此 API 调用解析 JSON 数据时遇到问题吗？

Question

这是 SWIFTUI 代码的代码，它使用 JSON 数据解析并显示 API。

//
//  trivia.swift
//  hw4
//
//  Created by somebody else on 4/15/24.
//
//
    import SwiftUI
    struct Trivia: Identifiable, Decodable {
    let id = UUID()
        var type: String
    var difficulty: String
    var category: String
        var question: String
        var correct: String
    }
enum CodingKeys: String, CodingKey {
    case type, difficulty, category, question, correct, incorrect
}
    struct TriviaView: View {
        @State private var trivia = [Trivia]()
        var body: some View {
            NavigationView {
            List(trivia) { t in
                VStack (alignment: .leading) {
                    Text(t.question)
                        .font(.headline)
                        .foregroundColor(.cyan)
                    Text(t.type)
                        .font(.body)
                        .foregroundColor(.black)
                    Text(t.difficulty)
                        .font(.body)
                        .foregroundColor(.black)
                    Text(t.correct)
                        .font(.headline)
                        .foregroundColor(.green)
                   
                                }
            }
            .navigationTitle("Trivia Questions List")
            .task {
                await fetchTriviaData()
            }
        }
    }
    
    func fetchTriviaData() async {
        // create the URL
        guard let url = URL(string: "https://opentdb.com/api.php?amount=20&type=multiple)") else {
            
            print("THIS URL DOES NOT WORK!")
            return
        }
        // fetch the data
        do {
            let (results, _) = try await URLSession.shared.data(from: url)
            // decode that data
           if let decodedResponse = try? JSONDecoder().decode(TriviaResponse.self, from: results)
            {
               trivia = decodedResponse.results
           }
            
            } catch {
print("This data is not valid: \(error)")
// ecode the data
}
}
}
struct TriviaResponse: Decodable {
    let results: [Trivia]
}
struct TriviaView_Previews: PreviewProvider {
static var previews: some View {
TriviaView()
}
}

这段代码的目标是能够使用URL查看json数据。当我单击假期列表的导航标题时，没有显示任何数据（在内容视图中）。我尝试过其他 API 链接，例如 JSON 的 API 占位符，并且它们有效。我无法弄清楚问题或差异。我也尝试过人工智能。我不知道我做错了什么，难道我必须使用API的所有数据变量吗？

我尝试使用这个问题作为我的新问题的模板这个API调用解析JSON数据有什么问题？，它不起作用，我想知道问题是什么。

Answer 1

伙计，尝试这个示例代码来修复您遇到的一些错误，但没有从上一篇文章中学到。

struct TriviaResponse: Decodable {
    let results: [Trivia]
}

struct Trivia: Identifiable, Decodable {
    let id = UUID()
    var type: String
    var difficulty: String
    var category: String
    var question: String
    var correct: String?
    
    // --- here, inside
    enum CodingKeys: String, CodingKey {
        case type, difficulty, category, question, correct
    }
}

// for testing
struct ContentView: View {
    var body: some View {
        TriviaView()
    }
}

struct TriviaView: View {
    @State private var trivia = [Trivia]()
    
    var body: some View {
        NavigationStack {  // <--- here
            List(trivia) { t in
                VStack (alignment: .leading) {
                    Text(t.question)
                        .font(.headline)
                        .foregroundColor(.cyan)
                    Text(t.type)
                        .font(.body)
                        .foregroundColor(.black)
                    Text(t.difficulty)
                        .font(.body)
                        .foregroundColor(.black)
                    Text(t.correct ?? "")  // <--- here
                        .font(.headline)
                        .foregroundColor(.green)
                }
            }
            .navigationTitle("Trivia Questions List")
            .task {
                await fetchTriviaData()
            }
        }
    }
    
    func fetchTriviaData() async {
        // --- here had a extra `)`
        guard let url = URL(string: "https://opentdb.com/api.php?amount=20&type=multiple")  else {
            print("THIS URL DOES NOT WORK!")
            return
        }
        do {
            let (data, _) = try await URLSession.shared.data(from: url)
            // <--- here
            let decodedResponse = try JSONDecoder().decode(TriviaResponse.self, from: data)
            trivia = decodedResponse.results
        } catch {
            print("This data is not valid: \(error)")
        }
    }
}

Answer 2

1- 将

try?

更改为

try

    do {
          let (results, _) = try await URLSession.shared.data(from: url)
          // decode that data
          let decodedResponse = try JSONDecoder().decode(TriviaResponse.self, from: results)
           trivia = decodedResponse.results
   } catch {
     print("This data is not valid: \(error)")
   }

2-您会收到此错误

此数据无效： keyNotFound(CodingKeys(stringValue: " Correct", intValue: nil), Swift.DecodingError.Context(codingPath: [CodingKeys(stringValue: "results", intValue: nil), _JSONKey(stringValue: "Index 0”，intValue：0）]，debugDescription：“没有与键 CodingKeys 关联的值（stringValue：“正确”，intValue：nil）（“正确”）。”，underlyingError：nil））

这意味着没有正确的代号，但它应该是可选的正确答案