Question

我目前正在尝试完成有关读取JSON文件的在线教程，该教程文件让我们输入了以下代码

override func viewDidLoad() {
    super.viewDidLoad()

    if let url = NSURL(string: "https://api.forecast.io/forecast/d3250bf407f0579c8355cd39cdd4f9e1/37.7833,122.4167") {
        if let data = NSData(contentsOfURL: url){
            do {
                let parsed = try NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.AllowFragments)

                let newDict = parsed as? NSDictionary
                print(newDict!["currently"]!["summary"])
            }
            catch let error as NSError {
                print("A JSON parsithng error occurred, here are the details:\n \(error)")
            }
        }
    }
}

}

当我迅速输入代码时，它会自动将大多数代码纠正为：

override func viewDidLoad() {
    super.viewDidLoad()

    if let url = URL(string: "https://api.forecast.io/forecast/d3250bf407f0579c8355cd39cdd4f9e1/42.2111,-88.3162") {
        if let data = NSData(contentsOf: url){
            do {
                let parsed = try JSONSerialization.jsonObject(with: data as Data, options: JSONSerialization.ReadingOptions.allowFragments)

                let newDict = parsed as? NSDictionary
                print(newDict!["currently"]!["summary"])
            }
            catch let error as NSError {
                print("A JSON parsithng error occurred, here are the details:\n \(error)")
            }
        }
    }
}

我现在在print(newDict!["currently"]!["summary"])行遇到错误，因为类型'Any'没有下标成员，而且我不确定如何解决。卸下！产生一个错误，指出必须有一个！还是？但是放任一个都会使我回到这个“任何”错误。您能提供的任何帮助将不胜感激

Answer 1

您可以尝试

if let newDict = parsed as? [String:Any] {
   if let curr = newDict["currently"] as? [String:Any] {
      print(curr["summary"])
   }
}

因为此newDict!["currently"]!将返回Any，在将其强制转换为["summary"]之前，您无法使用[String:Any]下标

Swift Dark Sky API天气应用程序“ Any”类型没有下标成员

1 个答案: