iOS - Swift 开发规范

import SomeModule

let myClass = MyModule.UsefulClass()

func namePickerView(_ namePickerView: NamePickerView, didSelectName name: String)
func namePickerViewShouldReload(_ namePickerView: NamePickerView) -> Bool

func didSelectName(namePicker: NamePickerViewController, name: String)
func namePickerShouldReload() -> Bool

let selector = #selector(viewDidLoad)
view.backgroundColor = .red
let toView = context.view(forKey: .to)
let view = UIView(frame: .zero)

let selector = #selector(ViewController.viewDidLoad)
view.backgroundColor = UIColor.red
let toView = context.view(forKey: UITransitionContextViewKey.to)
let view = UIView(frame: CGRect.zero)

struct Stack<Element> { ... }
func write<Target: OutputStream>(to target: inout Target)
func swap<T>(_ a: inout T, _ b: inout T)

struct Stack<T> { ... }
func write<target: OutputStream>(to target: inout target)
func swap<Thing>(_ a: inout Thing, _ b: inout Thing)

let color = "red"

let colour = "red"

class MyViewController: UIViewController {
  // 类填充在这
}

// MARK: - UITableViewDataSource
extension MyViewController: UITableViewDataSource {
  // table view 的数据源方法
}

// MARK: - UIScrollViewDelegate
extension MyViewController: UIScrollViewDelegate {
  // scroll view 的代理方法
}

class MyViewController: UIViewController, UITableViewDataSource, UIScrollViewDelegate {
  // 所有方法
}

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
  return Database.contacts.count
}

override func didReceiveMemoryWarning() {
  super.didReceiveMemoryWarning()
  // 任何可以重建资源的处理。
}

override func numberOfSections(in tableView: UITableView) -> Int {
  // #warning 未完成的实现，返回节数。
  return 1
}

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
  // #warning 未完成的实现，返回行数。
  return Database.contacts.count
}

if user.isHappy
{
  // 做一件事
}
else {
  // 做另一件事
}

class TestDatabase : Database {
  var data :[String:CGFloat] = ["A" : 1.2, "B":3.2]
}

class Circle: Shape {
  var x: Int, y: Int
  var radius: Double
  var diameter: Double {
    get {
      return radius * 2
    }
    set {
      radius = newValue / 2
    }
  }

  init(x: Int, y: Int, radius: Double) {
    self.x = x
    self.y = y
    self.radius = radius
  }

  convenience init(x: Int, y: Int, diameter: Double) {
    self.init(x: x, y: y, radius: diameter / 2)
  }

  override func area() -> Double {
    return Double.pi * radius * radius
  }
}

extension Circle: CustomStringConvertible {
  var description: String {
    return "center = \(centerString) area = \(area())"
  }
  private var centerString: String {
    return "(\(x),\(y))"
  }
}

var diameter: Double {
  return radius * 2
}

var diameter: Double {
  get {
    return radius * 2
  }
}

// 用这个 Box 类将任何一般类型转换为引用类型。
final class Box<T> {
  let value: T
  init(_ value: T) {
    self.value = value
  }
}

func reticulateSplines(spline: [Double]) -> Bool {
  // 在这里写网格代码
}

func reticulateSplines(spline: [Double], adjustmentFactor: Double,
    translateConstant: Int, comment: String) -> Bool {
  // 在这里写网络代码
}

let success = reticulateSplines(splines)

let success = reticulateSplines(
  spline: splines,
  adjustmentFactor: 1.3,
  translateConstant: 2,
  comment: "normalize the display")

UIView.animate(withDuration: 1.0) {
  self.myView.alpha = 0
}

UIView.animate(withDuration: 1.0, animations: {
  self.myView.alpha = 0
}, completion: { finished in
  self.myView.removeFromSuperview()
})

UIView.animate(withDuration: 1.0, animations: {
  self.myView.alpha = 0
})

UIView.animate(withDuration: 1.0, animations: {
  self.myView.alpha = 0
}) { f in
  self.myView.removeFromSuperview()
}

attendeeList.sort { a, b in
  a > b
}

let value = numbers.map { $0 * 2 }.filter { $0 % 3 == 0 }.index(of: 90)

let value = numbers
  .map {$0 * 2}
  .filter {$0 > 50}
  .map {$0 + 10}

let width = 120.0                                    // Double
let widthString = (width as NSNumber).stringValue    // String

let width: NSNumber = 120.0                          // NSNumber
let widthString: NSString = width.stringValue        // NSString

enum Math {
  static let e = 2.718281828459045235360287
  static let root2 = 1.41421356237309504880168872
}

let hypotenuse = side * Math.root2

self.textContainer?.textLabel?.setNeedsDisplay()

if let textContainer = self.textContainer {
  // 用 textContainer 做很多事情
}

var subview: UIView?
var volume: Double?

