在 SwiftUI 中解码汇率 JSON [英] Decoding Exchange Rate JSON in SwiftUI

问题描述

我正在尝试解码 https://api.exchangeratesapi.io/latest，由提供汇率 API.我正在应用我在网上找到的几个教程，但是当我应用自己的详细信息时，出现错误.我的代码如下所示:

I am trying to decode https://api.exchangeratesapi.io/latest, provided by Exchange Rates API. I'm applying several tutorials I found online, but when I apply my own details, I get an error. My code looks as following:

struct Response: Codable {
    var results: [Result]
}

struct Result: Codable {
    let base: String
    let date: String
    let rates: [String:Double]
}

检索数据的函数:

func loadData() {
    guard let url = URL(string: "https://api.exchangeratesapi.io/latest") else {
        print("Invalid URL")
        return
    }
    let request = URLRequest(url: url)
    URLSession.shared.dataTask(with: request) { data, response, error in
        if let data = data {
            if let decodedResponse = try? JSONDecoder().decode(Response.self, from: data) {
                // we have good data – go back to the main thread
                DispatchQueue.main.async {
                    // update our UI
                    self.results = decodedResponse.results
                }
                // everything is good, so we can exit
                return
            }
        }
        // if we're still here it means there was a problem
        print("Fetch failed: (error?.localizedDescription ?? "Unknown error")")
    }.resume()
}

我的看法:

import SwiftUI

struct ExchangeRateTest: View {
    @State private var results = [Result]()

    var body: some View {
                List(results, id: .base) { item in
            VStack(alignment: .leading) {
                Text(item.base)
            }
        }.onAppear(perform: loadData)
    }
}

我得到的错误是:Fetch Failed: Unknown Error，提示应用程序无法读取在线数据.这是什么原因造成的?

The error I get is: Fetch Failed: Unknown Error, suggesting that the app is not able to read the online data. What can cause this?

这与我的网络连接无关；如果我应用另一个 JSON，这种方法可以正常工作.

It has nothing to do with my network connection; if I apply another JSON this approach works fine.

任何帮助将不胜感激.

推荐答案

你可以这样读:

struct RateResult: Codable {
    let rates: [String: Double]
    let base, date: String
}

struct ContentView: View {
    @State private var results = RateResult(rates: [:], base: "", date: "")

    func loadData() {
        guard let url = URL(string: "https://api.exchangeratesapi.io/latest") else {
            print("Invalid URL")
            return
        }
        let request = URLRequest(url: url)
        URLSession.shared.dataTask(with: request) { data, response, error in
            if let data = data {
                if let decodedResponse = try? JSONDecoder().decode(RateResult.self, from: data) {
                    // we have good data – go back to the main thread
                    DispatchQueue.main.async {
                        // update our UI
                        self.results = decodedResponse
                    }
                    // everything is good, so we can exit
                    return
                }
            }
            // if we're still here it means there was a problem
            print("Fetch failed: (error?.localizedDescription ?? "Unknown error")")
        }.resume()
    }

这篇关于在 SwiftUI 中解码汇率 JSON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IT屋！