json - 在函数内调用函数并返回字符串

Question

我有一个名为 getEarthquake() 的函数，它使用 SwiftyJSON 解析 JSON 并返回所有组织的信息(例如 title、magnitude和 time)到名为 info 的 NSMutableArray 中。

var info = NSMutableArray()

    func getEarthquake(completion: (results : NSMutableArray) ->Void) {
        DataManager.getEarthquakeDataFromFileWithSuccess {
            (data) -> Void in
            let json = JSON(data: data)
            if var JsonArray =  json.array {
                JsonArray.removeAtIndex(0)
                for appDict in JsonArray {
                    var mag: String? = appDict["mag"].stringValue
                    var title: String? = appDict["title"].stringValue
                    var time: String? = appDict["time"].stringValue
                    var information = AppModel(title: title, magnitude: mag, time1: time)
                    info.addObject(information)
               //     info.removeRange(3...48)

                    completion(results: info)
                }
            }

        }
    }

我创建了另一个名为 getEarthquake2() 的函数，它调用 getEarthquake() 并检索info。在 getEarthquake2() 中，我希望它仅返回 title1，它是一个 String。然而，我的尝试仅导致 title1 在返回时为 nil。

func getEarthquake2()->String? {
    var title1: String?
    getEarthquake{ (info) in

        var title = info[0].title
        title1 = title

    }

   return title1

}

有人可以在使 getEarthquake2() 成功返回不返回 nil 的 title1 时指导我正确的方向吗？ (我确信这不是 Info 为零的问题，因为它是在 getEarthquake() 末尾填充的。)

我的 AppModel.swift 文件，我可以在其中轻松组织我的代码:

import Foundation
class AppModel: NSObject, Printable {
    let title: String
    let magnitude: String
    let time1: String

    override var description: String {
        return "TITLE: \(title), TIME: \(time1), MAG: \(magnitude)"
    }
    init(title: String?, magnitude: String?, time1: String?) {
        self.title = title ?? ""
        self.time1 = time1 ?? ""
        self.magnitude = magnitude ?? ""
    }

}

我在其中调用 Web 服务的 DataManager.swift 文件:

import Foundation
let earthquakeURL = "http://www.kuakes.com/json/"
class DataManager {
    class func getEarthquakeDataFromFileWithSuccess(success: ((websiteData: NSData) -> Void)) {
        //1
        loadDataFromURL(NSURL(string: earthquakeURL)!, completion:{(data, error) -> Void in
            //2
            if let urlData = data {
                //3
                success(websiteData: urlData)
            }
            else {
                println("nothing")
            }
        })
    }
    class func loadDataFromURL(url: NSURL, completion:(data: NSData?, error: NSError?) -> Void) {
        var session = NSURLSession.sharedSession()

        // Use NSURLSession to get data from an NSURL
        let loadDataTask = session.dataTaskWithURL(url, completionHandler: { (data: NSData!, response: NSURLResponse!, error: NSError!) -> Void in
            if let responseError = error {
                completion(data: nil, error: responseError)
            } else if let httpResponse = response as? NSHTTPURLResponse {
                if httpResponse.statusCode != 200 {
                    var statusError = NSError(domain:"com.kuakes", code:httpResponse.statusCode, userInfo:[NSLocalizedDescriptionKey : "HTTP status code has unexpected value."])
                    completion(data: nil, error: statusError)
                } else {
                    completion(data: data, error: nil)
                }
            }
        })

        loadDataTask.resume()
    }







}

Answer 1

在 getEarthquake2 中，您忘记将对象转换为 AppModel:

func getEarthquake2() -> String? {
    var title1: String?

    getEarthquake { info in
        let title = (info[0] as! AppModel).title
        title1 = title
    }

    return title1
}