: App {
        var body: some Scene {
            WindowGroup { ContentView() }
        }
    }

    struct ContentView: View { @State private var count = 0

    var body: some View { VStack(spacing: 20) { Text("Count: \(count)") .font(.largeTitle) Button("Increment") { count += 1 } .buttonStyle(.borderedProminent) } } }

    组件层级

    Window → ViewController → View → Subviews
    NavigationController → ViewController → TableView → Cell
    TabBarController → ViewController × N → NavigationController
    


    状态管理

    | 状态类型 | SwiftUI | UIKit | 生命周期 | |---------|---------|-------|---------| | 本地临时 | @State | local var | 视图存在期间 | | 页面级 | @State | view property | 页面存在期间 | | 应用级 | @AppStorage | UserDefaults | 跨页面持久化 | | 全局共享 | @StateObject | Singleton | 应用生命周期 |

    SwiftUI 状态装饰器

    // @State — 值类型,组件私有
    @State private var text = "Hello"

    // @Binding — 双向绑定 @Binding var isPresented: Bool

    // @StateObject — 引用类型,视图拥有 @StateObject private var viewModel = ViewModel()

    // @ObservedObject — 引用类型,外部传入 @ObservedObject var viewModel: ViewModel

    // @EnvironmentObject — 环境注入的全局状态 @EnvironmentObject var authService: AuthService

    // @AppStorage — 持久化 @AppStorage("username") var username = ""

    UIKit 状态

    // 局部变量
    class ViewController: UIViewController {
        private var data: [String] = []

    override func viewDidLoad() { super.viewDidLoad() data = loadData() } }

    // 视图属性 class ViewController: UIViewController { var initialData: [String] = [] }

    // UserDefaults UserDefaults.standard.string(forKey: "username")

    // Singleton let shared = NetworkManager.shared


    Navigation 导航模式

    SwiftUI NavigationStack(推荐)

    NavigationStack {
        List(users) { user in
            NavigationLink(destination: UserDetailView(user: user)) {
                Text(user.name)
            }
        }
    }
    

    UIKit 导航

    // 导航控制器
    let nav = UINavigationController(rootViewController: HomeVC())
    nav.pushViewController(detailVC, animated: true)
    nav.popViewController(animated: true)

    // TabBar 切换 UITabBarController() ├─ UINavigationController(首页) ├─ UINavigationController(发现) └─ UINavigationController(我的)


    网络层

    SwiftUI + async/await

    actor NetworkService {
        static let shared = NetworkService()

    func fetch(_ type: T.Type, from url: URL) async throws -> T { let (data, _) = try await URLSession.shared.data(from: url) return try JSONDecoder().decode(T.self, from: data) } }

    // 使用 Task { let users = try await NetworkService.shared.fetch([User].self, from: url) }

    UIKit + async/await

    class NetworkManager {
        static let shared = NetworkManager()

    func request(_ type: T.Type, endpoint: String) async throws -> T { guard let url = URL(string: endpoint) else { throw NetworkError.invalidURL } let (data, _) = try await URLSession.shared.data(from: url) return try JSONDecoder().decode(T.self, from: data) } }

    URLSession 完整示例

    import Foundation

    struct User: Codable, Identifiable { let id: String let name: String let email: String }

    enum NetworkError: Error { case invalidURL case requestFailed case decodingFailed case noData }

    class APIClient { private let baseURL = "https://api.example.com" private let session: URLSession

    init() { let config = URLSessionConfiguration.default config.timeoutIntervalForRequest = 30 self.session = URLSession(configuration: config) }

    func get(_ type: T.Type, path: String) async throws -> T { guard let url = URL(string: baseURL + path) else { throw NetworkError.invalidURL }

    var request = URLRequest(url: url) request.httpMethod = "GET" request.setValue("application/json", forHTTPHeaderField: "Content-Type")

    let (data, response) = try await session.data(for: request)

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

    let decoder = JSONDecoder() decoder.keyDecodingStrategy = .convertFromSnakeCase

    do { return try decoder.decode(T.self, from: data) } catch { throw NetworkError.decodingFailed } }

    func post(_ type: T.Type, path: String, body: B) async throws -> T { guard let url = URL(string: baseURL + path) else { throw NetworkError.invalidURL }

    var request = URLRequest(url: url) request.httpMethod = "POST" request.setValue("application/json", forHTTPHeaderField: "Content-Type")

    let encoder = JSONEncoder() encoder.keyEncodingStrategy = .convertToSnakeCase request.httpBody = try encoder.encode(body)

    let (data, response) = try await session.data(for: request)

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

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


    依赖注入

    SwiftUI Environment 注入

    struct ContentView: View {
        @EnvironmentObject var authService: AuthService
        var body: some View { ... }
    }

    // App 层级注入 ContentView() .environmentObject(AuthService())

    UIKit Protocol 注入

    protocol NetworkServiceProtocol {
        func fetchUsers() async throws -> [User]
    }

    class ViewModel { let networkService: NetworkServiceProtocol init(networkService: NetworkServiceProtocol = NetworkService.shared) { self.networkService = networkService } }


    Combine 响应式编程

    Publisher 与 Subscriber

    import Combine

    // Publisher let publisher = PassthroughSubject()

    // Subscriber let cancellable = publisher .filter { $0.count > 3 } .map { $0.uppercased() } .sink { print($0) }

