缺少json文件/struct错误_Json_Swift_Parsing

缺少json文件/struct错误

json swift parsing

缺少json文件/struct错误,json,swift,parsing,Json,Swift,Parsing,我已经试着让这个代码工作了6个小时。我得到错误：“无法转换数据，无法读取，因为它丢失了。”我不知道文件丢失时，我的模型（结构）中是否有错误。我是否需要为每个json字典编写一个结构？目前，我只将这些JSON字典制作成一个结构，这是我实际需要的。完整的JSON文件可以在上找到。我想能够打印日出、日落和太阳正午的时间，以及太阳正午的太阳高度。现在是凌晨1点，我很绝望。晚安 class ViewController: NSViewController { @IBOutlet weak

我已经试着让这个代码工作了6个小时。我得到错误：“无法转换数据，无法读取，因为它丢失了。”我不知道文件丢失时，我的模型（结构）中是否有错误。我是否需要为每个json字典编写一个结构？目前，我只将这些JSON字典制作成一个结构，这是我实际需要的。完整的JSON文件可以在上找到。我想能够打印日出、日落和太阳正午的时间，以及太阳正午的太阳高度。现在是凌晨1点，我很绝望。晚安

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
}

从json数据（第二项）来看，您至少需要：

struct MyTime : Codable {
 let solarnoon : Solarnoon?
 let sunset : Sunset?
 let sunrise : Sunrise?
}

你需要：

        var result: MyData?
        do {
            result = try JSONDecoder().decode(MyData.self, from: data)
        }
        catch {
            print("----> error failed to convert \(error)")
        }

从json数据（第二项）来看，您至少需要：

struct MyTime : Codable {
 let solarnoon : Solarnoon?
 let sunset : Sunset?
 let sunrise : Sunrise?
}

你需要：

        var result: MyData?
        do {
            result = try JSONDecoder().decode(MyData.self, from: data)
        }
        catch {
            print("----> error failed to convert \(error)")
        }

您没有真正的SwiftUI类，但这是一个不同的问题。我将致力于修复getData（）。我试着对其进行广泛的评论，但如果您有任何问题，请告诉我

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()
}

对于结构，您只需要将它们用于您试图解析的数据。如果你不需要，不要担心。我会将其作为一个单独的类，名为MetDecoder，或者其他对您有意义的类，并指示JSON的解码器。您还将注意到，我更改了一些变量的名称。您可以这样做，只要您使用CodingKeys枚举将JSON转换为结构，如

dailyData=“location”

等。这是难看的JSON，我不确定为什么Met决定所有内容都应该是字符串，但此解码器经过测试，可以工作：

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?
}

你应该看看美国国家气象局对我们做了什么来获取JSON。最后，在处理JSON时，我发现以下页面非常有用：这将帮助您解析出在浏览器中返回的大量文本

这将把JSON解析成像Swift这样的编程语言。我将警告您，解析可能会在Swift中产生一些非常难看的结构，但它为您提供了一个良好的开端。我使用了这两个网站来回答这个问题。

你没有真正的SwiftUI类，但这是一个不同的问题。我将致力于修复getData（）。我试着对其进行广泛的评论，但如果您有任何问题，请告诉我

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()
}

dailyData=“location”

等。这是难看的JSON，我不确定为什么Met决定所有内容都应该是字符串，但此解码器经过测试，可以工作：

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?
}

你应该看看美国国家气象局对我们做了什么来获取JSON。最后，在处理JSON时，我发现以下页面非常有用：这将帮助您解析出在浏览器中返回的大量文本

这将把JSON解析成像Swift这样的编程语言。我将警告您，解析可能会在Swift中产生一些非常难看的结构，但它为您提供了一个良好的开端。我使用了这两个站点来回答这个问题。

苹果的新框架Combine有助于简化异步获取请求所需的代码。我在上面@Yrb的响应中使用了MetDecoder（您可以接受他的答案），并修改了getData（）函数。只需确保在顶部导入联合收割机即可

import Combine

var sunriseTime: String?
var sunsetTime: String?
var solarNoonTime: String?
var solarNoonElevation: String?

func getData() {
    let url = URL(string: "https://api.met.no/weatherapi/sunrise/2.0/.json?lat=40.7127&lon=-74.0059&date=2020-12-22&offset=-05:00")!
    
    URLSession.shared.dataTaskPublisher(for: url)
        // fetch on background thread
        .subscribe(on: DispatchQueue.global(qos: .background))
        // recieve response on main thread
        .receive(on: DispatchQueue.main)
        // ensure there is data
        .tryMap { (data, response) in
            guard
                let httpResponse = response as? HTTPURLResponse,
                httpResponse.statusCode == 200 else {
                throw URLError(.badServerResponse)
            }
            return data
        }
        // decode JSON data to MetDecoder
        .decode(type: MetDecoder.self, decoder: JSONDecoder())
        // Handle results
        .sink { (result) in
            // will return success or failure
            print("completion: \(result)")
        } receiveValue: { (value) in
            // if success, will return MetDecoder
            // here you can update your view
            print("value: \(value)")
            if let solarData = value.dailyData?.solarData?.first {
                self.sunriseTime = solarData.sunrise?.time
                self.sunsetTime = solarData.sunset?.time
                self.solarNoonTime = solarData.solarnoon?.time
                self.solarNoonElevation = solarData.solarnoon?.elevation
            }
        }
        // After recieving response, the URLSession is no longer needed & we can cancel the publisher
        .cancel()
}

import Combine

var sunriseTime: String?
var sunsetTime: String?
var solarNoonTime: String?
var solarNoonElevation: String?

func getData() {
    let url = URL(string: "https://api.met.no/weatherapi/sunrise/2.0/.json?lat=40.7127&lon=-74.0059&date=2020-12-22&offset=-05:00")!
    
    URLSession.shared.dataTaskPublisher(for: url)
        // fetch on background thread
        .subscribe(on: DispatchQueue.global(qos: .background))
        // recieve response on main thread
        .receive(on: DispatchQueue.main)
        // ensure there is data
        .tryMap { (data, response) in
            guard
                let httpResponse = response as? HTTPURLResponse,
                httpResponse.statusCode == 200 else {
                throw URLError(.badServerResponse)
            }
            return data
        }
        // decode JSON data to MetDecoder
        .decode(type: MetDecoder.self, decoder: JSONDecoder())
        // Handle results
        .sink { (result) in
            // will return success or failure
            print("completion: \(result)")
        } receiveValue: { (value) in
            // if success, will return MetDecoder
            // here you can update your view
            print("value: \(value)")
            if let solarData = value.dailyData?.solarData?.first {
                self.sunriseTime = solarData.sunrise?.time
                self.sunsetTime = solarData.sunset?.time
                self.solarNoonTime = solarData.solarnoon?.time
                self.solarNoonElevation = solarData.solarnoon?.elevation
            }
        }
        // After recieving response, the URLSession is no longer needed & we can cancel the publisher
        .cancel()
}

能否将

打印（“未能转换\（错误.本地化说明）”）

更改为

打印（“未能转换\（错误）”）

，并告诉我们您得到了什么？能否将

打印（“未能转换\（错误.本地化说明）”）

更改为

打印（“未能转换\（错误）”

，告诉我们你得到了什么？这个答案很美！我还在为联合收割机绞尽脑汁……这个答案真是太美了！我还在用我的头缠绕联合收割机。。。