我有這個本地 JSON 檔案，其中包含標題、開始和結束。我想從開始和結束鍵創建日期，但是標題是一個字串，所以我可以創建事件物件。現在我已將所有內容解碼為字串。所以我正在嘗試創建一個自定義的 init，但是一個錯誤一直顯示“從初始化程式回傳而不初始化所有存盤的屬性”。不知道我做錯了什么
這是我的事件模型和我的 JSONFile
struct Event: Decodable & Equatable {
let title : String
let start : Date
let end : Date
//Custom decoding init
init(from decoder : Decoder) throws {
let container = try decoder.singleValueContainer()
let stringType = try container.decode(String.self)
switch stringType {
case "title":
self.title = try container.decode(String.self)
case "start":
self.start = try container.decode(Date.self)
case "end":
self.end = try container.decode(Date.self)
default:
throw DecodingError.dataCorruptedError(in: container, debugDescription: "Not valid date \(stringType)")
}
}
}
JSON
[{"title": "Evening Picnic", "start": "November 10, 2018 6:00 PM", "end": "November 10, 2018 7:00 PM"}, {"title": "Nap Break", "start": "November 8, 2018 12:30 PM", "end": "November 8, 2018 1:30 PM"}, {"title": "Football Game", "start": "November 3, 2018 6:00 PM", "end": "November 3, 2018 10:00 PM"}, {"title": "Evening Cookout with Friends", "start": "November 6, 2018 5:00 PM", "end": "November 6, 2018 10:00 PM"}, {"title": "Roller Derby", "start": "November 7, 2018 12:00 PM", "end": "November 7, 2018 2:30 PM"}, {"title": "Basketball Game", "start": "November 8, 2018 7:30 PM", "end": "November 8, 2018 10:30 PM"}, {"title": "Local Pub with Friends", "start": "November 1, 2018 7:30 PM", "end": "November 1, 2018 11:00 PM"}, {"title": "Dentist Appointment", "start": "November 10, 2018 1:45 PM", "end": "November 10, 2018 2:30 PM"}, {"title": "Free Donuts", "start": "November 9, 2018 3:00 PM", "end": "November 9, 2018 4:00 PM"}, {"title": "TV Show Marathon", "start": "November 9, 2018 4:30 PM", "end": "November 9, 2018 9:00 PM"}, {"title": "Lunch with Friends", "start": "November 8, 2018 11:30 AM", "end": "November 8, 2018 1:00 PM"}, {"title": "SF Coffee Festival","start": "November 6, 2018 6:00 PM","end": "November 6, 2018 9:00 PM"}, {"title": "Beer with Friends", "start": "November 9, 2018 8:00 PM", "end": "November 9, 2018 9:30 PM"}, {"title": "Yoga", "start": "November 1, 2018 6:00 PM", "end": "November 1, 2018 7:30 PM"}, {"title": "Rock Concert", "start": "November 7, 2018 6:30 PM", "end": "November 7, 2018 11:00 PM"}, {"title": "Lunch Meeting", "start": "November 9, 2018 12:30 PM", "end": "November 9, 2018 2:30 PM"}, {"title": "Bicycling with Friends", "start": "November 1, 2018 6:00 AM", "end": "November 1, 2018 9:30 AM"}, {"title": "Birthday Party", "start": "November 10, 2018 12:30 PM", "end": "November 10, 2018 8:30 PM"}, {"title": "Football Tailgate with John", "start": "November 3, 2018 6:00 PM", "end": "November 3, 2018 10:00 PM"}]
uj5u.com熱心網友回復：
沒有不同的型別，所有字典中的所有值都具有相同的型別String。
因此singleValueContainer是錯誤的方法，根本不需要自定義初始化程式。
解碼字串日期Date只需添加適當的日期解碼策略
let jsonString = """
[{"title": "Evening Picnic", "start": "November 10, 2018 6:00 PM", "end": "November 10, 2018 7:00 PM"}, {"title": "Nap Break", "start": "November 8, 2018 12:30 PM", "end": "November 8, 2018 1:30 PM"}, {"title": "Football Game", "start": "November 3, 2018 6:00 PM", "end": "November 3, 2018 10:00 PM"}, {"title": "Evening Cookout with Friends", "start": "November 6, 2018 5:00 PM", "end": "November 6, 2018 10:00 PM"}, {"title": "Roller Derby", "start": "November 7, 2018 12:00 PM", "end": "November 7, 2018 2:30 PM"}, {"title": "Basketball Game", "start": "November 8, 2018 7:30 PM", "end": "November 8, 2018 10:30 PM"}, {"title": "Local Pub with Friends", "start": "November 1, 2018 7:30 PM", "end": "November 1, 2018 11:00 PM"}, {"title": "Dentist Appointment", "start": "November 10, 2018 1:45 PM", "end": "November 10, 2018 2:30 PM"}, {"title": "Free Donuts", "start": "November 9, 2018 3:00 PM", "end": "November 9, 2018 4:00 PM"}, {"title": "TV Show Marathon", "start": "November 9, 2018 4:30 PM", "end": "November 9, 2018 9:00 PM"}, {"title": "Lunch with Friends", "start": "November 8, 2018 11:30 AM", "end": "November 8, 2018 1:00 PM"}, {"title": "SF Coffee Festival","start": "November 