// later on...
if let subview = subview, let volume = volume {
  // 使用展开的 subview 和 volume 做某件事
}

var optionalSubview: UIView?
var volume: Double?

if let unwrappedSubview = optionalSubview {
  if let realVolume = volume {
    // 使用 unwrappedSubview 和 volume 做某件事
  }
}

lazy var locationManager: CLLocationManager = self.makeLocationManager()

private func makeLocationManager() -> CLLocationManager {
  let manager = CLLocationManager()
  manager.desiredAccuracy = kCLLocationAccuracyBest
  manager.delegate = self
  manager.requestAlwaysAuthorization()
  return manager
}

let message = "Click the button"
let currentBounds = computeViewBounds()
var names = ["Mic", "Sam", "Christine"]
let maximumWidth: CGFloat = 106.5

let message: String = "Click the button"
let currentBounds: CGRect = computeViewBounds()
let names = [String]()

var names: [String] = []
var lookup: [String: Int] = [:]

var names = [String]()
var lookup = [String: Int]()

var deviceModels: [String]
var employees: [Int: String]
var faxNumber: Int?

var deviceModels: Array<String>
var employees: Dictionary<Int, String>
var faxNumber: Optional<Int>

let sorted = items.mergeSorted()  // 容易领悟的
rocket.launch()  // 模型的行为

let sorted = mergeSort(items)  // 难以领悟的
launch(&rocket)
自由函数异常

let tuples = zip(a, b)  // 作为自由函数感到自然（对称）
let value = max(x, y, z)  // 另一个感到自然的自由函数

resource.request().onComplete { [weak self] response in
  guard let strongSelf = self else {
    return
  }
  let model = strongSelf.updateModel(response)
  strongSelf.updateUI(model)
}

// 如果在响应返回前 self 被释放，则可能导致崩溃
resource.request().onComplete { [unowned self] response in
  let model = self.updateModel(response)
  self.updateUI(model)
}

// 内存回收可以发生在更新模型和更新 UI 之间
resource.request().onComplete { [weak self] response in
  let model = self?.updateModel(response)
  self?.updateUI(model)
}

private let message = "Great Scott!"

class TimeMachine {  
  fileprivate dynamic lazy var fluxCapacitor = FluxCapacitor()
}

fileprivate let message = "Great Scott!"

class TimeMachine {  
  lazy dynamic fileprivate var fluxCapacitor = FluxCapacitor()
}

for _ in 0..<3 {
  print("Hello three times")
}

for (index, person) in attendeeList.enumerated() {
  print("\(person) is at position #\(index)")
}

for index in stride(from: 0, to: items.count, by: 2) {
  print(index)
}

for index in (0...3).reversed() {
  print(index)
}

var i = 0
while i < 3 {
  print("Hello three times")
  i += 1
}

var i = 0
while i < attendeeList.count {
  let person = attendeeList[i]
  print("\(person) is at position #\(i)")
  i += 1
}

func computeFFT(context: Context?, inputData: InputData?) throws -> Frequencies {

  guard let context = context else {
    throw FFTError.noContext
  }
  guard let inputData = inputData else {
    throw FFTError.noInputData
  }

  // 用上下文和输入计算频率
  return frequencies
}

func computeFFT(context: Context?, inputData: InputData?) throws -> Frequencies {

  if let context = context {
    if let inputData = inputData {
      // 用上下文和输入计算频率

      return frequencies
    } else {
      throw FFTError.noInputData
    }
  } else {
    throw FFTError.noContext
  }
}

guard let number1 = number1,
      let number2 = number2,
      let number3 = number3 else {
  fatalError("impossible")
}
// 用数字做某事

if let number1 = number1 {
  if let number2 = number2 {
    if let number3 = number3 {
      // 用数字做某事
    } else {
      fatalError("impossible")
    }
  } else {
    fatalError("impossible")
  }
} else {
  fatalError("impossible")
}

let swift = "not a scripting language"

let swift = "not a scripting language";

if name == "Hello" {
  print("World")
}

if (name == "Hello") {
  print("World")
}

let playerMark = (player == current ? "X" : "O")