如何检测 iPhone 是否刚刚连接到互联网？

Question

一旦设备连接到 wifi，我需要在我的应用中做一些事情。这不是关于“它是否连接到 wifi？”，而是“告诉我设备何时连接到 wifi，而之前它处于离线状态？”

换句话说，当 iPhone 以任何方式连接到互联网时，我需要响应事件。

是否可以使用AFNetworking 或自定义 API？

Answer 1

您可以使用Reachability。

在示例代码中你会发现：

import UIKit

let useClosures = false

class ViewController: UIViewController {

    @IBOutlet weak var networkStatus: UILabel!

    let reachability = Reachability.reachabilityForInternetConnection()

    override func viewDidLoad() {
        super.viewDidLoad()

        if (useClosures) {
            reachability?.whenReachable = { reachability in
                self.updateLabelColourWhenReachable(reachability)
            }
            reachability?.whenUnreachable = { reachability in
                self.updateLabelColourWhenNotReachable(reachability)
            }
        } else {
            NSNotificationCenter.defaultCenter().addObserver(self, selector: "reachabilityChanged:", name: ReachabilityChangedNotification, object: reachability)
        }

        reachability?.startNotifier()

        // Initial reachability check
        if let reachability = reachability {
            if reachability.isReachable() {
                updateLabelColourWhenReachable(reachability)
            } else {
                updateLabelColourWhenNotReachable(reachability)
            }
        }
    }

    deinit {

        reachability?.stopNotifier()

        if (!useClosures) {
            NSNotificationCenter.defaultCenter().removeObserver(self, name: ReachabilityChangedNotification, object: nil)
        }
    }

    func updateLabelColourWhenReachable(reachability: Reachability) {
        if reachability.isReachableViaWiFi() {
            self.networkStatus.textColor = UIColor.greenColor()
        } else {
            self.networkStatus.textColor = UIColor.blueColor()
        }

        self.networkStatus.text = reachability.currentReachabilityString
    }

    func updateLabelColourWhenNotReachable(reachability: Reachability) {
        self.networkStatus.textColor = UIColor.redColor()

        self.networkStatus.text = reachability.currentReachabilityString
    }


    func reachabilityChanged(note: NSNotification) {
        let reachability = note.object as! Reachability

        if reachability.isReachable() {
            updateLabelColourWhenReachable(reachability)
        } else {
            updateLabelColourWhenNotReachable(reachability)
        }
    }
}

Answer 2

AFNetworking 的简单用法：

1. 添加观察者：

   NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("networkDidChangeStatus"), name: AFNetworkingReachabilityDidChangeNotification, object: nil)
   

2. 实现自定义Selector:

   func networkDidChangeStatus() {
   
       if AFNetworkReachabilityManager.sharedManager().reachable {
           print("connected")
       } else {
           print("disconnected")
       }
   }
   

3. 开始监控：

   AFNetworkReachabilityManager.sharedManager().startMonitoring()