swift 监听网络状态

 func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        
        AFNetworkReachabilityManager.sharedManager().startMonitoring()
        AFNetworkReachabilityManager.sharedManager().setReachabilityStatusChangeBlock { (status) in
            switch status {
            case .Unknown:
                JLToast.makeText("当前网络未知", duration: 3).show(UIApplication.sharedApplication().keyWindow)
            case .NotReachable:
                JLToast.makeText("当前网络不可以用，请检查!", duration: 3).show(UIApplication.sharedApplication().keyWindow)
            case .ReachableViaWiFi:
                break
            case .ReachableViaWWAN:
                break
                
            }
        }
        
      //写你的代码
    
        
        return true
    }

 func applicationDidEnterBackground(application: UIApplication) {
        // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
        // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
        AFNetworkReachabilityManager.sharedManager().stopMonitoring()
    }

    func applicationWillEnterForeground(application: UIApplication) {
        // Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
        AFNetworkReachabilityManager.sharedManager().startMonitoring()
    }