How to check internet connection on iOS device? [duplicate]

Answer 1

Updated answer for Swift 4.0 & AlamoFire:

The answer I posted on Sept 18 is incorrect, it only detects if it is connected to network, not internet. Here is the correct solution using AlamoFire:

1) Create custom Reachability Observer class:

import Alamofire

class ReachabilityObserver {

    fileprivate let reachabilityManager = NetworkReachabilityManager()
    fileprivate var reachabilityStatus: NetworkReachabilityManager.NetworkReachabilityStatus = .unknown

    var isOnline: Bool {
        if (reachabilityStatus == .unknown || reachabilityStatus == .notReachable){
            return false
        }else{
            return true
        }
    }

    static let sharedInstance = ReachabilityObserver()
    fileprivate init () {
        reachabilityManager?.listener = {
            [weak self] status in

            self?.reachabilityStatus = status
            NotificationCenter.default.post(
                name: NSNotification.Name(rawValue: ClickUpConstants.ReachabilityStateChanged),
                object: nil)
        }
        reachabilityManager?.startListening()
    }
}

2) Initialize on app start up

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
     _ = ReachabilityObserver.sharedInstance
     return true
}

3) Use this anywhere in your app to detect if online, such as in view did load, or when action occurs

if (ReachabilityObserver.sharedInstance.isOnline){
    //User is online
}else{
    //User is not online
}