    // Future + Promise func fetchUser(id: Int) -> Future { Future { promise in // 异步操作 promise(.success(user)) } }

    SwiftUI + Combine

    @Published var searchText: String = ""

    var searchResults: AnyPublisher<[User], Never> { $searchText .debounce(for: .milliseconds(300), scheduler: RunLoop.main) .removeDuplicates() .flatMap { query in query.isEmpty ? Just([]).eraseToAnyPublisher() : api.search(query: query) } .receive(on: DispatchQueue.main) .eraseToAnyPublisher() }

    AnyCancellable 内存管理

    swift import Combine

    class ViewModel { private var cancellables = Set()

    func bind() { $searchText .debounce(for: .milliseconds(300), scheduler: RunLoop.main) .sink { [weak self] text in self?.performSearch(text) } .store(in: &cancellables) } }

    // Store in property class AnotherViewModel { @Published var data: [Item] = []

    private var cancellables = Set()

    func subscribe(to api: APIService) { api.itemsPublisher .receive(on: DispatchQueue.main) .sink { [weak self] items in self?.data = items } .store(in: &cancellables) } }

    // 取消订阅 cancellables.removeAll() // 手动取消所有

    
    

    常用 Operators

    | Operator | 用途 | |----------|------| | map | 转换值 | | filter | 过滤值 | | flatMap | 展平嵌套 Publisher | | debounce | 防抖(搜索场景) | | throttle | 节流(滚动场景) | | removeDuplicates | 去重 | | combineLatest | 合并多个 Publisher | | merge | 合并同类型 Publisher | | catch | 错误处理 | | retry | 重试 | | zip | 配对组合 |


    性能优化

    | 场景 | SwiftUI | UIKit | |------|---------|-------| | 列表滚动 | LazyVStack | UITableView/UICollectionView | | 图片缓存 | AsyncImage + 第三方库 | SDWebImage/Kingfisher | | 预取数据 | .task modifier | UITableViewDataSourcePrefetching | | 后台任务 | Task.detached | async/await |

    SwiftUI 列表优化

    swift // ✅ 推荐:LazyVStack List { ForEach(items) { item in ItemView(item: item) } }

    // ❌ 避免:大列表不用 Lazy VStack { ForEach(items) { item in // 全部渲染 ItemView(item: item) } }

    
    

    UIKit 列表优化

    swift // UICollectionView 预加载 func collectionView(_ collectionView: UICollectionView, prefetchItemsAt indexPaths: [IndexPath]) { for indexPath in indexPaths { let item = items[indexPath.item] imageLoader.prefetch(url: item.imageURL) } }
    
    

    测试策略

    单元测试 → ViewModel / Service 逻辑 ↓ UI 测试 → View 渲染 + 交互(XCUITest) ↓ 集成测试 → 模块间交互 ↓ 快照测试 → UI 视觉回归(swift-snapshot-testing)
    
    

    Swift 单元测试示例

    swift import XCTest

    final class UserViewModelTests: XCTestCase { var viewModel: UserListViewModel! var mockService: MockNetworkService!

    override func setUp() { super.setUp() mockService = MockNetworkService() viewModel = UserListViewModel(networkService: mockService) }

    func testLoadUsersSuccess() async { // Given mockService.users = [User(id: "1", name: "John")]

    // When await viewModel.loadUsers()

    // Then XCTAssertEqual(viewModel.users.count, 1) XCTAssertFalse(viewModel.isLoading) } }

    
    

    完整页面示例

    SwiftUI + MVVM

    swift // Model struct User: Identifiable, Codable { let id: String let name: String let email: String }

    // ViewModel @MainActor class UserListViewModel: ObservableObject { @Published var users: [User] = [] @Published var isLoading = false @Published var error: String?

    func loadUsers() async { isLoading = true defer { isLoading = false } do { users = try await api.fetch(User.self, path: "/users") } catch { self.error = error.localizedDescription } } }

    // View struct UserListView: View { @StateObject private var vm = UserListViewModel()

    var body: some View { NavigationStack { Group { if vm.isLoading { ProgressView() } else if let error = vm.error { Text("Error: \(error)") .foregroundColor(.red) } else { List(vm.users) { user in NavigationLink(destination: UserDetailView(user: user)) { HStack { Text(user.name) Spacer() Text(user.email) .foregroundColor(.secondary) } } } } } .navigationTitle("用户") .task { await vm.loadUsers() } } } }

    
    

    UIKit + MVC

    swift import UIKit import SnapKit

    class UserListViewController: UIViewController { private let tableView = UITableView(frame: .zero, style: .insetGrouped) private var users: [User] = []

    override func viewDidLoad() { super.viewDidLoad() setupUI() loadData() }

    private func setupUI() { title = "用户" view.backgroundColor = .systemGroupedBackground

    tableView.delegate = self tableView.dataSource = self tableView.register(UITableViewCell.self, forCellReuseIdentifier: "Cell") view.addSubview(tableView)

    tableView.snp.makeConstraints { make in make.edges.equalToSuperview() } }

    private func loadData() { Task { do { users = try await APIClient.shared.get([User].self, path: "/users") tableView.reloadData() } catch { showError(error) } } } }

    extension UserListViewController: UITableViewDataSource, UITableViewDelegate { func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { return users.count }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell { let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) let user = users[indexPath.row] var config = cell.defaultContentConfiguration() config.text = user.name config.secondaryText = user.email cell.contentConfiguration = config return cell }

