ios - Json解析错误: use of undeclared type 'Foundation' in Swift iOS

Question

我正在使用 Swift 创建一个应用程序，我必须在其中显示使用以下 URL 的国家/地区列表:

https://restcountries.eu/rest/v2/all

在这里，我只需要获取 name 键并添加到我的 NSMutableArray 中。当我尝试使用 URLSession 解析它时，出现错误:

expression produced error: error: /var/folders/_3/27lhgzw9699c4_yg37r72_d80000gp/T/expr40-bcf47d..swift:1:65: error: use of undeclared type 'Foundation'
Swift._DebuggerSupport.stringForPrintObject(Swift.UnsafePointer<Foundation.Data>(bitPattern: 0x105c0c2f0)!.pointee)

下面是我的代码:

func fetchCountryList(countryURL:URL, completion:@escaping (NSDictionary) -> ()) {

            print(countryURL)

            let request = NSMutableURLRequest( url: countryURL as URL)

            let task = URLSession.shared.dataTask(with: request as URLRequest) {
                data, response, error in
                do{
                    if let data = data,
                        let jsonString =  try JSONSerialization.jsonObject(with: data, options: JSONSerialization.ReadingOptions.mutableContainers) as? NSDictionary
                        , error == nil {
                        completion(jsonString)
                    } else {
                        print("error=\(error!.localizedDescription)")
                        let errorDict = ["error_status":true,"message":error!.localizedDescription] as [String : Any]
                        completion(errorDict as NSDictionary)

                    }
                }
                catch{
                    print("error=\(error.localizedDescription)")
                    let errorDict = ["error_status":true,"message":error.localizedDescription] as [String : Any]
                    completion(errorDict as NSDictionary)

                }

            }
            task.resume()
    }

任何人都可以在这里告诉我我的错误。提前致谢!

Answer 1

替换

try JSONSerialization.jsonObject(with: data, options: JSONSerialization.ReadingOptions.mutableContainers) as? NSDictionary

与

try JSONSerialization.jsonObject(with: data, options: JSONSerialization.ReadingOptions.mutableContainers) as? [[String: Any]]

因为它是一个对象数组，我们还需要将 json 转换为 array

要获取国家名称数组，我们可以通过以下方式实现:

guard let countries = try JSONSerialization.jsonObject(with: data, options: JSONSerialization.ReadingOptions.mutableContainers) as? [[String: Any]] else {
    return
}
let countryNames = countries.map { $0["name"] as! String }