swift - 可解码符合枚举类型的属性

Question

我有这个枚举:

enum DealStatus:String {
    case PENDING = "Pending"
    case ACTIVE = "Active"
    case STOP = "Stop"
    case DECLINED = "Declined"
    case PAUSED = "Paused"
}

和结构:

struct ActiveDeals: Decodable {
    let keyword:            String
    let bookingType:        String
    let expiryDate:         Int
    let createdAt:          Int?
    let shopLocation:       String?
    let dealImages:         [DealImages]?
    let dealStatus:         String?
    let startingDate:       Int?
}

在结构中，我试图将枚举分配为 dealStatus 的类型，如下所示:

struct ActiveDeals: Decodable {
        let keyword:            String
        let bookingType:        String
        let expiryDate:         Int
        let createdAt:          Int?
        let shopLocation:       String?
        let dealImages:         [DealImages]?
        let dealStatus:         DealStatus
        let startingDate:       Int?
    }

但是我遇到了一些编译器错误:

Type 'ActiveDeals' does not conform to protocol 'Decodable'

Protocol requires initializer 'init(from:)' with type 'Decodable'(Swift.Decodable)

Cannot automatically synthesize 'Decodable'because 'DealStatus' does not conform to 'Decodable'

Answer 1

问题是 Swift 可以自动合成 Decodable 所需的方法，只有当一个结构的所有属性也是 Decodable 而你的枚举不是 Decodable 。

刚刚在 playground 上试了一下，似乎你可以让你的枚举 Decodable 只需声明它是，Swift 会自动为你合成这些方法。即

enum DealStatus:String, Decodable  
//                      ^^^^^^^^^ This is all you need
{
    case PENDING = "Pending"
    case ACTIVE = "Active"
    case STOP = "Stop"
    case DECLINED = "Declined"
    case PAUSED = "Paused"
}