在Swift 4.2中解析JSON数据时出现typeMismatch错误

问题描述 投票:-1回答:1

类型不匹配错误 - 期望解码数组但找到字典。我正在使用嵌入代码中的本地json文件。 Json文件包含有关包的信息。我需要选择值并相应地显示到tableview控制器中。请在可编码模型或代码中确定我做错了什么。 JSON解析未正确处理。

文件格式:

{
  "packages": [
    {
      "name": "Platinum Maksi 6 GB",
      "desc": "Zengin içerikli Platinum Maksi Paketi ile Turkcell Uygulamalarının keyfini sürün!",
      "subscriptionType": "monthly",
      "didUseBefore": true,
      "benefits": [
        "TV+",
        "Fizy",
        "BiP",
        "lifebox",
        "Platinum",
        "Dergilik"
      ],
      "price": 109.90,
      "tariff": {
        "data": "6144",
        "talk": "2000",
        "sms": "100"
      },
      "availableUntil": "1558131150"
    }
]
}

型号:基本型号

struct Base : Codable {

    let packages : [Package]?

    enum CodingKeys: String, CodingKey {
            case packages = "packages"
    }

    init(from decoder: Decoder) throws {
            let values = try decoder.container(keyedBy: CodingKeys.self)
            packages = try values.decodeIfPresent([Package].self, forKey: .packages)
    }

2)包装型号:

struct Package : Codable {

    let availableUntil : String?
    let benefits : String?
    let desc : String?
    let didUseBefore : Bool?
    let name : String?
    let price : Int?
    let subscriptionType : String?
    let tariff : Tariff?

    enum CodingKeys: String, CodingKey {
            case availableUntil = "availableUntil"
            case benefits = "benefits"
            case desc = "desc"
            case didUseBefore = "didUseBefore"
            case name = "name"
            case price = "price"
            case subscriptionType = "subscriptionType"
            case tariff = "tariff"
    }

    init(from decoder: Decoder) throws {
            let values = try decoder.container(keyedBy: CodingKeys.self)
            availableUntil = try values.decodeIfPresent(String.self, forKey: .availableUntil)
            benefits = try values.decodeIfPresent(String.self, forKey: .benefits)
            desc = try values.decodeIfPresent(String.self, forKey: .desc)
            didUseBefore = try values.decodeIfPresent(Bool.self, forKey: .didUseBefore)
            name = try values.decodeIfPresent(String.self, forKey: .name)
            price = try values.decodeIfPresent(Int.self, forKey: .price)
            subscriptionType = try values.decodeIfPresent(String.self, forKey: .subscriptionType)
            tariff = try Tariff(from: decoder)
    }

}

关税模式:

struct Tariff : Codable {

    let data : String?
    let sms : String?
    let talk : String?

    enum CodingKeys: String, CodingKey {
            case data = "data"
            case sms = "sms"
            case talk = "talk"
    }

    init(from decoder: Decoder) throws {
            let values = try decoder.container(keyedBy: CodingKeys.self)
            data = try values.decodeIfPresent(String.self, forKey: .data)
            sms = try values.decodeIfPresent(String.self, forKey: .sms)
            talk = try values.decodeIfPresent(String.self, forKey: .talk)
    }

}

我的代码:

var pack = [Package]()

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view.

    let url = Bundle.main.url(forResource: "packageList", withExtension: "json")!
    do {
        let data = try Data(contentsOf: url)
        pack = try JSONDecoder().decode([Package].self, from: data)
        print(pack)

    } catch {
        print(error)
    }
arrays json swift
1个回答
0
投票

您正在解码错误的对象。您必须始终解码JSON的根对象Base

Package获取base.packages数组

let base = try JSONDecoder().decode(Base.self, from: data)
pack = base.packages

现在你将得到另外两种类型的不匹配错误,将benefits的类型更改为[String],将price更改为Double

您可以显着减少结构:删除所有CodingKeys和所有初始化程序,并将所有结构成员声明为非可选(删除问号)。

编辑:

解码availableUntil作为Date声明它为Date

let availableUntil: Date

并添加自定义日期解码策略,因为该值是一个字符串(如果值为Int会更容易)

let decoder = JSONDecoder()
decoder.dateDecodingStrategy = .custom{ decoder -> Date in
    let container = try decoder.singleValueContainer()
    let dateStr = try container.decode(String.self)
    guard let interval = TimeInterval(dateStr) else { throw DecodingError.dataCorruptedError(in: container, debugDescription: "Date string cannot be converted to TimeInterval") }
    return Date(timeIntervalSince1970: interval)
}
let data = try Data(contentsOf: url)
let base = try decoder.decode(Base.self, from: data)
pack = base.packages
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