Alamofire网络提取的完成处理程序 [英] Completion handler for Alamofire network fetch

问题描述

我正在尝试创建一个函数，该函数将返回通过解析JSON创建的自定义对象列表。我正在使用AlamoFire下载内容。我写了这个函数，成功后创建了一个要返回的位置数组。但是，回报总是为零。我的代码如下：

I am attempting to create a function which will return a list of custom objects, created from parsing JSON. I am using AlamoFire to download the content. I have written this function which, on success, creates an array of locations to be returned. However, the returns are always nil. My code is below:

func fetchLocations() -> [Location]? {
    var locations : [Location]?
    Alamofire.request(.GET, myURL)
        .responseJSON { response in
            switch response.result {
             case .Success(let data):
                locations = createMapLocations(data)
            case .Failure(let error):
                print("Request failed with error: \(error)")
            }
        }
    return locations
}

我非常肯定问题是功能在网络请求之前返回做完了。我是Swift的新手，不确定如何处理这个问题。任何帮助将不胜感激！

I am pretty positive the issue is that the functioning is returning before the network request is complete. I am new to Swift, and unsure how to handle this. Any help would be appreciated!

推荐答案

您可以阅读有关闭包/完成处理程序的更多信息 https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Closures .html 或谷歌。

You can read more about closures/ completion handlers https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Closures.html or google.

func fetchLocations(completionHandler: (locations: [Location]?, error: NSError) -> ()) -> () {
    var locations : [Location]?
    Alamofire.request(.GET, myURL)
        .responseJSON { response in
            switch response.result {
            case .Success(let data):
               locations = createMapLocations(data)
                completionHandler(locations, error: nil)
            case .Failure(let error):
                print("Request failed with error: \(error)")
                completionHandler(locations: nil, error: error)
            }
    }
}

用法

 fetchLocations(){
        data in
        if(data.locations != nil){
            //do something witht he data
        }else{
            //Handle error here
            print(data.error)
        }

    }

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