<分区>
<分区>
我在使用这段本质上下载 JSON 数据并对其进行解析以返回 returnInfo 的代码时遇到了问题。当我打印信息时，它是完整的，但是当它被返回时，结构默认值被返回。不确定我做错了什么任何帮助将不胜感激!
如果您需要任何其他信息，请告诉我，我很乐意提供。
import Foundation
struct stockData {
var name: String = ""
var askPrice: String = ""
var percentageChange: String = ""
}
class stockinfo {
init () {
}
func getInfo (stock: String) -> stockData{
let stockSymbol = stock // Sets stock symbol
var returnInfo = stockData()
// Configuration for request and starts the connection
let requestURL: NSURL = NSURL(string: "https://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20yahoo.finance.quotes%20where%20symbol%20in%20(%22" + stockSymbol + "%22)&env=store://datatables.org/alltableswithkeys&format=json")!
let urlRequest: NSMutableURLRequest = NSMutableURLRequest(URL: requestURL)
let session = NSURLSession.sharedSession()
let task = session.dataTaskWithRequest(urlRequest) {
(data, response, error) -> Void in
let httpResponse = response as! NSHTTPURLResponse
let statusCode = httpResponse.statusCode
if (statusCode == 200) {
print("JSON File Downloaded Successfully")
do{
let json = try NSJSONSerialization.JSONObjectWithData(data!, options:.AllowFragments)
// Parses out the JSON Query into data to be assigned to a variable and returned
let query: NSDictionary = json["query"] as! NSDictionary
let results: NSDictionary = query["results"] as! NSDictionary
let quote: NSDictionary = results["quote"] as! NSDictionary
let companyName: String = quote["Name"] as! String
let askPrice: String = quote["Ask"] as! String
let percentageChange: String = quote["ChangeinPercent"] as! String
// Places JSON data into return struct
print(companyName)
print(askPrice)
print(percentageChange)
returnInfo.name = companyName
returnInfo.askPrice = askPrice
returnInfo.percentageChange = percentageChange
} catch {
print("Error with Json: \(error)")
}
}
}
task.resume()
return returnInfo
}
}
最佳答案
您需要一个完成处理程序来等待 async 调用 dataTaskWithRequest 完成。像这样修改您的代码:
func getInfo (stock: String, completion: (cName: String, price: String, percentChange: String) -> ()) -> stockData{
//your code
let companyName: String = quote["Name"] as! String
let askPrice: String = quote["Ask"] as! String
let percentageChange: String = quote["ChangeinPercent"] as! String
// Places JSON data into return struct
print(companyName)
print(askPrice)
print(percentageChange)
completion(cName: companyName, price: askPrice, percentChange: percentageChange)
}
//your code
然后每当你想调用它时，基本上是在按下按钮之后，或者如果你喜欢在 viewDidLoad 中调用它:
getInfo("your string") {(name, price, change) in
///use the three values how you want.
}
关于ios - 使用 Swift 返回具有自定义数据类型的 JSON 数据时遇到问题，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/38130704/
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