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) { tableView.deselectRow(at: indexPath, animated: true) let user = users[indexPath.row] let detailVC = UserDetailViewController(user: user) navigationController?.pushViewController(detailVC, animated: true) } }

    
    

    Swift 语言权威参考

    > 来源:The Swift Programming Language (6.3) > https://docs.swift.org/swift-book/documentation/the-swift-programming-language/ > CC BY 4.0 License

    类型系统

    基本类型

    | 类型 | 说明 | 示例 | |------|------|------| | Int | 整数 | 42, -7 | | Double | 64位浮点 | 3.14159 | | Float | 32位浮点 | 3.14 | | Bool | 布尔 | true / false | | String | 字符串 | "Hello" | | Character | 单字符 | "A" |

    类型推断与注解

    swift let inferred = 42 // Int let annotated: Int = 42 // 显式 Int let pi: Double = 3.14 // Double
    
    

    类型别名

    swift typealias AudioSample = UInt16 typealias Callback = (Int, String) -> Void
    
    

    Optional 可选类型

    定义与解包

    swift // 定义 var serverResponse: String? = nil var response: String! = nil // 隐式解包

    // 解包方式 if let value = optional { print(value) }

    // guard 解包 func process(_ value: String?) { guard let value = value else { return } print(value) }

    // ?? 操作符 let name = optional ?? "default"

    // 链式调用 let upper = optional?.uppercased()

    
    

    Optional 模式

    swift // switch 模式匹配 switch optional { case .some(let value): print(value) case .none: print("nil") }

    // 问号链式调用 person?.address?.city

    
    

    Tuple 元组

    swift // 定义 let httpError = (404, "Not Found") let (code, message) = httpError let onlyCode = httpError.0

    // 命名 let success = (code: 200, message: "OK") success.code success.message

    // 返回多值 func getUser() -> (name: String, age: Int) { return ("Alice", 30) }

    
    

    集合类型

    Array

    swift // 创建 var arr = [Int]() // 空 var arr2 = Array(repeating: 0, count: 5) // [0,0,0,0,0] let literals = [1, 2, 3] // 字面量

    // 操作 arr.append(4) arr.insert(0, at: 0) arr.remove(at: 0) arr.removeLast() arr.first arr.last

    // 遍历 for item in arr { } for (i, v) in arr.enumerated() { }

    
    

    Set

    swift // 创建 var set = Set() let genres: Set = ["Rock", "Jazz"]

    // 操作 set.insert("Pop") set.remove("Rock") set.contains("Jazz")

    // 集合运算 a.union(b) // 并集 a.intersection(b) // 交集 a.subtracting(b) // 差集 a.symmetricDifference(b) // 对称差集

    // 关系 a.isSubset(of: b) a.isSuperset(of: b) a.isDisjoint(with: b)

    
    

    Dictionary

    swift // 创建 var dict = [String: Int]() let capitals = ["CN": "Beijing", "JP": "Tokyo"]

    // 操作 dict["key"] = "value" dict["key"] = nil // 删除 dict.updateValue("v", forKey: "k") // 返回旧值

    // 安全访问 if let value = dict["key"] { }

    // 遍历 for (k, v) in dict { } for key in dict.keys { } for value in dict.values { }

    
    

    函数

    定义与调用

    swift func greet(name: String) -> String { return "Hello, \(name)" } greet(name: "World")

    // 参数标签 func greet(to name: String) -> String { return "Hello, \(name)" } greet(to: "World")

    // 默认参数 func greet(_ name: String = "World") -> String { return "Hello, \(name)" }

    // 可变参数 func sum(_ numbers: Int...) -> Int { return numbers.reduce(0, +) } sum(1, 2, 3, 4, 5)

    // inout 参数 func swap(_ a: inout Int, _ b: inout Int) { let temp = a a = b b = temp }

    
    

    函数类型

    swift var mathFunc: (Int, Int) -> Int = { $0 + $1 }

    // 作为参数 func apply(_ op: (Int, Int) -> Int, _ a: Int, _ b: Int) -> Int { return op(a, b) } apply(mathFunc, 3, 4)

    // 作为返回值 func choose(_ op: Bool) -> (Int, Int) -> Int { return op ? { $0 + $1 } : { $0 - $1 } }

    
    

    嵌套函数

    swift func outer() -> () -> Int { var count = 0 func inner() -> Int { count += 1 return count } return inner }
    
    

    闭包

    基本语法

    swift // 完整语法 { (params) -> ReturnType in statements }

    // 类型推断 { a, b in a + b }

    // 无参数 { () -> Int in 42 }

    // 返回类型推断 { $0 + $1 }

    
    

    尾随闭包

    swift // 不用尾随 arr.map({ (x: Int) -> Int in x * 2 })

    // 尾随闭包 arr.map { $0 * 2 }

    // 最后一个参数是闭包 arr.map { x in x * 2 }

    
    

    @escaping

    swift var handlers: [() -> Void] = []

    func withEscaping(_ handler: @escaping () -> Void) { handlers.append(handler) }

    func withoutEscaping(_ handler: () -> Void) { handler() }

    // 逃逸闭包需要显式 self class MyClass { var x = 10 func test() { withEscaping { self.x = 20 } // 必须显式 withoutEscaping { x = 30 } // 可省略 } }

