“应解码 Dictionary<String, Any> 但找到了一个数组。”，underlyingError: nil))答案

【问题标题】："Expected to decode Dictionary<String, Any> but found an array instead.", underlyingError: nil))“应解码 Dictionary<String, Any> 但找到了一个数组。”，underlyingError: nil))
【发布时间】：2020-06-03 02:36:14
【问题描述】：

我的 User 结构是这样声明的。我们如何使用JSONdecoder 解码数组？

我收到 typeMismatch(Swift.Dictionary<Swift.String, Any>, Swift.DecodingError.Context(codingPath: [], debugDescription: "Expected to decode Dictionary<String, Any> but found an array instead.", underlyingError: nil))

的错误

This is my json data:

// http://localhost:1337/user/5eca2fa01583786f1c0ee1bc

[
  {
    "id": "5eca2fa01583786f1c0ee1bc",
    "fullName": "Raj Shrestha",
    "emailAddress": "raj@yahoo.com",
    "following": [

    ],
    "followers": [
      {
        "id": "5eca2f451583786f1c0ee1ba",
        "fullName": "Udin Rajkarnikar",
        "emailAddress": "udin@gmail.com"
      }
    ],
    "isFollowing": true
  },
  [
    {
      "createdAt": 1590581837003,
      "updatedAt": 1590581837003,
      "id": "5ece5a4d6e2e801e95365d50",
      "text": "I love waterfalls",
      "imageUrl": "https://nepgram-bucket.s3.amazonaws.com/a121f7-6854-4fe9-bc8e-defce029d",
      "user": {
        "id": "5eca2fa01583786f1c0ee1bc",
        "fullName": "Raj Shrestha",
        "emailAddress": "raj@yahoo.com"
      }
    },
    {
      "createdAt": 1590334928984,
      "updatedAt": 1590334928984,
      "id": "5eca95d08538288438c63779",
      "text": "Creating post from iphone",
      "imageUrl": "https://nepgram-bucket.s3.amazonaws.com/2badfb0e-de49-4b6c-ae1-0c6",
      "user": {
        "id": "5eca2fa01583786f1c0ee1bc",
        "fullName": "Raj Shrestha",
        "emailAddress": "raj@yahoo.com"
      }
    },
    {
      "createdAt": 1590308888243,
      "updatedAt": 1590308888243,
      "id": "5eca30181583786f1c0ee1bf",
      "text": "asdasd",
      "imageUrl": "https://nepgram-bucket.s3.ap-south-1.amazonaws.com/83b7e688b-4d37-a368-3b8b4526bd58.png",
      "user": {
        "id": "5eca2fa01583786f1c0ee1bc",
        "fullName": "Raj Shrestha",
        "emailAddress": "raj@yahoo.com"
      }
    }
  ]
]

struct User: Decodable {
    let id : String
    let fullName: String
    let emailAddress: String
    var isFollowing: Bool?
    var followers, following: [User]?
    var post: [Post]? 
}

struct Post: Decodable { 
    let id: String
    let createdAt: Int
    let text: String
    let user: User
    let imageUrl: String
}

let user = try JSONDecoder().decode([User].self, from: data)

print(user)

【问题讨论】：

你能添加你试图解码的 JSON 对象吗？
我已经添加了 JSON 文件。
JSON 与模型不匹配。没有键 post 并且将异构数组作为根对象无论如何都是一个坏主意。
我认为问题在于您的 JSON 无效，根是数组，模型与 JSON 不匹配。
我发现了问题。谢谢大家！

标签： ios swift

【解决方案1】：

需要查看 JSON，但这里的一个明显错误可能是您的 json 是一个用户数组，在这种情况下您需要以下内容：

let users = try JSONDecoder().decode([User].self, from: data)

【讨论】：

【解决方案2】：

你可以这样做

import Foundation

struct UserUnion: Codable {
    let fluffyUser:FluffyUser
    let purpleUserArray:[PurpleUser]
}

// MARK: - PurpleUser
struct PurpleUser: Codable {
    let createdAt, updatedAt: Int
    let id, text: String
    let imageURL: String
    let user: UserElement
}

// MARK: - UserElement
struct UserElement: Codable {
    let id, fullName, emailAddress: String
}

// MARK: - FluffyUser
struct FluffyUser: Codable {
    let id, fullName, emailAddress: String
    let following: [UserElement]?
    let followers: [UserElement]
    let isFollowing: Bool
}

let userUnion = try JSONDecoder().decode([UserUnion].self, from: data)

print(userUnion)

【讨论】：