ios - 从 Swift Decodables 访问枚举的合适方法是什么？

Question

我有一个非常奇怪的案例，我使用 JSON 并认为我可以一直子字符串化到我想要访问的数据，但是，它没有按预期工作。

使用 QuickType，我能够转换这个 JSON:https://kidsuper.fodalabs.com/wp-json/wp/v2/art

到下面。

尝试访问时，似乎我应该能够执行 .acf.gallery.id 但是一旦我到达 acf.gallery，它会显示 .id 不存在。这很奇怪，但这是我尝试时返回的内容

let temp = imageArray[indexPath.row].acf.gallery.id
Value of type 'GalleryUnion?' has no member 'id'

只是为了好玩，我尝试了这个，但也没有运气:

let temp = imageArray[indexPath.row].acf.GalleryUnion.galleryElementArray
    Error

: 'Acf' 类型的值没有成员 'GalleryUnion'

当我打印 .acf.gallery 时返回像这样开始:

Acf(company: "Season #3", 
     gallery: Optional(weddingszn.GalleryUnion.galleryElementArray([weddingszn.GalleryElement(
         id: 135, galleryID: 135, title: "1-791x1024", 
         filename: "1-791x1024.jpg", url: "https://kidsuper.fodalabs.com/wp-content/up

下面是我要解析的完整代码。有任何想法吗？

struct Acf: Codable {
    let company: String
    let gallery: GalleryUnion?
    let tagline: String
    let featuredImg: Bool?

    enum CodingKeys: String, CodingKey {
        case company, gallery, tagline
        case featuredImg = "featured_img"
    }
}

enum GalleryUnion: Codable {
    case bool(Bool)
    case galleryElementArray([GalleryElement])

    init(from decoder: Decoder) throws {
        let container = try decoder.singleValueContainer()
        if let x = try? container.decode(Bool.self) {
            self = .bool(x)
            return
        }
        if let x = try? container.decode([GalleryElement].self) {
            self = .galleryElementArray(x)
            return
        }
        throw DecodingError.typeMismatch(GalleryUnion.self, DecodingError.Context(codingPath: decoder.codingPath, debugDescription: "Wrong type for GalleryUnion"))
    }

    func encode(to encoder: Encoder) throws {
        var container = encoder.singleValueContainer()
        switch self {
        case .bool(let x):
            try container.encode(x)
        case .galleryElementArray(let x):
            try container.encode(x)
        }
    }
}

struct GalleryElement: Codable {
    let id, galleryID: Int
    let title, filename: String
    let url: String
    let alt, author, description, caption: String
    let name, date, modified: String
    let mimeType: MIMEType
    let type: TypeEnum
    let icon: String
    let width, height: Int
    let sizes: Sizes

    enum CodingKeys: String, CodingKey {
        case id = "ID"
        case galleryID = "id"
        case title, filename, url, alt, author, description, caption, name, date, modified
        case mimeType = "mime_type"
        case type, icon, width, height, sizes
    }
}

Answer 1

在向下钻取数组之前，您必须使用 if case、guard case 或 switch case 来解包枚举。

if case .galleryElementArray(let x) = imageArray[indexPath.row].acf.gallery {
    print(x.first!.id)
}