ios - Swift 4 Decodable 解析数组中的 json 数据

Question

我在解析来自 Web 服务的数据时遇到问题，可解码协议(protocol)似乎无法解析此 json

这是我使用泛型解析数据。

public func requestGenericData<T: Decodable>(urlString: String, httpMethod: String?, token: String!, completion: @escaping(T) ->()) {
    let fullStringUrl = url + urlString
    guard let url = URL(string: fullStringUrl) else { return }
    guard let token = token else { return }
    var urlRequest = URLRequest(url: url)
    urlRequest.setValue("application/json", forHTTPHeaderField: "accept")
    urlRequest.setValue("Bearer \(token)", forHTTPHeaderField: "Authorization")
    urlRequest.httpMethod = httpMethod
    URLSession.shared.dataTask(with: urlRequest) { (data, response, error) in
        if self.isInternetAvailable() {
            guard let data = data else { return }
            if let httpResponse = response as? HTTPURLResponse {
                if httpResponse.statusCode >= 200 && httpResponse.statusCode < 300 {
                    do {
                        let obj = try JSONDecoder().decode(T.self, from: data)
                        completion(obj)
                    } catch {
                        print("Error: \(String(describing: error))\n StatusCode: \(httpResponse.statusCode)")
                    }
                }
            }
        } else {
            showAlert(title: "No Internet Connect", message: "Please open your network and try again.", alertStyle: .alert, buttonTitle: "OK", buttonStyle: .default)
            return
        }
    }.resume()
}

这是我的模型

struct JobWithCategory: Decodable {
   let jobTypeID: Int
   let jobCategoryID: Int
   let name: String
   let getJobs: [getJobs]
}
struct getJobs: Decodable {
   let name: String
   let description: String
}
struct JobCategories: Decodable {
   let jobCategories: [JobWithCategory]
}


apiHelper.requestGenericData(urlString: "url/on/something/else", httpMethod: "GET", token: token) { (jobCategories: [JobCategories]) in
        print(jobCategories)
    }

现在我在控制台上打印了这个问题:

Error: typeMismatch(Swift.Array, Swift.DecodingError.Context(codingPath: [], debugDescription: "Expected to decode Array but found a dictionary instead.", underlyingError: nil))

我的实现过程中遗漏了什么或出了什么问题吗？有人可以帮我解决这个问题吗？请详细说明为什么会发生这种情况，以便我可以很好地了解代码中发生的情况。

提前致谢:)

Answer 1

请阅读错误消息

Expected to decode Array but found a dictionary instead

预期一侧显示您正在做什么(错误)，发现一侧显示实际类型。

就可解码而言，字典是一个结构。所以是这样的

...{ (jobCategories: JobCategories) in