arrays - Swift 初始化空数组以稍后存储不同的结构

Question

我有几种不同类型的结构(促销和事件)。我想创建一个空数组，根据 if 语句的结果填充每种类型的数组。

所以像这样:

var dataArray:[Any] = []  // see options I've tried below 

if myTest == true {
    dataArray = [Promo, Promo, Promo]
} else {
    dataArray = [Event, Event, Event]    
}

我试过使用:

1. var dataArray: [Any] = []
2. var dataArray: [AnyObject] = []
3. var dataArray: [Any] = [Any]()
4. var dataArray: [AnyObject] = [AnyObject]()

但是当我尝试在 dataArray 中存储 Promo 结构数组时，出现错误 Cannot assign value of type '[Promo]' to type ' [任何]' 等

那么，我该如何初始化一个数组，以便它可以存储各种(未知的)结构。或者我如何修改我的 Structs 以使其能够存储在数组中？

我真的很难看到我做错了什么，所以任何指示都会很有帮助。

---

这是我的结构:Promo.swift

import Foundation

struct Promo {

    // initialise the stored properties for use later
    let promoId : Int
    let date : NSDate
    let title: String
    let body: String
    let busName : String
    let busId : Int
    let categoryId: Int
    let featured: Bool

    // a universal init() method which has optional parameters
    init(promoId: Int,
         date: NSDate,
         title: String,
         body: String,
         busName: String,
         busId: Int,
         categoryId: Int,
         featured: Bool
        ){
        self.promoId = promoId
        self.date = date
        self.title = title
        self.body = body
        self.busName = busName
        self.busId = busId
        self.categoryId = categoryId
        self.featured = featured
    }
}

// allow us to compare structs
extension Promo: Equatable {}
func ==(lhs: Promo, rhs: Promo) -> Bool {
    return lhs.promoId == rhs.promoId
        && lhs.date == rhs.date
        && lhs.title == rhs.title
        && lhs.body == rhs.body
        && lhs.busName == rhs.busName
        && lhs.busId == rhs.busId
        && lhs.categoryId == rhs.categoryId
        && lhs.featured == rhs.featured
}

Event.swift

import Foundation

struct Event {

    // initialise the stored properties for use later
    let eventId : Int
    let date : NSDate
    let title: String
    let body: String
    let busName : String
    let busId : Int
    let categoryId: Int

    // a universal init() method which has optional parameters
    init(eventId: Int,
         date: NSDate,
         title: String,
         body: String,
         busName: String,
         busId: Int,
         categoryId: Int
        ){
        self.eventId = eventId
        self.date = date
        self.title = title
        self.body = body
        self.busName = busName
        self.busId = busId
        self.categoryId = categoryId
    }
}

Answer 1

这可能不是您想要的，但是您可以通过使用类而不是结构来使它更清晰一些。看来“促销”只是一个带有一个额外数据成员(特色)的“事件”...如果是这样，那么您可以重命名 Promo.promoId 字段 Promo.eventId，然后使其成为事件的子类.像这样:

class Promo : Event {
    let featured: Bool

    // a universal init() method which has optional parameters
    init(eventId: Int,
         date: NSDate,
         title: String,
         body: String,
         busName: String,
         busId: Int,
         categoryId: Int,
         featured: Bool
        ){
        self.featured = featured
        super.init(eventId: eventId, date: date, title: title, body: body, busName: busName, busId: busId, categoryId: categoryId)
    }
}

然后像这样创建数据数组:

var dataArray = [Event]()

if myTest == true {
    dataArray = [promo1, promo2, promo3]
} else {
    dataArray = [event1, event2, event3]
}

要使用特色成员进行宣传，您仍然需要像这样转换:

if let thisPromo = dataArray[0] as? Promo {
    print(thisPromo.featured)
}