带有 dataTask 返回值的函数 [英] function with dataTask returning a value

问题描述

我不想检查我的 url statusCode 是否等于 200，如果 statusCode 等于 200，我创建了一个返回布尔值的函数，我正在使用 dataTask，但我不知道如何返回一个值:

I wan't to check if my url statusCode equals to 200, I created a function returning a Boolean if the statusCode equals to 200, I'm using a dataTask, but I don't know how to return a value:

class func checkUrl(urlString: String) -> Bool{

    let urlPath: String = urlString
    var url: NSURL = NSURL(string: urlPath)!
    var request: NSURLRequest = NSURLRequest(url: url as URL)
    var response: URLResponse?

    let session = Foundation.URLSession.shared


    var task = session.dataTask(with: request as URLRequest, completionHandler: {(data, response, error) in
        if let error = error {
            print(error)
        }

        if let data = data{
            print("data =\(data)")
        }
        if let response = response {
            print("url = \(response.url!)")
            print("response = \(response)")
            let httpResponse = response as! HTTPURLResponse
            print("response code = \(httpResponse.statusCode)")

            if httpResponse.statusCode == 200{
                return true
            } else {
                return false
            }
        }
    })
    task.resume()
}

if else 中的返回是返回错误:

The returns in if else are returning an error:

void 函数中出现意外的非 void 返回值

Unexpected non-void return value in void function

推荐答案

为了返回值，你应该使用块.尝试像这样声明你的函数:

in order to return value you should use blocks. Try declaring your function like this:

class func checkUrl(urlString: String, finished: ((isSuccess: Bool)->Void) {

    let urlPath: String = urlString
    var url: NSURL = NSURL(string: urlPath)!
    var request: NSURLRequest = NSURLRequest(url: url as URL)
    var response: URLResponse?

    let session = Foundation.URLSession.shared


    var task = session.dataTask(with: request as URLRequest, completionHandler: {(data, response, error) in
        if let error = error {
            print(error)
        }

        if let data = data{
            print("data =\(data)")
        }
        if let response = response {
            print("url = \(response.url!)")
            print("response = \(response)")
            let httpResponse = response as! HTTPURLResponse
            print("response code = \(httpResponse.statusCode)")

            if httpResponse.statusCode == 200{
                finished(isSuccess: true)                
            } else {
                finished(isSuccess: false) 
            }
        }
    })
    task.resume()
}

然后这样称呼它:

checkUrl("http://myBestURL.com", finished { isSuccess in
// Handle logic after return here
})

希望这会有所帮助.

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