Question

我有一个struct类型，该类型列出了必须从JSON解码的不同类型，并且找不到关于如何在我的enum中称为CodingKeys的一种以上类型的信息。在最里面的字典中，有时一个key：value对将是[String:String]，而另一个key：value对将是[String:Int]

我尝试仅在下面的代码段中指定String和CodingKey，但是Xcode报告2条错误消息。

struct JSONSiteData : Codable {
    let destinationAddresses : [String]
    let originAddresses : [String]
    let rows : [    [String : [[String:[[String: [String:Any]]]]]]      ]
    let status : String
}

enum CodingKeys : String, CodingKey {
    case destinationAddresses = "destination_addresses"
    case originAddresses = "origin_addresses"
    case rows
    case status
}

我从Xcode收到以下错误消息；

Type 'JSONSiteData' does not conform to protocol 'Decodable'
Type 'JSONSiteData' does not conform to protocol 'Encodable'

这是我的JSON；

{
    "destination_addresses": [
        "1 Dunwell Ln, Bolam, Darlington DL2 2UW, UK",
        "Unnamed Road, Newton Aycliffe DL5 6QZ, UK",
        "Preston Manor Farm, Preston le Skerne, Newton Aycliffe DL5 6JH, United Kingdom",
        "6 Middridge Farms, Middridge, Newton Aycliffe DL5 7JQ, UK",
        "1 The Gardens, Hunwick, Crook DL15 0XW, UK"
    ],
    "origin_addresses": [
        "42 Drovers Way, Dunstable LU6 1AW, UK"
    ],
    "rows": [
        {
            "elements": [
                {
                    "distance": {
                        "text": "220 mi",
                        "value": 353731
                    },
                    "duration": {
                        "text": "3 hours 45 mins",
                        "value": 13475
                    },
                    "status": "OK"
                },
                {
                    "distance": {
                        "text": "222 mi",
                        "value": 356696
                    },
                    "duration": {
                        "text": "3 hours 45 mins",
                        "value": 13471
                    },
                    "status": "OK"
                },
                {
                    "distance": {
                        "text": "222 mi",
                        "value": 358053
                    },
                    "duration": {
                        "text": "3 hours 46 mins",
                        "value": 13545
                    },
                    "status": "OK"
                },
                {
                    "distance": {
                        "text": "225 mi",
                        "value": 361421
                    },
                    "duration": {
                        "text": "3 hours 49 mins",
                        "value": 13768
                    },
                    "status": "OK"
                },
                {
                    "distance": {
                        "text": "229 mi",
                        "value": 369280
                    },
                    "duration": {
                        "text": "3 hours 57 mins",
                        "value": 14238
                    },
                    "status": "OK"
                }
            ]
        }
    ],
    "status": "OK"
}

Answer 1

就Codable而言，没有不同的类型。

解码这些结构

struct JSONSiteData : Decodable {
    let destinationAddresses : [String]
    let originAddresses : [String]
    let rows : [Row]
    let status : String
}

struct Row : Decodable {
    let elements : [Element]
}

struct Element : Decodable {
    let distance : Item
    let duration : Item
    let status : String
}

struct Item : Decodable {
    let text : String
    let value : Int
}

Answer 2

您可以尝试一下，

// To parse the JSON, add this file to your project and do:
//
//   let jsonSiteData = try? newJSONDecoder().decode(JSONSiteData.self, from: jsonData)

import Foundation

struct JSONSiteData: Codable {
    let destinationAddresses, originAddresses: [String]
    let rows: [Row]
    let status: String

    enum CodingKeys: String, CodingKey {
        case destinationAddresses = "destination_addresses"
        case originAddresses = "origin_addresses"
        case rows, status
    }
}

struct Row: Codable {
    let elements: [Element]
}

struct Element: Codable {
    let distance, duration: Distance
    let status: String
}

struct Distance: Codable {
    let text: String
    let value: Int
}

请参考此链接以根据JSON字符串生成模型。 https://app.quicktype.io/

使用Codable时，如何在枚举CodingKeys中指定一种以上的类型进行解码？

2 个答案: