[英]Swift Error: keyNotFound No value associated with key CodingKeys
[英]Swift4, JSON, keyNotFound, No value associated with key
我需要做 Sunset Sunrise App,这是我的代码。 但我有这个错误:
错误序列化 json: keyNotFound(Sunrise_Sunset.SunPosition.Results.(CodingKeys in _B4291256871B16D8D013EC8806040532).sunrise, Swift.DecodingError.Context(codingPath: [], debugDescription: "No value associated with key sunrise\\").\\"底层错误:无))
我不明白如何解决它。 也许有人有这个问题。 如有任何帮助,我将不胜感激)这是我拥有的 API: https : //sunrise-sunset.org/api
struct SunPosition: Codable {
struct Results: Codable {
let sunrise: String
let sunset: String
let solarNoon: String
let dayLenght: String
let civilTwilightBegin: String
let civilTwilightEnd: String
let nauticalTwilightBegin: String
let nauticalTwilightEnd: String
let astronomicalTwilightBegin: String
let astronomicalTwilightEnd: String
enum CodingKey:String, Swift.CodingKey {
case sunrise = "sunrise"
case sunset = "sunset"
case solarNoon = "solar_noon"
case dayLenght = "day_length"
case civilTwilightBegin = "civil_twilight_begin"
case civilTwilightEnd = "civil_twilight_end"
case nauticalTwilightBegin = "nautical_twilight_begin"
case nauticalTwilightEnd = "nautical_twilight_end"
case astronomicalTwilightBegin = "astronomical_twilight_begin"
case astronomicalTwilightEnd = "astronomical_twilight_end"
}
}
}
extension SunPosition.Results {
init(from decoder: Decoder) throws {
let values = try decoder.container(keyedBy: CodingKeys.self)
sunrise = try values.decode(String.self, forKey: .sunrise)
sunset = try values.decode(String.self, forKey: .sunset)
solarNoon = try values.decode(String.self, forKey: .solarNoon)
dayLenght = try values.decode(String.self, forKey: .dayLenght)
civilTwilightBegin = try values.decode(String.self, forKey: .civilTwilightBegin)
civilTwilightEnd = try values.decode(String.self, forKey: .civilTwilightEnd)
nauticalTwilightBegin = try values.decode(String.self, forKey: .nauticalTwilightBegin)
nauticalTwilightEnd = try values.decode(String.self, forKey: .nauticalTwilightEnd)
astronomicalTwilightBegin = try values.decode(String.self, forKey: .astronomicalTwilightBegin)
astronomicalTwilightEnd = try values.decode(String.self, forKey: .astronomicalTwilightEnd)
}
}
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let jsonUrlString = "https://api.sunrise-sunset.org/json?lat=36.7201600&lng=-4.4203400"
guard let url = URL(string: jsonUrlString) else { return }
URLSession.shared.dataTask(with: url) { (data, response, error) in
guard let data = data else { return }
do {
let sunPosition = try JSONDecoder().decode(SunPosition.Results.self, from: data)
print(sunPosition)
}catch let jsonErr {
print("Error serializing json:", jsonErr)
}
}.resume()
}
}
四个问题:
let results : Results
在SunPosition
结构中的let results : Results
。private enum CodingKeys: String, CodingKey
: private enum CodingKeys: String, CodingKey
而不是enum CodingKey :String, Swift.CodingKey
,注意单数/复数区别,推荐使用private
属性但不会导致问题。JSONDecoder().decode(SunPosition.self, from: data)
而不是JSONDecoder().decode(SunPosition.Results.self, from: data)
。results
您必须print(sunPosition.results)
。三注意事项:
在 URL 中添加&formatted=0
并将解码器的dateDecodingStrategy
设置为.iso8601
以获取Date
对象。 将所有与日期相关的属性的类型从String
更改为Date
,将dayLenght
的类型从String
更改为TimeInterval
。 改变dateDecodingStrategy
写
let decoder = JSONDecoder() decoder.dateDecodingStrategy = .iso8601 let sunPosition = try decoder.decode(SunPosition.self ...
我也建议处理status
。 将此添加到SunPosition
结构中
let status : String var success : Bool { return status == "OK" }
为了排除它,如果由于某种原因您的端点返回错误消息或零数据,您将收到此错误。
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