我生成了以下JSON示例块。任何以字母结尾的值都是动态的。
{
"groupName": {
"groupA": {
"fields": {
"fieldA": "valueA",
"fieldB": "valueB"
},
"letters": {
"letterA: "A"
}
},
"groupB": {
"fields": {
"fieldC": "valueC",
"fieldD": "valueD"
},
"letters": {
"letterB: "B"
}
}
}
}
我的目标是使用Decodable
,以便可以将此数据读入已定义的struct
s中。
以下是我目前在游乐场文件中包含的工作,我正在使用这些文件来尝试解决此问题:
import Foundation
let jsonString = "{\"groupName\":{\"groupA\":{\"fields\":{\"fieldA\":\"valueA\",\"fieldB\":\"valueB\"},\"letters\":{\"letterA:\"A\"}},\"groupB\":{\"fields\":{\"fieldC\":\"valueC\",\"fieldD\":\"valueD\"},\"letters\":{\"letterB:\"B\"}}}}"
struct CustomCodingKeys: CodingKey {
var intValue: Int?
var stringValue: String
init?(intValue: Int) { self.intValue = intValue; self.stringValue = "\(intValue)" }
init?(stringValue: String) { self.stringValue = stringValue }
static let field = CustomCodingKeys.make(key: "field")
static func make(key: String) -> CustomCodingKeys {
return CustomCodingKeys(stringValue: key)!
}
}
// Values
struct Field {
let field: String
let value: String
}
struct Letter: Decodable {
let title: String
let letter: String
}
// Value holders
struct FieldData: Decodable {
var fields: [Field]
init(from decoder: Decoder) throws {
self.fields = [Field]()
let container = try decoder.container(keyedBy: CustomCodingKeys.self)
for key in container.allKeys {
print("processing field: \(key.stringValue)")
let dynamicKey = CustomCodingKeys.make(key: key.stringValue)
let value = try container.decode(String.self, forKey: dynamicKey)
let field = Field(field: key.stringValue,
value: value)
fields.append(field)
}
}
}
struct LetterData: Decodable {
var letters: [Letter]
init(from decoder: Decoder) throws {
self.letters = [Letter]()
let container = try decoder.container(keyedBy: CustomCodingKeys.self)
for key in container.allKeys {
print("processing letter: \(key.stringValue)")
let dynamicKey = CustomCodingKeys.make(key: key.stringValue)
let value = try container.decode(String.self, forKey: dynamicKey)
let letter = Letter(title: key.stringValue,
letter: value)
letters.append(letter)
}
}
}
// Containers
struct Group: Decodable {
var name: String!
var groups: [GroupData]
init(from decoder: Decoder) throws {
self.groups = [GroupData]()
let container = try decoder.container(keyedBy: CustomCodingKeys.self)
for key in container.allKeys {
print("processing section: \(key.stringValue)")
let group = try container.decode(GroupData.self,
forKey: key)
groups.append(group)
}
}
}
struct GroupData: Decodable {
var fieldData: FieldData
var letterData: LetterData
enum CodingKeys: String, CodingKey {
case fieldData = "fields"
case letterData = "letters"
}
}
struct GroupList: Decodable {
struct GroupName: Decodable {
var name: String!
var groups: [Group]
init(from decoder: Decoder) throws {
self.groups = [Group]()
let container = try decoder.container(keyedBy: CustomCodingKeys.self)
for key in container.allKeys {
let name = key.stringValue
self.name = name
print("processing group: \(String(describing: self.name))")
var group = try container.decode(Group.self,
forKey: key)
group.name = name
groups.append(group)
}
}
}
let groupName: GroupName
}
let decoder = JSONDecoder()
if let data = jsonString.data(using: .utf8),
let groupList = try? decoder.decode(GroupList.self,
from: data) {
print("group list created")
}
在我的GroupData
结构中,我可以删除变量,然后实现init(from decoder: Decoder) throws
,当使用正确的查询(FieldData和LetterData初始化)进行配置时,它可以标识正确的对。但是,它没有填充适当的值结构。
答案 0 :(得分:1)
您在解码Group
时犯了一个小错误。您倾向于对Group
内部的组的所有密钥进行解码,并且还进一步传递对其本身具有“字段”和“字母”的GroupData
进行解码。在Group
内使用单一值容器,应该没问题。
Group
的外观如下,
struct Group: Decodable {
var name: String!
var groups: GroupData
init(from decoder: Decoder) throws {
let container = try decoder.singleValueContainer()
groups = try container.decode(GroupData.self)
}
}
请注意,您的json本身不正确,我已经对其进行了格式化,而它应该像这样,
let jsonString = "{\"groupName\":{\"groupA\":{\"fields\":{\"fieldA\":\"valueA\",\"fieldB\":\"valueB\"},\"letters\":{\"letterA\":\"A\"}},\"groupB\":{\"fields\":{\"fieldC\":\"valueC\",\"fieldD\":\"valueD\"},\"letters\":{\"letterB\":\"B\"}}}}"
答案 1 :(得分:-1)
我使用这个https://app.quicktype.io/来帮助我转换它们。 我检查了您的输出,这在行上是错误的:
"letters": {
"letterA: "A"
}
正确的:
"letterA": "A"
在字母B中出现相同的字母。
正确检查输出:
{
"groupName": {
"groupA": {
"fields": {
"fieldA": "valueA",
"fieldB": "valueB"
},
"letters": {
"letterA": "A"
}
},
"groupB": {
"fields": {
"fieldC": "valueC",
"fieldD": "valueD"
},
"letters": {
"letterB": "B"
}
}
}
}