    
    

    捕获

    swift func makeCounter() -> () -> Int { var count = 0 return { count += 1 return count } } let counter = makeCounter() counter() // 1 counter() // 2
    
    

    枚举

    swift enum Direction { case north, south, east, west }

    let dir: Direction = .north

    // 关联值 enum Result { case success(Data) case failure(Error) }

    // 方法 enum Device { case phone, tablet func description() -> String { switch self { case .phone: return "iPhone" case .tablet: return "iPad" } } }

    // 原始值 enum ASCIIControl: Character { case tab = "\t" case newline = "\n" }

    
    

    结构体与类

    对比

    | 特性 | struct | class | |------|--------|-------| | 类型 | 值类型 | 引用类型 | | 继承 | ❌ | ✅ | | 初始化 | 自动生成 | 手动 | | 析构 | — | ✅ | | 引用计数 | — | ✅ |

    swift struct Point { var x: Double var y: Double // 自动生成 memberwise init }

    class Person { var name: String var age: Int init(name: String, age: Int) { self.name = name self.age = age } }

    
    

    属性

    存储属性

    swift struct FixedRange { var start: Int let end: Int // 常量 }
    
    

    计算属性

    swift struct Rect { var origin: Point var size: Size var center: Point { get { Point(x: origin.x + size.width/2, y: origin.y + size.height/2) } set { origin.x = newValue.x - size.width/2 origin.y = newValue.y - size.height/2 } } }
    
    

    属性包装器

    swift @propertyWrapper struct SmallNumber { private var number: Int var value: Int { get { min(number, 12) } set { number = newValue } } init() { number = 0 } init(wrappedValue: Int) { number = min(wrappedValue, 12) } }

    @SmallNumber var value: Int // 使用

    
    

    属性观察者

    swift class StepCounter { var totalSteps: Int = 0 { willSet { print("will set to \(newValue)") } didSet { print("did set from \(oldValue)") } } }
    
    

    懒加载

    swift class DataManager { lazy var importer = DataImporter() // 首次访问时才创建 }
    
    

    方法

    实例方法

    swift class Counter { var count = 0 func increment() { count += 1 } func increment(by amount: Int) { count += amount } func reset() { count = 0 } }
    
    

    静态/类方法

    swift struct MathUtils { static func sqrt(_ n: Double) -> Double { ... } } MathUtils.sqrt(16)

    // 类方法(可被重写) class Animal { class func info() { print("Animal") } }

    
    

    下标

    swift struct TimesTable { subscript(index: Int) -> Int { return index * multiplier } } let table = TimesTable(multiplier: 3) table[6] // 18

    // 多维下标 struct Matrix { subscript(row: Int, col: Int) -> Double { get { return grid[row * 3 + col] } set { grid[row * 3 + col] = newValue } } }

    
    

    继承

    swift class Vehicle { var speed = 0 func describe() -> String { "speed: \(speed)" } }

    class Bicycle: Vehicle { var hasBasket = false override func describe() -> String { // 调用父类 return super.describe() + ", basket: \(hasBasket)" } }

    // final 类不可被继承 final class FinalClass { }

    
    

    初始化与析构

    初始化

    swift class ShoppingListItem { var name: String var quantity: Int = 1 var completed: Bool = false

    init(name: String, quantity: Int = 1) { self.name = name self.quantity = quantity } }

    // 可失败初始化 struct Animal { let species: String init?(species: String) { if species.isEmpty { return nil } self.species = species } }

    
    

    析构

    swift class FileHandler { var file: FileHandle init() { file = open(...) } deinit { file.close() } }
    
    

    错误处理

    错误处理

    swift // 定义错误 enum NetworkError: Error { case badURL case noData case decodingFailed }

    // 抛出 func fetch() throws -> Data { guard let url = URL(string: "...") else { throw NetworkError.badURL } return try Data(contentsOf: url) }

    // 处理 do { let data = try fetch() } catch NetworkError.badURL { print("Bad URL") } catch { print("Error: \(error)") }

    // try? 转换 Optional let data = try? fetch()

    // try! 强制解包(危险) let data = try! fetch()

    
    

    协议与泛型

    协议

    定义与遵循

    swift protocol ExampleProtocol { var simpleDescription: String { get } mutating func adjust() }

    // 遵循 struct SimpleStructure: ExampleProtocol { var simpleDescription: String = "A simple structure" mutating func adjust() { } }

    // 类遵循 class SimpleClass: ExampleProtocol { var simpleDescription: String = "A simple class" func adjust() { } }

    
    

    协议扩展

    swift extension Collection { func allEven() -> [Element] where Element: Numeric { return self.filter { ($0 as? Int ?? 0) % 2 == 0 } } }
    
    

    泛型

    函数泛型

    swift func swapTwoValues(_ a: inout T, _ b: inout T) { let temp = a a = b b = temp } swapTwoValues(&x, &y)
    
    

    类型约束

    swift func findIndex(of valueToFind: T, in array: [T]) -> Int? { for (index, value) in array.enumerated() { if value == valueToFind { return index } } return nil }
    
    

    泛型类型

    swift struct Stack { var items: [Element] = [] mutating func push(_ item: Element) { items.append(item) } mutating func pop() -> Element { items.removeLast() } }
    
    

    where 子句

    swift func allItemsMatch (_ someContainer: C1, _ anotherContainer: C2) -> Bool where C1.Element == C2.Element, C1.Element: Equatable { // ... }
    
    

    访问控制

    | 修饰符 | 范围 | |--------|------| | open | 任意模块,可被继承 | | public | 任意模块 | | internal | 模块内(默认) | | fileprivate | 当前文件 | | private | 当前作用域 |

    swift public class PublicClass { private var privateVar = 0 fileprivate var fileVar = 0 }
    
    

    扩展

    swift extension Int { var isEven: Bool { return self % 2 == 0 } func repetitions(_ task: () -> Void) { for _ in 0..

