Question

我正在学习Swift，我遇到了从URL文件解析JSON文件的问题。

我试图调用posts字典并从中解析audio值。

let url = URL(string: "https://api.myjson.com/bins/91nzd")
URLSession.shared.dataTask(with:url!, completionHandler: {(data, response, error) in
    guard let data = data, error == nil else { return }

    do {
        let json = try JSONSerialization.jsonObject(with: data, options: .allowFragments) as! [String:Any]
        let posts = json["posts"] as? [String: Any] ?? [:]
        print(posts)
        let audios = posts["audio"] as? [String: Any] ?? [:]
        print(audios)
    } catch let error as NSError {
        print(error)
    }
}).resume()

这会返回:, :，我认为这是一个零表达式。它调用的JSON文件如下所示：

{
  "posts": [
    {
      "id": "1",
      "title": "title 1",
      "audio": "https://rss-example.com/episodes/871ae23d.mp3"
    },
    {
      "id": "2",
      "title": "title 2",
      "audio": "https://rss-example.com/episodes/352ae29d.mp3"
    } 
  ] 
}

从我看过的教程中，这对我来说是正确的，但是你看到了错误吗？还是我误解了？

Answer 1

错误是帖子Array类型，请尝试：

    let url = URL(string: "https://api.myjson.com/bins/91nzd")
    URLSession.shared.dataTask(with:url!, completionHandler: {(data, response, error) in
        guard let data = data, error == nil else { return }

        do {
            let json = try JSONSerialization.jsonObject(with: data, options: .allowFragments) as! [String:Any]
            if let posts = json["posts"] as? Array {
                for (index, element) in posts.enumerate() {
                    let audios = element["audio"] as? [String: Any] ?? [:]     
                     print(audios)
                }
            } 
        } catch let error as NSError {
            print(error)
        }
    }).resume()

从Swift 3中的URL中提取JSON值返回＆＃34;：＆＃34;表达

1 个答案: