Question

我尝试过以下示例来解析JSON文件（例如，此处发布的另一个问题的答案：https://stackoverflow.com/a/27206145/4040201）但无法使其工作。我现在在“let ... = item [”...“]上得到错误”不能下载'AnyObject'类型的值'作为？String“行。

func connectionDidFinishLoading(connection: NSURLConnection) {

    do {
        let jsonResult = try NSJSONSerialization.JSONObjectWithData(self.bytes!, options: NSJSONReadingOptions.MutableContainers) as! Dictionary<String, AnyObject>

        if let searchResults = jsonResult["Search"] as? [AnyObject] {
            for item in searchResults {
                let title = item["Title"] as? String //Error Here
                let type = item["Type"] as? String //Error Here
                let year = item["Year"] as? String //Error Here

                print("Title: \(title) Type: \(type) Year: \(year)")
            }
        }

    } catch let error as NSError {
        NSLog("JSON Error: \(error)")
    }
}

JSON示例：

{ "Search": [
    {
    "Title":"Example 1",
    "Year":"2001",
    "Type":"Type1"
    },
    {
    "Title":"Example 2",
    "Year":"2006",
    "Type":"Type1"
    },
    {
    "Title":"Example 3",
    "Year":"1955",
    "Type":"Type1"
    }
]}

Answer 1

试试这个

func connectionDidFinishLoading(connection: NSURLConnection) {

    do {
        let jsonResult = try NSJSONSerialization.JSONObjectWithData(self.bytes!, options: NSJSONReadingOptions.MutableContainers) as! Dictionary<String, AnyObject>

        if let searchResults = jsonResult["Search"] as? [[String: AnyObject]] {
            for item in searchResults {
                let title = item["Title"]
                let type = item["Type"]
                let year = item["Year"]

                print("Title: \(title) Type: \(type) Year: \(year)")
            }
        }

    } catch let error as NSError {
        NSLog("JSON Error: \(error)")
    }
}

Answer 2

你可以这样做

let title : String
if let titleVal = item["Title"] as? String
{
   title = titleVal
   print(title)
}

这将检查Title属性值是否为null。如果它不为null，它将读取该值并设置为titleVal变量。

如果您确定它永远不会有空值，则可以使用此代码

let title = item["Title"] as! String

Swift 2解析JSON - 无法下标“AnyObject”类型的值

2 个答案: