Question

我有一个类似

的结构

struct Channel {
    var id : Int = 0
    var name = ""
}

我正在从URL获取json

{"channel_list":[{"channel_id":0,"channel_name":"test1"},{"channel_id":0,"channel_name":"test2"}]}

但是我无法获取数据

func parseJson(anyObj:AnyObject) -> Array<Channel>{
    var list:Array<Channel> = []
    if  anyObj is Array<AnyObject> {
        var b:Channel = Channel()
        for json in anyObj as! Array<AnyObject>{
            b.id  =  (json["channel_id"]  as AnyObject? as? Int) ?? 0
            b.name = (json["channel_name"] as AnyObject? as? String) ?? ""
            list.append(b)
        }
    } 
    return list
}

//read code
let anyObj: AnyObject? = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions(0),error: nil) as AnyObject?
        println(anyObj)
        if let myobj=anyObj["channel_list"] as AnyObject {
            self.Channellist=self.parseJson(anyObj!)
        }

这有什么不对吗？

Answer 1

首先，不应使用AnyObject，而应将JSON响应转换为字典：[NSObject:AnyObject]然后将anyObj["channel_list"]的结果安全地转换为字典数组[[NSObject:AnyObject]] ，因为这是你的JSON响应格式。

然后您需要在parseJSON函数中使用此类型。我们也正在进行简化，因为不再需要进行奇怪的铸造了。

此外，您将错误的参数传递给您的函数（您使用的是anyObj而不是myObj）。

struct Channel {
    var id : Int = 0
    var name = ""
}

func parseJson(anyObj: [[NSObject:AnyObject]]) -> Array<Channel>{
    var list: Array<Channel> = []
    var b: Channel = Channel()
    for json in anyObj {
        b.id  =  (json["channel_id"] as? Int) ?? 0
        b.name = (json["channel_name"] as? String) ?? ""
        list.append(b)
    }
    return list
}

if let anyObj = NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions(0),error: nil) as? [NSObject:AnyObject] {
    if let myobj = anyObj["channel_list"] as? [[NSObject:AnyObject]] {
        self.Channellist=self.parseJson(myobj)
    }
}

还有改进的余地：例如，您可以为Struct创建初始化程序，并为响应类型创建一个类型，使用map创建列表等。

Answer 2

以下是我如何使用Swift 2：

struct Channel {
    var id : Int
    var name: String
    init?(JSON: [NSObject: AnyObject]?) {
          guard let channelID = json["channel_id"] as? Int, let channelName = json["channel_name"] as? String
          else { name = ""; id = 0; return nil }
          name = channelName
          id = channelID
    }
}
func parseJSON(array: [[NSObject:AnyObject]]) -> [Channel?] {
    return array.map { Channel(JSON: $0) }
    // If you don't want to return optionals to channel you can do this instead:
   // return array.map { Channel(JSON: $0) }.filter { $0 != nil }.map { $0! }
}
// And in the caller
do {
     guard let dict = try NSJSONSerialization.JSONObjectWithData(data!, options: []) as? [NSObject : AnyObject] 
     else { throw NSError(domain ... // Setup error saying JSON wasn't parsed. }
     guard let arrayContents = dict["channel_list"] as? [[NSObject:AnyObject]]
     else  { throw NSError(domain ... // Setup error saying array wasn't found. }
     let channels = parseJSON(arrayContents)
}
catch {
    print(error)
}

Swift将json解析为struct

2 个答案: