ios - 单个 JSON 返回的多个可编码对象类型

Question

我的困境是我在 JSON 响应中从一个表中接收到两种不同的对象类型。这是返回中两种类型的响应示例。

"supplementaryItems": [
    {
        "header": "Doodle",
        "subHeader": "It's a drawing.",
        "slideID": 4,
        "imageName": null,
        "textItems": null,
        "sortOrder": 0
    },
    {
        "header": "Cell Phones",
        "subHeader": "No phones please",
        "slideID": 8,
        "imageName": "welcome_icon_cellphones",
        "textItems": ["first","second","third"],
        "sortOrder": 1
    }
]

我们希望在这里创建两种不同类型的对象。一个 textOnlyItem 和一个 imageWithTextItem。

有没有一种方法可以创建一个子类或扩展，可以通过 imageName 是否为 null 定义的 Bool 键控还是不是？

感谢大家的帮助。

Answer 1

您不需要两个不同的对象。只需将 imageName 和 textItems 声明为可选，这将处理 null 情况。

您可以简单地检查imageName是否为nil

let jsonString = """
{"supplementaryItems": [
{
"header": "Doodle",
"subHeader": "It's a drawing.",
"slideID": 4,
"imageName": null,
"textItems": null,
"sortOrder": 0
},
{
"header": "Cell Phones",
"subHeader": "No phones please",
"slideID": 8,
"imageName": "welcome_icon_cellphones",
"textItems": ["first","second","third"],
"sortOrder": 1
}
]
}
"""

---

struct Root : Decodable {
    let supplementaryItems : [SupplementaryItem]
}

struct SupplementaryItem : Decodable {
    let header : String
    let subHeader : String
    let slideID : Int
    let imageName : String?
    let textItems : [String]?
    let sortOrder : Int
}

do {
    let data = Data(jsonString.utf8)
    let result = try JSONDecoder().decode(Root.self, from: data)
    for item in result.supplementaryItems {
       if let imageName = item.imageName {
           print(imageName + " has text items")
       } else {
           print(item.header + " has no text items")
       }
    }
} catch { print(error) }