    5.isEven // true 3.repetitions { print("Hello") }

    
    

    类型转换

    swift // 类型检查 if item is String { print("String") }

    // 向下转型 if let str = item as? String { print(str) }

    // 强制转型(危险) let str = item as! String

    // Any 和 AnyObject var things: [Any] = [] things.append(42) things.append("string")

    
    

    嵌套类型

    swift struct ChessBoard { enum Piece { case king, queen, rook, bishop, knight, pawn } var board: [[Piece?]] }

    let piece: ChessBoard.Piece = .king

    
    

    Swift 6 并发

    Swift 6 Concurrency

    async/await

    swift func fetchData() async throws -> Data { ... }

    Task { do { let data = try await fetchData() } catch { print(error) } }

    // async let 并行 async let first = fetchData() async let second = anotherFetch() let results = await [first, second]

    
    

    Task

    swift // 创建 let task = Task { await doWork() } let result = await task.value task.cancel()

    // TaskGroup await withTaskGroup(of: Data.self) { group in for url in urls { group.addTask { await fetch(url) } } var results: [Data] = [] for await data in group { results.append(data) } }

    
    

    Actor

    swift actor SafeCounter { private var count = 0 func increment() { count += 1 } func getCount() -> Int { count } }

    // MainActor @MainActor func updateUI() { // UI 更新 }

    
    

    Sendable

    swift struct User: Sendable { let id: String }

    actor SafeLogger: Sendable { // actor 自动 Sendable }

    ---

    避坑指南

    常见错误

    | 错误做法 | 正确做法 | |---------|---------| | ❌ 在主线程执行网络请求 | ✅ async/await 自动后台执行 | | ❌ 不处理网络错误 | ✅ always try-catch + user feedback | | ❌ @State 用于引用类型 | ✅ @StateObject 用于 class | | ❌ 不用 LazyVStack 处理大列表 | ✅ 懒加载避免性能问题 | | ❌ 硬编码 URL | ✅ Configuration/Environment |

    SwiftUI 陷阱

  • ⚠️ @State 复制语义 — @State 修饰的 struct 是值语义,修改会触发重渲染
  • ⚠️ @StateObject 只初始化一次 — 不能在 body 中创建
  • ⚠️ onAppear vs task — task 可取消,onAppear 不行
  • UIKit 陷阱

  • ⚠️ 循环引用 — delegate/closure 记得用 [weak self]
  • ⚠️ 主线程 UI — UI 更新必须在主线程
  • ⚠️ Memory Leak — 及时清理 NotificationCenter 观察者

  • 来源

    > 来源:Apple Developer Documentation(2026-04-23 访问) > - SwiftUI: https://developer.apple.com/documentation/swiftui > - UIKit: https://developer.apple.com/documentation/uikit > - Xcode: https://developer.apple.com/documentation/xcode > - Combine: https://developer.apple.com/documentation/combine > > 更新频率:随 Xcode/iOS 版本迭代


    持久化

    UserDefaults

    适用于:小量配置、用户偏好、简单状态

    swift // SwiftUI @AppStorage("username") var username = "" @AppStorage("isDarkMode") var isDarkMode = false

    // 代码直接访问 UserDefaults.standard.string(forKey: "username") UserDefaults.standard.set("value", forKey: "key")

    
    

    SQLite(生产推荐)

    适用于:结构化数据、离线存储、查询性能

    swift import SQLite

    class DatabaseManager { static let shared = DatabaseManager() private var db: Connection?

    // 表定义 private let users = Table("users") private let id = SQLite.Expression("id") private let name = SQLite.Expression("name") private let email = SQLite.Expression("email")

    init() { do { let path = NSSearchPathForDirectoriesInDomains( .documentDirectory, .userDomainMask, true ).first! db = try Connection("\(path)/sqlite.db") try createTables() } catch { print("Database error: \(error)") } }

    private func createTables() throws { try db?.run(users.create(ifNotExists: true) { t in t.column(id, primaryKey: .autoincrement) t.column(name) t.column(email) }) }

    // CRUD func insertUser(_ user: User) throws { let insert = users.insert( name <- user.name, email <- user.email ) try db?.run(insert) }

    func fetchUsers() throws -> [User] { guard let db = db else { return [] } return try db.prepare(users).map { row in User( id: row[id], name: row[name], email: row[email] ) } }

    func deleteUser(_ userId: Int64) throws { let user = users.filter(id == userId) try db?.run(user.delete()) } }

    
    

    Core Data(苹果官方)

