不错的参考: Enum进阶

使用enum创建枚举，像类和其他所有类型那样，枚举可以有方法，供访问。

//  ViewController.swift
//  Swift枚举和结构体
//
//  Created by Hunter on 20/01/2017.
//  Copyright © 2017 Hunter. All rights reserved.
//

import UIKit

private enum Suit {
    case spades, hearts, diamonds, clubs
    func simpleDescription() -> String {
        switch self {
        case .spades:
            return "spades,简单描述--simpleDescription"
        case .hearts:
            return "hearts--simpleDescription"
        case .diamonds:
            return "diamonds--simpleDescription"
        case .clubs:
            return "clubs--simpleDescription"
        }
    }

    func color() -> UIColor {
        switch self {
        case .spades, .clubs:
            return UIColor.black
        case .diamonds, .hearts:
            return UIColor.red
        }
    }
}

private let hearts = Suit.hearts
private let heartsDescription = hearts.simpleDescription()

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        print(hearts,heartsDescription)
        view.backgroundColor = Suit.clubs.color()
        /*
         输出：hearts hearts--simpleDescription
         视图的背景颜色为黑色
         */
    }
}

再看一个枚举的简单使用

//
//  ViewController.swift
//  Swift枚举和结构体
//
//  Created by Hunter on 20/01/2017.
//  Copyright © 2017 Hunter. All rights reserved.
//

import UIKit

class ViewController: UIViewController {
    enum serverResponse {
        case result(String?, String?)
        case failure(String)

        func raw() -> AnyObject {
            switch self {
            case .result:
                return ("1", "2") as AnyObject
            case .failure:
                return ("3" as AnyObject)
            }
        }
    }

    let succes = serverResponse.result("日出时间: 8:00 AM", "日落时间: 19: 00 PM")
    let failure = serverResponse.failure("失败")

    override func viewDidLoad() {
        super.viewDidLoad()

        serverResponseTest()
        print(serverResponse.result(nil,nil).raw())
        /*
         输出:
         日出时间: 8:00 AM 日落时间: 19: 00 PM
         ("1", "2")
         */
    }

    func serverResponseTest() {
        switch succes {
        case let .result(sunrise, sunset):
            if let rise: String = sunrise, let set: String = sunset{
                print(rise, set)
            }
        case let .failure(message):
            print(message)
        }
    }

}

结构体同类很相似，它们最大的区别就是一个结构体传值，类传引用.

//  ViewController.swift
//  Swift枚举和结构体
//
//  Created by Hunter on 20/01/2017.
//  Copyright © 2017 Hunter. All rights reserved.
//

import UIKit

class ViewController: UIViewController {

    struct Person {
        var wife: String?
        var name: String
        var age: Int

        func who() -> String {
            return ("name:\(name),age:\(age)")
        }

    }

    let xiaoMing = Person.init(wife: nil, name: "小明", age: 28)

    override func viewDidLoad() {
        super.viewDidLoad()
        print(xiaoMing,xiaoMing.who())
    }

}