问题描述
我一直在尝试使此代码工作6个小时.我收到错误消息:由于缺少数据，无法读取数据."我不知道文件丢失了，但是我的模型(结构)出了点问题.我需要为json字典编写结构吗?目前，我只将那些JSON字典制作成了我真正需要的结构.完整的JSON文件可在 https://api.met.no/weatherapi/sunrise/2.0/.json?lat=40.7127&lon=-74.0059&date=2020-12 -22& offset = -05:00 .我希望能够打印日出，日落和太阳正午的时间，以及太阳正午的仰角.目前是凌晨1点，我很绝望.晚安！
I have been trying to get this code to work for like 6 hours. I get the error: "failed to convert The data couldn’t be read because it is missing." I don't know while the File is missing is there something wrong in my models(structs). Do I need to write a struct for very json dictionary? Currently I have only made those JSON dictionaries to a struct, which I actually need. The full JSON file can be found at https://api.met.no/weatherapi/sunrise/2.0/.json?lat=40.7127&lon=-74.0059&date=2020-12-22&offset=-05:00 . I want to be able to print the time of the sunrise, sunset and solar noon as well as the elevation of the sun at solar noon. It's currently 1 am and I am desperate. Good Night!
class ViewController: NSViewController {
@IBOutlet weak var sunriseField: NSTextField!
@IBOutlet weak var sunsetField: NSTextField!
@IBOutlet weak var daylengthField: NSTextField!
override func viewDidLoad() {
super.viewDidLoad()
let url = "https://api.met.no/weatherapi/sunrise/2.0/.json?lat=40.7127&lon=-74.0059&date=2020-12-22&offset=-05:00"
getData(from: url)
// Do any additional setup after loading the view.
}
private func getData(from url: String) {
let task = URLSession.shared.dataTask(with: URL(string: url)!, completionHandler: {data, response, error in
guard let data = data, error == nil else {
print("something went wrong")
return
}
var result: MyTime?
do {
result = try JSONDecoder().decode(MyTime.self, from: data)
}
catch {
print("failed to convert \(error.localizedDescription)")
}
guard let json = result else {
return
}
let sunrise1 = json.sunrise.time
DispatchQueue.main.async { [weak self] in
self?.sunriseField.stringValue = sunrise1
}
print(json)
})
task.resume()
}
override var representedObject: Any? {
didSet {
// Update the view, if already loaded.
}
}
}
struct MyData : Codable {
let location : Location
let meta : Meta
}
struct MyTime : Codable {
let solarnoon : Solarnoon
let sunset : Sunset
let sunrise : Sunrise
}
struct Location : Codable {
let height : String
let time : [MyTime]
let longitude : String
let latitude : String
}
struct Meta : Codable {
let licenseurl : String
}
struct Solarnoon : Codable {
let desc : String
let time : String
let elevation : String
}
struct Sunrise : Codable {
let desc : String
let time : String
}
struct Sunset : Codable {
let time : String
let desc : String
}
推荐答案
您实际上没有SwiftUI类，但这是一个不同的问题.我将致力于修复getData().我已尝试对其进行广泛评论，但是如果您有任何疑问，请告诉我.
You don't really have a SwiftUI class, but that is a different question. I am going to work on fixing getData(). I have tried to comment it extensively, but let me know if you have any questions.
private func getData(from url: String) {
// Personally I like converting the string to a URL to unwrap it and make sure it is valid:
guard let url = URL(string: urlString) else {
print("Bad URL: \(urlString)")
return
}
let config = URLSessionConfiguration.default
// This will hold the request until you have internet
config.waitsForConnectivity = true
URLSession.shared.dataTask(with: url) { data, response, error in
// A check for a bad response
guard let httpResponse = response as? HTTPURLResponse,
httpResponse.statusCode == 200 else {
print("Bad Server Response")
return
}
if let data = data {
// You can print(data) here that will shown you the number of bytes returned for debugging.
//This work needs to be done on the main thread:
DispatchQueue.main.async {
let decoder = JSONDecoder()
if let json = try? decoder.decode(MetDecoder.self, from: data){
print(json)
//At this point, you have your data in a struct
self.sunriseTime = json.dailyData?.solarData?.first?.sunrise?.time
}
}
}
}
.resume()
}
关于结构，您只需要它们用于尝试解析的数据.如果您不需要它，不必担心.我将其作为一个单独的类命名为MetDecoder或对您有意义并指示您的JSON的解码器的类.您还将注意到，我更改了一些变量的名称.只要您使用CodingKeys枚举将JSON转换为结构(例如dailyData = "location"等)，就可以这样做.这是丑陋的JSON，而且我不确定为什么Met决定所有内容都应该是字符串，但是此解码器已经过测试，并且可以正常工作:
With regard to your structs, you only need them for the data you are trying to parse. If you don't need it, don't worry about it. I would make this a separate class named MetDecoder or something that makes sense to you and indicates the decoder for your JSON. You will also note that I changed the names of some of the variables. You can do that so long as you use a CodingKeys enum to translate your JSON to your struct as in the case of dailyData = "location", etc. This is ugly JSON, and I am not sure why the Met decided everything should be a string, but this decoder is tested and it works:
import Foundation
// MARK: - MetDecoder
struct MetDecoder: Codable {
let dailyData: DailyData?
enum CodingKeys: String, CodingKey {
case dailyData = "location"
}
}
// MARK: - Location
struct DailyData: Codable {
let solarData: [SolarData]?
enum CodingKeys: String, CodingKey {
case solarData = "time"
}
}
// MARK: - Time
struct SolarData: Codable {
let sunrise, sunset: RiseSet?
let solarnoon: Position?
let date: String?
enum CodingKeys: String, CodingKey {
case sunrise, sunset, solarnoon, date
}
}
// MARK: - HighMoon
struct Position: Codable {
let time: String?
let desc, elevation, azimuth: String?
}
// MARK: - Moonrise
struct RiseSet: Codable {
let time: String?
let desc: String?
}
您应该查看美国国家气象局对我们的处理方式，以获取JSON.最后，在使用JSON时，我发现以下页面非常有帮助: JSON格式化程序&验证程序，它将帮助您解析在浏览器中返回的文本墙，以及 quicktype ，它将JSON解析为Swift之类的编程语言.我会警告您，解析可以在Swift中提供一些非常丑陋的结构，但它为您提供了一个不错的开始.我将两个站点都用于此答案.
You should see what the National Weather Service does to us in the US to get the JSON. Lastly, when working on JSON I find the following pages VERY helpful:JSON Formatter & Validator which will help you parse out the wall of text that gets returned in a browser, andquicktype which will parse JSON into a programming language like Swift. I will warn you that the parsing can give some very ugly structs in Swift, but it gives you a nice start. I used both sites for this answer.
这篇关于json文件丢失/结构错误的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！