我正在按照下面的代码复制和转换自堆栈溢出问题。

我正在获得互联网速度，但我不确定，如果我做的是正确的。

import UIKit

class ViewController: UIViewController, NSURLConnectionDataDelegate{
var connection:NSURLConnection!
var length:Int!
var startTime:NSDate!

//let kMinimumMegabytesPerSecond: CGFloat = 1

let kMaximumElapsedTime: CGFloat = 2.0



override func viewDidLoad() {
    super.viewDidLoad()
    self.testDownloadSpeed()
    // Do any additional setup after loading the view, typically from a nib.
}

func testDownloadSpeed() {
    var url: NSURL = NSURL(string: "http://thewallpaperhost.com/wp-content/uploads/2014/12/wallpapers-hd-8000-8331-hd-wallpapers.jpg")!
    var request: NSURLRequest = NSURLRequest(URL: url)
    self.startTime = NSDate()
    self.length = 0
    self.connection = NSURLConnection(request: request, delegate: self)
    self.connection.start()
    let delayInSeconds:Int64 =  1000000000  * 2
    var popTime:dispatch_time_t = dispatch_time(DISPATCH_TIME_NOW, (Int64)(delayInSeconds ))
    dispatch_after(popTime, dispatch_get_main_queue(), {() -> Void in
       if let conn = self.connection {
            self.connection.cancel()
            self.connection = nil
            self.useOffline()
        }
    })
}

func determineMegabytesPerSecond() -> CGFloat {
    var elapsed: NSTimeInterval
    if (startTime != nil) {
        elapsed = NSDate().timeIntervalSinceDate(startTime)
        var d =  (Double(length) / elapsed)
        var result = CGFloat( d/1024)
        result = result * 0.0078125
        result = result * 0.0009765625
        return result

    }
    return -1
}

func useOnline() {
     NSLog("Successful")
     NSLog("\(determineMegabytesPerSecond())")

}

func useOffline() {

    NSLog("UnSuccessful")
    NSLog("\(determineMegabytesPerSecond())")
}

func connection(connection: NSURLConnection, didReceiveResponse response: NSURLResponse) {
    NSLog("data came")
    self.startTime = NSDate()
}


func connection(connection: NSURLConnection, didFailWithError error: NSError) {
    if let conn = self.connection {
        self.connection = nil
        useOffline()
    }
}


func connectionDidFinishLoading(connection: NSURLConnection) {
    self.connection = nil

    useOnline()
}

func connection(connection: NSURLConnection, didReceiveData data: NSData) {
    self.length  = self.length +  data.length
    NSLog("\(data.length)")
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

}

我从下面的 URL 复制了代码。它在 Objective C 中，所以我转换了代码!

How to detect Network Signal Strength in iOS Reachability

最佳答案

您的代码片段取自 this answer .我已将其更新为使用 URLSession。 Swift 版本如下:

class ViewController: UIViewController {
    var startTime: CFAbsoluteTime!
    var bytesReceived: Int = 0
    var speedTestCompletionHandler: ((Result<Double, Error>) -> Void)?

    override func viewDidLoad() {
        super.viewDidLoad()

        testDownloadSpeed(timeout: 5) { result in
            switch result {
            case .failure(let error):              print(error)
            case .success(let megabytesPerSecond): print(megabytesPerSecond)
            }
        }
    }

    /// Test speed of download
    ///
    /// Test the speed of a connection by downloading some predetermined resource. Alternatively, you could add the
    /// URL of what to use for testing the connection as a parameter to this method.
    ///
    /// - parameter timeout:             The maximum amount of time for the request.
    /// - parameter completionHandler:   The block to be called when the request finishes (or times out).
    ///                                  The error parameter to this closure indicates whether there was an error downloading
    ///                                  the resource (other than timeout).
    ///
    /// - note:                          Note, the timeout parameter doesn't have to be enough to download the entire
    ///                                  resource, but rather just sufficiently long enough to measure the speed of the download.

    func testDownloadSpeed(timeout: TimeInterval, completionHandler: @escaping (Result<Double, Error>) -> Void) {
        let url = URL(string: "https://insert.your.site.here/yourfile")!

        startTime = CFAbsoluteTimeGetCurrent()
        bytesReceived = 0
        speedTestCompletionHandler = completionHandler

        let configuration = URLSessionConfiguration.ephemeral
        configuration.timeoutIntervalForResource = timeout
        let session = URLSession(configuration: configuration, delegate: self, delegateQueue: nil)
        session.dataTask(with: url).resume()
        session.finishTasksAndInvalidate()
    }
}

extension ViewController: URLSessionDataDelegate {
    func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive data: Data) {
        bytesReceived += data.count
    }
}

extension ViewController: URLSessionDelegate {
    func urlSession(_ session: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) {
        let stopTime = CFAbsoluteTimeGetCurrent()
        let elapsed = stopTime - startTime
        guard elapsed != 0 && (error == nil || (error as? URLError)?.code == .timedOut) else {
            speedTestCompletionHandler?(.failure(error ?? URLError(.unknown)))
            return
        }

        let speed = elapsed != 0 ? Double(bytesReceived) / elapsed / 1024.0 / 1024.0 : -1
        speedTestCompletionHandler?(.success(speed))
    }
}

关于ios - 在 iOS 8 中确定互联网速度的正确方法，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/33887748/