不同字典类型数组的快速编码

Question

我有JSON数据，它是一个字典数组，其中第一个项与其他数组项不同。

示例JSON

[
  {
    "totalDays": 180,
    "totalWorkingDays": 148,
    "totalWorkingHours": "1184:00:00",
    "totalWorkedHours": "985:23:10",
    "totalShortageHours": "-199:37:50",
    "avgWorkingHours": "06:39:28(83%)",
    "avgShortageHours": "01:20:31(17%)",
    "totalAbsents": 13,
    "totalLeaves": 4
  },
  {
    "attendanceDayCount": 1,
    "attendanceDate": "21-Jan-19",
    "attendanceDay": "Monday"
  },
  {
    "attendanceDayCount": 2,
    "attendanceDate": "22-Jan-19",
    "attendanceDay": "Tuesday"
  },
  {
    "attendanceDayCount": 3,
    "attendanceDate": "23-Jan-19",
    "attendanceDay": "Wednesday"
  }
]

我使用的是可编码的，我的结构看起来像这样

struct DashboardSummary : Codable {
    
   var totalDays : Int?
   var totalWorkingDays : Int?
   var totalWorkingHours : String?
   var totalWorkedHours : String?
   var totalShortageHours : String?
   var avgWorkingHours : String?
   var avgShortageHours : String?
   var totalAbsents : Int?
   var totalLeaves : Int?
   
} 

struct DaySummary : Codable {

   var attendanceDayCount : Int?
   var attendanceDate : String?
   var attendanceDay : String?    

}

编辑: JSON从网络请求方法解码

DispatchQueue.main.async {
   if let responseObject = try? JSONDecoder().decode(Response.self, from: data) {
     print("responseObject", responseObject)
     completion(.success(responseObject))
   }
   else {
     let error = NSError(domain: "", code: 200, userInfo: [NSLocalizedDescriptionKey : "Failed to decode"])
     completion(.failure(error))
   }
 }

Things我试过

1. I通过网络请求将'DashboardSummary‘结构作为可编码的结构传递给出了第一个项的结果，以及数组其余部分的零值。

。

1. I尝试了init(从解码器:解码器)和func编码(到编码器:编码器)，但不幸的是，init对我无效。

我怎么才能避开这一切？

Answer 1

首先，您需要创建第三个可以表示数组的结构，例如：

struct Response : Codable {
    var dashboardSummary: DashboardSummary?
    var daySummaries: [DaySummary]
    
    enum CodingKeys: CodingKey {
        case dashboardSummary, daySummaries
    }
}

然后，您需要实现init(from:)和encode(to:)来进行自定义编码。

您可以使用unkeyedContainer对其进行解码/编码。解码时，您继续从容器while解码容器--容器不是isAtEnd。

init(from decoder: Decoder) throws {
    var container = try decoder.unkeyedContainer()
    dashboardSummary = try container.decodeIfPresent(DashboardSummary.self)
    daySummaries = []
    while !container.isAtEnd {
        daySummaries.append(try container.decode(DaySummary.self))
    }
}

func encode(to encoder: Encoder) throws {
    var container = encoder.unkeyedContainer()
    try container.encode(dashboardSummary)
    for daySummary in daySummaries {
        try container.encode(daySummary)
    }
}

如果不打算更改属性，还可以考虑使属性let常量。