iOS 9，Swift 2.0：从JSON文件检索字典

Question

我试图访问JSON文件中的字典。 这是我第一次尝试读取JSON文件。 我正在寻找一种返回getImageId结果的方法，但是我的变量imageID不会更改为self.getImageId（keyWord，jsonDictionary：jsonDictionary！）返回的值！ 并保持为零。

func getEmotes(keyWord: String)-> NSNumber{
    //Returns NSURL?.  nil if the url is not valid
    let url = NSURL(string: urlString)
    let request = NSURLRequest(URL: url!)
    var imageID: NSNumber? = nil
    //Response: HHTP response, NSData the data contained in the file, NSError no internet, etc.
    NSURLConnection.sendAsynchronousRequest(request, queue: NSOperationQueue.mainQueue()) { (response: NSURLResponse?, data: NSData?, error: NSError?) in
        if error == nil{
            //To get URL response.
            let httpResponse = response as! NSHTTPURLResponse

            if httpResponse.statusCode == 200 {
                var jsonDictionary: NSDictionary? = nil

                do {
                    jsonDictionary = try NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions.MutableContainers) as? NSDictionary
                }catch{ }

                if jsonDictionary != nil{
                    //The retrieval Dictionary inside Json was sucesful.
                    //NEED: Return the value from this:
                    imageID = self.getImageId(keyWord, jsonDictionary: jsonDictionary!)!
                }
            }else{
                print(httpResponse.statusCode)
            }
        }

    }
    print(imageID)
    return imageID ?? 0
}

非常感谢。

Answer 1

您可以使用return块。 我没有在返回块中添加任何错误处理，您需要添加它。

getEmotes("keyword") { (imageID) in
    print(imageID)
}

func getEmotes(keyWord: String, returnBlock: (imageID: NSNumber?) -> Void)-> Void{
//Returns NSURL?.  nil if the url is not valid
let url = NSURL(string: urlString)
let request = NSURLRequest(URL: url!)
var imageID: NSNumber? = nil
//Response: HHTP response, NSData the data contained in the file, NSError no internet, etc.
NSURLConnection.sendAsynchronousRequest(request, queue: NSOperationQueue.mainQueue()) { (response: NSURLResponse?, data: NSData?, error: NSError?) in
    if error == nil{
        //To get URL response.
        let httpResponse = response as! NSHTTPURLResponse

        if httpResponse.statusCode == 200 {
            var jsonDictionary: NSDictionary? = nil

            do {
                jsonDictionary = try NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions.MutableContainers) as? NSDictionary
            }catch{ }

            if jsonDictionary != nil{
                //The retrieval Dictionary inside Json was sucesful.
                //NEED: Return the value from this:
                imageID = self.getImageId(keyWord, jsonDictionary: jsonDictionary!)!
                returnBlock(imageID: imageID)
            }
        }else{
            print(httpResponse.statusCode)
        }
    }

}

}