Swift|Swift 枚举 Swift枚举

enum ApiType { case home case userInfo(userId:String) }var apiType = ApiType.userInfo(userId: "12345")if case let ApiType.userInfo(userId) = apiType { // "12345" print(userId) }apiType = ApiType.homeif case ApiType.home = apiType { // "ApiType.home" print("ApiType.home") }switch apiType { case .home: print("home") case .userInfo("12345"): print("userInfo(\"12345\")") case let .userInfo(userId): print("userInfo \(userId)") }

注意case和case let,如果只想处理部分情况，可以考虑使用 if case进行匹配，而不需要写switch。
rawValue
枚举类型和基础类型进行比较时，可以考虑使用 rawValue。

enum Direction : Int { // e = 0 case e case s = 3 // w = 4 case w case n = 9 }enum Name : String { case Tom case Tony = "122" // Ted = "Ted" case Ted }

RawRepresentable
【Swift|Swift 枚举】在声明枚举的时候，可以选择遵循 RawRepresentable 协议。

public protocol RawRepresentable { // 被associatedtype关键字修饰的变量，具体的类型需要让实现的类来指定 associatedtype RawValueinit?(rawValue: Self.RawValue)var rawValue: Self.RawValue { get } }// ExpressibleByStringLiteral // struct MyApi : Equatable,ExpressibleByStringLiteral { var url : String?static func == (obj1:MyApi,obj2:MyApi) -> Bool { if obj1.url == nil && obj2.url == nil { return true }if obj1.url == nil || obj2.url == nil { return false }if obj1.url!.elementsEqual(obj2.url!) { return true } else { return false } }init(stringLiteral value: StringLiteralType) { self.url = value } }enum MyApiEnum : MyApi,RawRepresentable { typealias RawValue = https://www.it610.com/article/MyApicase home, detail case unknown// Enum with raw type cannot have cases with arguments // case userInfo(userId:String)var rawValue: RawValue { switch self { case .home: return MyApi("123") case .detail: return MyApi("234") default: return MyApi("xxxx") } }init?(rawValue: MyApi) { switch rawValue { case MyApi("123") : self = MyApiEnum.home case MyApi("234") : self = MyApiEnum.detail default: self = MyApiEnum.unknown } } }let kk = MyApiEnum.detail.rawValue// MyApi(url: Optional("234")) print(kk)