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swift 数据类型 class protocols Enumerations

admin 11月 12, 2020 0

struct Rectangle {
    //属性
    var width : Int
    var height : Int
}
var rectangle = Rectangle()
rectangle.height = 4

struct Rectangle {
    //属性
    var width : Int
    var height : Int
    var other : 12
    //初始化方法
    init(width: Int, height: Int) {
        self.width = width
        self.height = height
    }
    //函数
    func fitsInside(_ other: Rectangle) -> Bool {
        return (width < other.width) && (height < other.height)
    }
    //自动计算值
    var area: Int {
        return width * height
    }
}

Extensions

struct Rectangle {
    var width : Int
    var height : Int
    init(width: Int, height: Int) {
        self.width = width
        self.height = height
    }
}
extension Rectangle {
    func fitsInside(_ other: Rectangle) -> Bool {
        return (width < other.width) && (height < other.height)
    }
    var area: Int {
        return width * height
    }
}

泛型结构

struct NamedArray<Element> {
    var name: String
    var items: [Element]
}
//写法1
let boardGame :NamedArray<String> = NamedArray(name: "Board Games", items:["Chess", "Go"])
let primes: NamedArray<Int> = NamedArray(name: "Primes", items: [1,3,5,7,13])
//写法2 (推荐)
let boardGame = NamedArray(name: "Board Games", items:["Chess", "Go"])
let primes = NamedArray(name: "Primes", items: [1,3,5,7,13])

class

 class Fish {
    //属性
    var name: String
    //初始化
    init(name: String) {
        self.name = name
    }
    //方法
    func swim() {
        print("I'm swimming.")
    }
}
//继承
class FlyingFish: Fish {
    func fly() {
        print("fly")
    }
}
class ComplainingFish: Fish {
    var complaint: String
    //重写初始化方法
    init(name: String, complaint: String) {
        self.complaint = complaint
        super.init(name: name)
    }
    重写父类方法
    override func swim() {
        print("123")
        super.swim()
    }
}

protocols

protocol Player {
    func takeTurn(on board: Board)
}
struct HumanPlayer: Player {
    func takeTurn(on board: Board) {
   
    }
}
struct ComputerPlayer: Player {
    var name: String
    var score: Int
    func takeTurn(on board: Board) {
        
    }
}
let player1 = ComputerPlayer.init(name: "fuck", score: 1)
print(player1)
//使用 extension 关键字会打印相关信息
extension ComputerPlayer: CustomStringConvertible {
    var description: String {
        return "human player (name) has a score of (score)"
    }
}

Enumerations

enum Alignment {
    case left
    case right
}

等同于

1
2
3

enum Alignment {
    case left, right
}

1	let textAlignment = Alignment.left

switch textAlignment {
case Alignment.left:
    print("1")
case Alignment.right:
    print("2")
}

等同于

switch textAlignment {
case .left:
    print("12")
case .right:
    print("1")
}

其他用法

enum Alignment {
    case left(padding: Double), right(padding: Double), center
}
let textAlignment = Alignment.left(padding: 42.7)
switch textAlignment {
case .left(let padding):
    print("Left with (padding) pixels of padding")
case .right(let padding):
    print("Left with (padding) pixels of padding")
case .center:
    print("center")
}

enum ServerAddress: String {
    case google = "https://www.google.com"
    case apple = "https://www.apple.com"
}
func findAddress(matchingQuery: String, from server: ServerAddress) {
    let serviceAddress = server.rawValue
    print(serviceAddress)
    
}
findAddress(matchingQuery: "11", from: .google)

enum SomeError: ErrorProtocol {
    case somethingWentWrong, somethingFailed
}
func doSomething() throws -> Data {
    progressBar.visible = true
    defer { progressBar.visible = false }
    let data: Data?
    do {
        data = try somethingThatMightFail()
    } catch SomeError.somethingWentWrong {
        data = nil
    }
    guard let result = summarize(data) else { throw SomeError.somethingFailed }
    return result
}