    适用于:复杂对象图、大量关系数据、Apple 生态深度集成

    swift // Core Data Stack class CoreDataManager { static let shared = CoreDataManager()

    lazy var persistentContainer: NSPersistentContainer = { let container = NSPersistentContainer(name: "Model") container.loadPersistentStores { _, error in if let error = error { fatalError("Core Data failed: \(error)") } } container.viewContext.automaticallyMergesChangesFromParent = true return container }()

    var viewContext: NSManagedObjectContext { persistentContainer.viewContext }

    func save() { let context = viewContext if context.hasChanges { do { try context.save() } catch { print("Save error: \(error)") } } } }

    // SwiftUI 集成 struct ContentView: View { @Environment(\.managedObjectContext) var viewContext

    @FetchRequest( sortDescriptors: [NSSortDescriptor(keyPath: \User.name, ascending: true)], animation: .default ) var users: FetchedResults

    var body: some View { List(users, id: \.self) { user in Text(user.name ?? "Unknown") } } }

    
    

    Swift Concurrency 深度

    Sendable 协议

    确保数据可以安全跨并发域传递。

    swift // ✅ 可Sendable的类型 struct User: Sendable { let id: String let name: String // 值类型默认 Sendable }

    // ⚠️ Class 需要手动实现 final class SafeClass: @unchecked Sendable { // 不做线程安全假设,仅用于已知安全的场景 }

    // ❌ 不可Sendable class UnsafeClass { var cache = [String: Any]() // 包含可变状态 }

    
    

    MainActor

    确保代码在主线程执行,用于 UI 更新。

    swift // 方法级别 @MainActor func updateUI() { // 自动在主线程执行 self.username = "New Name" }

    // 类级别(所有方法默认主线程) @MainActor class ViewModel: ObservableObject { @Published var items: [Item] = []

    // 隐式 @MainActor func loadItems() async { let fetched = await network.fetchItems() self.items = fetched // 安全 } }

    // 非隔离函数访问主线程数据 nonisolated func describe(_ vm: ViewModel) { // ❌ 不能访问 @Published // ✅ 可以访问 Sendable 属性 print("Description") }

    
    

    TaskGroup

    并发执行多个任务。

    swift // 并发下载 func fetchAllImages(urls: [URL]) async throws -> [Data] { try await withThrowingTaskGroup(of: Data.self) { group in for url in urls { group.addTask { let (data, _) = try await URLSession.shared.data(from: url) return data } }

    var results: [Data] = [] for try await data in group { results.append(data) } return results } }

    // 带取消 func fetchWithCancel(urls: [URL]) async { await withTaskGroup(of: Data?.self) { group in for url in urls { group.addTask { try? await Task.sleep(nanoseconds: 1_000_000_000) guard !Task.isCancelled else { return nil } let (data, _) = try await URLSession.shared.data(from: url) return data } } } }

    
    

    Task 取消

    swift // 检查取消 func performWork() async throws { for item in items { try Task.checkCancellation() // 抛出 CancellationError // 处理 item } }

    // withTaskCancellationHandler try await withTaskCancellationHandler { try await longRunningWork() } onCancel: { cleanup() }

    // 传递取消 struct DetailView: View { @State private var data: Data? @Environment(\.dismiss) var dismiss

    var body: some View { Button("加载") { Task { data = await fetchData() } } .onDisappear { // 视图消失时自动取消 } } }

    
    

    UIKit 进阶

    UICollectionView

    生产级列表/网格首选。

    swift class CollectionViewController: UIViewController { private var collectionView: UICollectionView! private var dataSource: UICollectionViewDiffableDataSource!

    enum Section: Hashable { case main case featured }

    override func viewDidLoad() { super.viewDidLoad() setupCollectionView() configureDataSource() applySnapshot() }

    private func setupCollectionView() { // Compositional Layout let config = UICollectionLayoutConfiguration( -interSectionSpacing: 16 ) let layout = UICollectionViewCompositionalLayout( sectionProvider: { sectionIndex, environment in let itemSize = NSCollectionLayoutSize( widthDimension: .fractionalWidth(0.5), heightDimension: .fractionalHeight(1.0) ) let item = NSCollectionLayoutItem(layoutSize: itemSize) item.contentInsets = NSDirectionalEdgeInsets( top: 8, leading: 8, bottom: 8, trailing: 8 )

    let groupSize = NSCollectionLayoutSize( widthDimension: .fractionalWidth(1.0), heightDimension: .absolute(180) ) let group = NSCollectionLayoutGroup.horizontal( layoutSize: groupSize, subitems: [item] )

    let section = NSCollectionLayoutSection(group: group) section.contentInsets = NSDirectionalEdgeInsets( top: 0, leading: 16, bottom: 16, trailing: 16 )

    return NSCollectionLayoutSection(section: section) }, configuration: config )

    collectionView = UICollectionView( frame: view.bounds, collectionViewLayout: layout ) collectionView.autoresizingMask = [.flexibleWidth, .flexibleHeight] collectionView.delegate = self view.addSubview(collectionView) }

    private func configureDataSource() { let cellRegistration = UICollectionView.CellRegistration< UICollectionViewCell, Item > { cell, indexPath, item in var config = UIListContentConfiguration.cell() config.text = item.title config.secondaryText = item.subtitle config.image = UIImage(systemName: item.icon) cell.contentConfiguration = config }

    dataSource = UICollectionViewDiffableDataSource( collectionView: collectionView ) { collectionView, indexPath, item in collectionView.dequeueConfiguredReusableCell( using: cellRegistration, for: indexPath, item: item ) } }

    private func applySnapshot() { var snapshot = NSDiffableDataSourceSnapshot() snapshot.appendSections([.main]) snapshot.appendItems(items) dataSource.apply(snapshot, animatingDifferences: true) } }

    extension CollectionViewController: UICollectionViewDelegate { func collectionView( _ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath ) { guard let item = dataSource.itemIdentifier(for: indexPath) else { return } // 处理选择 } }

