iOS二次发育（swift）类

类的初探

class Person{
    var firstName: String
    var lastName: String
    init(firstName:String, lastName:String) {
        self.firstName = firstName
        self.lastName = lastName
    }
    func out() -> String {
        return self.firstName + self.lastName
    }
    func goEast() {
        self.firstName += "aaa"
    }
}

let person = Person(firstName: "1", lastName: "2")
person.out()
person.firstName = "3";
let person2 = person
person2.goEast()
person2.out()

person === person2/*引用同一块地址*/

struct Location{
    var x = 0.0
    var y = 0.0
    func out() -> Float {
        return Float(x + y);
    }
    
}

//值类型 方法改变自身，需声明关键字mutating
//结构体
struct Location2{
    var x = 0
    var y = 0
    mutating func goEast() {
        self.x += 1
    }
}

//枚举
enum Switch{
    case On
    case Off
    mutating func click() {
        switch self {
        case .On:
            self = .Off
        case .Off:
            self = .On
        }
    }
}

var button = Switch.Off
button.click()

 

//方法
struct Point{
    var x:Float = 0
    var y:Float = 0
}
struct Size{
    var width:Float = 0
    var height:Float = 0
}
class Rectangle{
    var point:Point
    var size:Size
    init(point:Point, size:Size) {
        self.point = point
        self.size = size
    }
    //计算型属性
    var center:Point{
        get{
            let x = self.point.x + self.size.width/2.0
            let y = self.point.y + self.size.height/2.0
            let point = Point(x: x, y: y)
            return point
        }set{
            let x = newValue.x - self.size.width/2.0
            let y = newValue.y - self.size.height/2.0
            self.point = Point(x: x, y: y)
        }
    }
}

let rectangle = Rectangle(point: Point(x:10, y:20), size: Size(width: 20, height: 20))
rectangle.center
rectangle.center = Point(x: 1, y: 1)
rectangle.point

CGRect(x: 0, y: 0, width: 1, height: 1)

Int.max
Int.min
//类方法
struct Matrix {
    var m: [[Int]]
    var row: Int
    var col: Int
    init? ( _ arr2d: [[Int]] ) {
        guard arr2d.count > 0 else {
            return nil
        }
        let row = arr2d.count
        let col = arr2d[0].count
        for i in 1..<row {
            if arr2d[i].count != col{
                return nil
            }
        }
        self.m = arr2d
        self.row = row
        self.col = col
    }
    func printMatrix() {
        for i in 0..<self.row {
            for j in 0..<self.col {
                print(self.m[i][j], terminator: "\t")
            }
            print()
        }
    }
    static func identityMatrix(n: Int) -> Matrix? {
        if n <= 0 {
            return nil
        }
        var arr2d: [[Int]] = []
        for i in 0..<n {
            var row = [Int](repeating: 0, count: n)
            row[i] = 1
            arr2d.append(row)
        }
        return Matrix(arr2d)
    }
}
if let m = Matrix([[1, 2], [3,4]]) {
    m.printMatrix()
}
if let m2 = Matrix .identityMatrix(n: 4) {
    m2.printMatrix()
}

//property observer 属性观察器
class LightBulb {
    static let maxCurrent = 30
    var current = 0 {
//        willSet{
//            print(newValue)
//        }
        didSet {
            if self.current >= LightBulb.maxCurrent {
                print("错误\(oldValue)")
            }
        }
    }
}

let lightBulb = LightBulb()
lightBulb.current = 10
lightBulb.current = 40

 类的继承

//类方法用static关键字，无法继承，所以要用class关键字
class Math{
    class func abs(number: Int) -> Int {
        if number < 0 {
            return (-number)
        } else {
            return number
        }
    }
}
Math.abs(number: -35)

class SubMatn: Math {
    override class func abs(number: Int) -> Int {
        return super.abs(number: number)
    }
}