ios - 使用Swift解析嵌套JSON数据的正确方法是什么？

Question

我是Swift和iOS开发的新手，目前正在学习如何使用JSON数据。

我正在尝试解析嵌套的JSON数据并显示以下输出:

White hex value is #ffffff
Black hex value is #000000
Gray10 hex value is #f5f7f8
Gray20 hex value is #e8eced
Gray30 hex value is #d5d9db
Gray40 hex value is #b6bec2
Gray50 hex value is #8e999e
Gray60 hex value is #69757a
Gray70 hex value is #495257
Gray80 hex value is #333a3d
Gray90 hex value is #1f2426
Purple10 hex value is #ffc7f2
Purple20 hex value is #f59de2
Purple30 hex value is #e07ecb
Purple40 hex value is #d160b7
Purple50 hex value is #b34fa0
Purple60 hex value is #964286
Purple70 hex value is #773569
Purple80 hex value is #5b284f
Purple90 hex value is #401c36

我能够解析一个简单的JSON文件，例如:

{
  "color": {
    "white": { "value": "#fff" },
    "black": { "value": "#000" }
  }
}

但是，我无法弄清楚如何正确地将嵌套数据(如下所示)解码为structs，并将gray和purple 键与它们的数字intensity 键(10-90)连接起来，如上面所需的输出所示。

这是我的带有嵌套JSON数据的操场代码无法正常工作:

import Foundation

let json = """
{
  "color": {
    "white": { "value": "#fff" },
    "black": { "value": "#000" },
    "gray": {
      "10": { "value": "#f5f7f8" },
      "20": { "value": "#e8eced" },
      "30": { "value": "#d5d9db" },
      "40": { "value": "#b6bec2" },
      "50": { "value": "#8e999e" },
      "60": { "value": "#69757a" },
      "70": { "value": "#495257" },
      "80": { "value": "#333a3d" },
      "90": { "value": "#1f2426" }
    },
    "purple": {
      "10": { "value": "#ffc7f2" },
      "20": { "value": "#f59de2" },
      "30": { "value": "#e07ecb" },
      "40": { "value": "#d160b7" },
      "50": { "value": "#b34fa0" },
      "60": { "value": "#964286" },
      "70": { "value": "#773569" },
      "80": { "value": "#5b284f" },
      "90": { "value": "#401c36" }
    }
  }
}
""".data(using: .utf8)!

struct color: Codable {
  let value: String
  struct intensity {
    let value: String
  }
}

struct Entry: Codable {
  let color: [String: color]
}

let jsonDecoder = JSONDecoder()

do {
  let parsedJSON = try jsonDecoder.decode(Entry.self, from: json)
  for color in parsedJSON.color {
    print("\(color.key) hex value is \(color.value.value)")
  }
}

最终，此功能将最终出现在iOS应用中。

上面的代码中显示的(部分)JSON数据是实际生产数据。它以这种格式提供给我。因此，我无法更改JSON数据的定义或嵌套方式。

我将对如何解析嵌套的JSON数据并显示如上所示的数据提供一些指导。

Answer 1

除非您知道颜色名称是什么，否则您将无法使用Codable。但是，您可以使用一些自定义解码逻辑来创建从上面的json定义的结构数组。示例游乐场代码可能类似于以下代码。

import UIKit

struct MyColor {
    let name: String
    let value: String

    var console: String {
        return name + " hex value is " + value
    }
}

let json = "{\"color\":{\"white\":{\"value\":\"#fff\"},\"black\":{\"value\":\"#000\"},\"gray\":{\"10\":{\"value\":\"#f5f7f8\"},\"20\":{\"value\":\"#e8eced\"},\"30\":{\"value\":\"#d5d9db\"},\"40\":{\"value\":\"#b6bec2\"},\"50\":{\"value\":\"#8e999e\"},\"60\":{\"value\":\"#69757a\"},\"70\":{\"value\":\"#495257\"},\"80\":{\"value\":\"#333a3d\"},\"90\":{\"value\":\"#1f2426\"}},\"purple\":{\"10\":{\"value\":\"#ffc7f2\"},\"20\":{\"value\":\"#f59de2\"},\"30\":{\"value\":\"#e07ecb\"},\"40\":{\"value\":\"#d160b7\"},\"50\":{\"value\":\"#b34fa0\"},\"60\":{\"value\":\"#964286\"},\"70\":{\"value\":\"#773569\"},\"80\":{\"value\":\"#5b284f\"},\"90\":{\"value\":\"#401c36\"}}}}"

func parse() throws -> [MyColor] {
    var myColors: [MyColor] = []
    if let data = json.data(using: .utf8) {
        if let root = try JSONSerialization.jsonObject(with: data, options: .allowFragments) as? [String:Any] {
            if let colors = root["color"] as? [String:Any] {
                for color in colors.keys {
                    if let valueNode = colors[color] as? [String:String] {
                        if let value = valueNode["value"] {
                            myColors.append(MyColor(name: color, value: value))
                        }
                    } else if let variants = colors[color] as? [String:[String:String]] {
                        for key in variants.keys {
                            if let variant = variants[key] {
                                if let value = variant["value"] {
                                    myColors.append(MyColor(name: color + key, value: value))
                                }
                            }
                        }
                    }
                }
            }
        }
    }
    return myColors
}

if let colors = try? parse() {
    for color in colors {
        print(color.console)
    }
}

希望能帮助到你。