    
    

    Auto Layout 完整约束

    swift // NSLayoutConstraint 语法 label.translatesAutoresizingMaskIntoConstraints = false NSLayoutConstraint.activate([ label.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 16), label.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -16), label.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 16), label.heightAnchor.constraint(greaterThanOrEqualToConstant: 44) ])

    // 优先级 let highPriority = label.widthAnchor.constraint(equalToConstant: 100) highPriority.priority = .defaultHigh // 750

    let lowPriority = label.widthAnchor.constraint(equalToConstant: 50) lowPriority.priority = .defaultLow // 250

    // 比例约束 label.widthAnchor.constraint(equalTo: view.widthAnchor, multiplier: 0.5)

    // 尺寸约束 label.heightAnchor.constraint(equalTo: label.widthAnchor, multiplier: 1.5)

    
    

    键盘处理

    swift class KeyboardViewController: UIViewController { @IBOutlet weak var scrollView: UIScrollView! @IBOutlet weak var textField: UITextField!

    override func viewDidLoad() { super.viewDidLoad() setupKeyboardObservers() }

    private func setupKeyboardObservers() { NotificationCenter.default.addObserver( self, selector: #selector(keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil ) NotificationCenter.default.addObserver( self, selector: #selector(keyboardWillHide), name: UIResponder.keyboardWillHideNotification, object: nil ) }

    @objc func keyboardWillShow(_ notification: Notification) { guard let keyboardFrame = notification.userInfo?[ UIResponder.keyboardFrameEndUserInfoKey ] as? CGRect else { return }

    let contentInsets = UIEdgeInsets( top: 0, left: 0, bottom: keyboardFrame.height, right: 0 ) scrollView.contentInset = contentInsets scrollView.scrollIndicatorInsets = contentInsets }

    @objc func keyboardWillHide(_ notification: Notification) { scrollView.contentInset = .zero scrollView.scrollIndicatorInsets = .zero }

    @objc func dismissKeyboard() { view.endEditing(true) } }

    // SwiftUI 版本 struct KeyboardAvoidingView: View { @State private var text = "" @FocusState private var isFocused: Bool

    var body: some View { ScrollView { TextField("输入", text: $text) .focused($isFocused) .padding() .background(Color.gray.opacity(0.2)) } .onTapGesture { isFocused = false } } }

    
    

    Swift Concurrency 避坑

    常见错误

    | 错误做法 | 正确做法 | |---------|---------| | ❌ nonisolated 函数访问 @Published | ✅ 用 @MainActor 包装 | | ❌ 跨线程传递 UIView | ✅ 始终在主线程操作 | | ❌ Task 不保存引用 | ✅ 存储 Task 以支持取消 | | ❌ 忘记 CancellationError | ✅ 调用 Task.checkCancellation() | | ❌ actor 内部用锁 | ✅ actor 天然线程安全 | | ❌ 传递非 Sendable 闭包 | ✅ 确保闭包捕获值是 Sendable |

    @MainActor 传递规则

    swift @MainActor class ViewModel { func update() { /* 主线程 */ } }

    // ✅ 正确:await 后自动回到主线程 let vm = ViewModel() Task { @MainActor in await someAsyncMethod() vm.update() // 安全 }

    // ❌ 错误:非隔离上下文访问 Task { await someAsyncMethod() // vm.update() // ❌ 编译错误 }

    
    

    Widget 开发

  • widget.md — TimelineProvider / App Group / Interactive Widget / Lock Screen Widget
  • 国际化与本地化

  • localization.md — NSLocalizedString / String Catalog / 格式化 / RTL / App Store 本地化
  • Swift Concurrency 权威参考

  • swift-concurrency.md — async/await / TaskGroup / MainActor / Actor / Sendable / Swift 6
  • 快速参考

    SwiftUI 状态装饰器速查

    | 装饰器 | 作用域 | 父传子 | 创建者 | |--------|--------|--------|--------| | @State | 局部 | ❌ | 视图 | | @Binding | 局部 | ✅ | 视图 | | @StateObject | 局部 | ❌ | 视图 | | @ObservedObject | 局部 | ✅ | 父视图 | | @EnvironmentObject | 全局 | ✅ | 任意 | | @AppStorage | 全局 | ✅ | UserDefaults | | @SceneStorage | 全局 | ✅ | Scene | | @FocusState | 局部 | ✅ | 视图 | | @ScaledMetric | 局部 | ✅ | 视图 |

    UIKit vs SwiftUI 生命周期

    | 阶段 | UIKit | SwiftUI | |------|-------|---------| | 创建 | init | @State init | | 加载视图 | loadView | body | | 视图加载 | viewDidLoad | .task | | 即将显示 | viewWillAppear | .onAppear | | 已显示 | viewDidAppear | — | | 即将消失 | viewWillDisappear | .onDisappear | | 已消失 | viewDidDisappear | — | | 内存警告 | didReceiveMemoryWarning | .onChange |

    iOS 版本支持速查

    | API | 最低版本 | |-----|---------| | NavigationStack | iOS 16+ | | @MainActor | iOS 16+ / Swift 5.5+ | | SwiftUI Charts | iOS 16+ | | AnyCancellable store | iOS 13+ | | AsyncSequence | Swift 5.5+ | | WidgetKit | iOS 14+ | | Live Activities | iOS 16.1+ | | Interactive Widget | iOS 17+ |