6, 2018 6:00 PM","end": "November 6, 2018 9:00 PM"}, {"title": "Beer with Friends", "start": "November 9, 2018 8:00 PM", "end": "November 9, 2018 9:30 PM"}, {"title": "Yoga", "start": "November 1, 2018 6:00 PM", "end": "November 1, 2018 7:30 PM"}, {"title": "Rock Concert", "start": "November 7, 2018 6:30 PM", "end": "November 7, 2018 11:00 PM"}, {"title": "Lunch Meeting", "start": "November 9, 2018 12:30 PM", "end": "November 9, 2018 2:30 PM"}, {"title": "Bicycling with Friends", "start": "November 1, 2018 6:00 AM", "end": "November 1, 2018 9:30 AM"}, {"title": "Birthday Party", "start": "November 10, 2018 12:30 PM", "end": "November 10, 2018 8:30 PM"}, {"title": "Football Tailgate with John", "start": "November 3, 2018 6:00 PM", "end": "November 3, 2018 10:00 PM"}]
"""
struct Event : Decodable {
let title : String
let start, end : Date
}
let formatter = DateFormatter()
formatter.locale = Locale(identifier: "en_US_POSIX")
formatter.dateFormat = "MMMM dd, yyyy h:mm a"
do {
let decoder = JSONDecoder()
decoder.dateDecodingStrategy = .formatted(formatter)
let result = try decoder.decode([Event].self, from: Data(jsonString.utf8))
print(result)
} catch {
print(error)
}
uj5u.com熱心網友回復：
-> 首先你需要接受正確的 JSON 資料
let json = """
{
"data" : [{"title": "Evening Picnic", "start": "November 10, 2018 6:00 PM", "end": "November 10, 2018 7:00 PM"}, {"title": "Nap Break", "start": "November 8, 2018 12:30 PM", "end": "November 8, 2018 1:30 PM"}, {"title": "Football Game", "start": "November 3, 2018 6:00 PM", "end": "November 3, 2018 10:00 PM"}, {"title": "Evening Cookout with Friends", "start": "November 6, 2018 5:00 PM", "end": "November 6, 2018 10:00 PM"}, {"title": "Roller Derby", "start": "November 7, 2018 12:00 PM", "end": "November 7, 2018 2:30 PM"}, {"title": "Basketball Game", "start": "November 8, 2018 7:30 PM", "end": "November 8, 2018 10:30 PM"}, {"title": "Local Pub with Friends", "start": "November 1, 2018 7:30 PM", "end": "November 1, 2018 11:00 PM"}, {"title": "Dentist Appointment", "start": "November 10, 2018 1:45 PM", "end": "November 10, 2018 2:30 PM"}, {"title": "Free Donuts", "start": "November 9, 2018 3:00 PM", "end": "November 9, 2018 4:00 PM"}, {"title": "TV Show Marathon", "start": "November 9, 2018 4:30 PM", "end": "November 9, 2018 9:00 PM"}, {"title": "Lunch with Friends", "start": "November 8, 2018 11:30 AM", "end": "November 8, 2018 1:00 PM"}, {"title": "SF Coffee Festival","start": "November 6, 2018 6:00 PM","end": "November 6, 2018 9:00 PM"}, {"title": "Beer with Friends", "start": "November 9, 2018 8:00 PM", "end": "November 9, 2018 9:30 PM"}, {"title": "Yoga", "start": "November 1, 2018 6:00 PM", "end": "November 1, 2018 7:30 PM"}, {"title": "Rock Concert", "start": "November 7, 2018 6:30 PM", "end": "November 7, 2018 11:00 PM"}, {"title": "Lunch Meeting", "start": "November 9, 2018 12:30 PM", "end": "November 9, 2018 2:30 PM"}, {"title": "Bicycling with Friends", "start": "November 1, 2018 6:00 AM", "end": "November 1, 2018 9:30 AM"}, {"title": "Birthday Party", "start": "November 10, 2018 12:30 PM", "end": "November 10, 2018 8:30 PM"}, {"title": "Football Tailgate with John", "start": "November 3, 2018 6:00 PM", "end": "November 3, 2018 10:00 PM"}]
}
"""
-> 那么你需要創建一個可編碼的類或結構
struct Main: Codable {
var data: [MYStruct]?
}
// MARK: - Datum
struct MYStruct: Codable {
var title, start, end: String?
}
-> 如果密鑰“開始”：“2018 年 11 月 3 日下午 6:00”這里的“開始”延遲，您可以像這樣使用 codingKey
struct MYStruct: Codable {
var title, start, end: String?
enum CodingKeys: String, CodingKey {
case title = "title" // key name as string
case startDate = "start"
case endDate = "end"
}
-> 然后創建一個JSON解碼器來解碼jsonData
override func viewDidLoad() {
super.viewDidLoad()
let jsonData = Data(json.utf8)
let decoder = JSONDecoder()
let loadedData = try? decoder.decode(Main.self, from: jsonData) // 1st parameter object name 2nd parameter JsonData
print(loadedData?.data?[0].title)
}
-> 請記住，您的 json 始終是正確的策略，并以 {} 結尾
-> 總是應該在密鑰對值中
->輸出
Optional("Evening Picnic")
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