枚举的特殊用法

移动组周技术分享

枚举的特殊用法

源于项目中的应用太广了，但是对swift的很多简单特性不熟。之前那个动画的阶段使用到enum有遇到困难暂时绕开它了

当时的目标就是外部直接赋值操作

如下动画的enum示例：

为了省事，目前直接使用死的文案放在这里

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enum AnimationPeriod: UInt {
    // 动画执行的五个阶段
    case Start,First,Second,Third,End
    
    func description() -> String {
        switch self {
        case .Start, .First:    return "正在提取学校最新\n录取条件"
        case .Second:           return "正在与学校进行匹配"
        case .Third, .End:      return "正在根据匹配结果\n生成选校方案"
        }
    }
    
    func duration() -> NSTimeInterval {
        switch self {
        case .Start:    return 0.8
        case .First:    return 1
        case .Second:   return 2
        case .Third:    return 0.5
        case .End:      return 0.25
        }
    }
}
extension AnimationPeriod {
    mutating func next() {
        switch self {
        case .Start:    self = .First
        case .First:    self = .Second
        case .Second:   self = .Third
        case .Third:    self = .End
        default:        self = .End
        }
    }
}

下面我们看看一些枚举的使用

携带参数

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enum FamilyType {
    
    case Father(age: Int)
    case Mother(age: Int)
    case Sister(age: Int)
    func gift() -> String {
        switch(self) {
        case .Sister(let age):
            if age > 15 {
                return "iphone"
            } else {
                return "toy"
            }
        case .Mother(let age) where age < 40:
            return "cloth"
        default:
            return "book"
        }
    }
}
let someone = FamilyType.Sister(age: 11)
let somebody = FamilyType.Mother(age: 40)
// swift的枚举技巧
let someoneGift = someone.gift()     // print toy
let somebodyGift = somebody.gift()	 // book

####那我们要取值的有

  • 方法一
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switch someone {
case .Father(let age):
    age
case .Sister(let age):
    age
default:()
}
  • 方法二
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if case .Sister(let age) = someone {
    age
}

枚举的嵌套

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enum Colleague {
    enum Weight: Int {
        case Light
        case Mid
        case Heavy
    }
    case iOS(weight: Weight)
    case Android(weight: Weight)
    case HTML(weight: Weight)
}
let woodenHelmet = Colleague.iOS(weight: .Mid)

枚举的成员变量

之前就一直想要使用枚举做到外部动态对枚举赋值储存操作，
那成员变量用法如下

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// 根据自身赋值
enum Device {
    case iPad, iPhone
    var year: Int {
        switch self {
        case iPhone: return 2007
        case iPad: return 2010
        }
    }
}
// set get 方法对于枚举的成员变量是无效的，允许get调用但set不可执行
enum Book {
    case Story, News
    var year: Int {
        set{
            year = newValue
        }
        get{
            return self.year
        }
    }
}
let myIpad = Device.iPad
myIpad.year
var storyBook = Book.Story
//storyBook.year = 2010	 // set 方法此处报错
//storyBook.year			 // get 无效

初始化，感觉然并软

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enum AppleDevice {
    case iMac(price:Int)
    case iPod(price:Int)
    case iPhone(price:Int)
    init (costMoney: Int) {
        if costMoney > 10000 {
            self = .iMac(price: costMoney)
        } else if costMoney > 2500 {
            self = .iPhone(price: costMoney)
        } else {
            self = .iPod(price: costMoney)
        }
    }
}
let myDevice = AppleDevice(costMoney: 6000)

元组的使用

多个参数的介入时，可以使用元组,此处常规使用报错暂时无法解决，
使用func函数赋值倒是没有出错。why？？

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enum HumanHabit {
    case Reading
    case PlayGame
    case Traveling
}
typealias HumanInfo = (age: Int, name: String, habit: HumanHabit)
func selectRAM(humanInfo: HumanInfo) -> HumanInfo {return (age: 32, name: humanInfo.name, habit: humanInfo.habit)}
func selectCPU(humanInfo: HumanInfo) -> HumanInfo {return (age: humanInfo.age, name: "3.2GHZ", habit: humanInfo.habit)}
func selectGPU(humanInfo: HumanInfo) -> HumanInfo {return (age: humanInfo.age, name: "3.2GHZ", habit: .Reading)}
enum Desktop {
    case Cube(HumanInfo)
    case Tower(HumanInfo)
    case Rack(HumanInfo)
}
let aTower = Desktop.Tower(selectGPU(selectCPU(selectRAM((0, "", .Traveling) as HumanInfo))))