    Auto Layout 速查

    swift // 核心约束 label.translatesAutoresizingMaskIntoConstraints = false NSLayoutConstraint.activate([ label.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 16), label.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -16), label.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor), label.heightAnchor.constraint(greaterThanOrEqualToConstant: 44) ])

    // SnapKit view.snp.makeConstraints { make in make.edges.equalToSuperview().inset(16) make.height.greaterThanOrEqualTo(100) make.width.equalToSuperview().multipliedBy(0.5) }

    // 优先级 .widthAnchor.constraint(equalToConstant: 100).priority = .defaultHigh // 750 .widthAnchor.constraint(equalToConstant: 50).priority = .defaultLow // 250 .widthAnchor.constraint(equalToConstant: 0).priority = .required // 1000

    
    

    网络状态速查

    | 状态 | SwiftUI | UIKit | |------|---------|-------| | 空闲 | isLoading = false | state = .idle | | 加载中 | isLoading = true | state = .loading | | 成功 | @Published var items | delegate?.didFinish | | 错误 | @Published var error | delegate?.didFail |

    Combine 操作符速查

    | 操作符 | 用途 | 示例 | |--------|------|------| | map | 转换值 | .map { $0 * 2 } | | filter | 过滤 | .filter { $0 > 0 } | | flatMap | 展平 | .flatMap { $0.publisher } | | debounce | 防抖 | .debounce(for: .milliseconds(300), scheduler: RunLoop.main) | | throttle | 节流 | .throttle(for: .seconds(1), scheduler: RunLoop.main, latest: true) | | combineLatest | 合并 | Publishers.CombineLatest(a, b) | | merge | 合并同类型 | a.merge(with: b) | | catch | 错误处理 | .catch { Just(default) } | | retry | 重试 | .retry(3) | | zip | 配对 | a.zip(b) |

    Auto Layout 速查

    swift // 核心约束 label.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 16) label.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -16) label.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor) label.heightAnchor.constraint(greaterThanOrEqualToConstant: 44)

    // SnapKit view.snp.makeConstraints { make in make.edges.equalToSuperview().inset(16) make.height.greaterThanOrEqualTo(100) }

    // 优先级 .widthAnchor.constraint(equalToConstant: 100).priority = .defaultHigh .widthAnchor.constraint(equalToConstant: 50).priority = .defaultLow

    
    

    Widget 尺寸速查

    | 尺寸 | 宽度 | 高度 | 用途 | |------|------|------|------| | systemSmall | 155pt | 155pt | 单指标 | | systemMedium | 329pt | 155pt | 双指标 | | systemLarge | 329pt | 345pt | 列表卡片 | | accessoryCircular | — | — | 锁屏圆形 | | accessoryRectangular | — | — | 锁屏矩形 |

    常用尺寸速查

    | 场景 | 尺寸 | |------|------| | 最小点击区域 | 44pt | | 标准间距 | 16pt | | 大间距 | 24pt | | 安全区留边 | 16pt | | TabBar 高度 | 49pt | | NavigationBar 高度 | 44pt | | Widget 圆角 | 20pt | | 按钮圆角 | 8pt | | 图片圆角 | 12pt |

    Swift Concurrency 速查

    swift // async/await func fetch() async throws -> Data

    // Task Task { await fetch() } Task.detached { await fetch() }

    // TaskGroup await withTaskGroup(of: Data.self) { group in group.addTask { await fetch() } }

    // MainActor @MainActor func update() { } Task { @MainActor in update() }

    // Sendable struct User: Sendable { let id: String } actor SafeCounter { }

    // 取消 Task.checkCancellation() Task.isCancelled task.cancel() ``

    生命周期速查

    | 事件 | SwiftUI | UIKit | |------|---------|-------| | 视图出现 | .onAppear | viewDidAppear | | 视图消失 | .onDisappear | viewDidDisappear | | 应用激活 | .onReceive | applicationDidBecomeActive | | 应用休眠 | — | applicationWillResignActive |

    输出格式规范

    当使用本技能回答用户问题时,遵循以下格式:

    回复结构

    1. 直接回答 — 一段简洁的话给出核心答案 2. 代码示例 — 提供完整的 SwiftUI/UIKit 代码(如需) 3. 实现要点 — 关键步骤和注意事项 4. 避坑提醒 — 常见错误+正确做法

    示例回复(网络请求)

    > SwiftUI 推荐使用 async/await 处理网络请求。定义一个 NetworkService actor 封装 URLSession,在 ViewModel 中用 @Published 管理状态。示例:定义 fetch 泛型方法,用 Task 调用并更新 @Published 属性。错误处理用 do-catch`,始终给用户反馈。

    禁用格式

  • ❌ 不要显式分层(避免"第一层/第二层/框架分析"等字眼)
  • ❌ 不要长篇解释概念,要直接给出实现
  • ❌ 不要只给代码片段,要给完整可运行的示例
  • ✅ 输出应是一段干净的话 + 完整代码