Checking network status in Swift, observer does not get called

Question

I have imported Reachability.h .m files like written here into my Swift project, but observer / event handler will not get called after start, why?

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: NSDictionary?) -> Bool {

    NSNotificationCenter.defaultCenter().addObserver(self, selector: "reachabilityChanged:", name: kReachabilityChangedNotification, object: nil)

    let hostReachability = Reachability(hostName: "www.apple.com");
    hostReachability.startNotifier();

    return true
}

func reachabilityChanged(note: NSNotification) { // <- DOES NOT GET CALLED

    let reachability: Reachability = note.object as Reachability;

    if(reachability.currentReachabilityStatus() != .NotReachable) {

    }
}

Its a problem in your Reachability class, Try this one https://github.com/tonymillion/Reachability — Yatheesha, Jul 02 '14 at 09:02
is it an iOS8 / Swift related fix? because the same Reachability.h .m was working for iOS7 / Objective-C — János, Jul 02 '14 at 09:22
Reachability object is deallocated (since it is an autoreleased object and also not holding strong reference) — Yatheesha, Jul 02 '14 at 09:57
This might be of use… https://github.com/ashleymills/Reachability.swift — Ashley Mills, Dec 02 '14 at 11:44

score 12 · Accepted Answer · edited Feb 15 '16 at 07:49

The Reachability object returned is an autoreleased object , so it has deallocated hence notification is not triggering . You can fix by keeping a strong reference to it.

create a property to hold Reachability object

var reachability:Reachability?

 func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: NSDictionary?) -> Bool {
        // Override point for customization after application launch.

        NSNotificationCenter.defaultCenter().addObserver(self, selector: "reachabilityChanged:", name:kReachabilityChangedNotification, object: nil)

        reachability = Reachability(hostName: "www.apple.com");
        reachability?.startNotifier();

        return true
    }

This will fix your problem.

The observer's name is changed from ReachabilityChangedNotification to kReachabilityChangedNotification. Notice the "k"

Sorry, it doesn't work. "reachabilityChanged" is still never called. — Makalele, Jun 16 '15 at 21:02

score 0 · Answer 2 · answered Jul 07 '15 at 03:57

As mentioned in other answers, you need to maintain a strong reference to the Reachability object. If you aren't checking a particular host, then call reachabilityForInternetConnection:

let internetReachability = Reachability.reachabilityForInternetConnection()

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {

    // Override point for customization after application launch.

    NSNotificationCenter.defaultCenter().addObserver(self, selector: "reachabilityChanged:", name: kReachabilityChangedNotification, object: internetReachability)
    internetReachability.startNotifier()
    let hasInternet = internetReachability.currentReachabilityStatus().value == 0 ? false : true

    // Save to user defaults, log to console, etc.

    return true
}

func reachabilityChanged(note: NSNotification) {
    var hasInternet = Bool()
    if let reachability = note.object as? Reachability {
        hasInternet = internetReachability.currentReachabilityStatus().value == 0 ? false : true
    }

    // Update user defaults, log to console, show error message, etc.
}

Though its late for me to answer your reachability import doubt @EladBenda.But anyway,for working with Reachability.h and .m files in swift.You have to use bridging header file in swift. — Manish Singh, Apr 10 '16 at 16:22

score 0 · Answer 3 · answered Sep 27 '17 at 09:26

For iOS 3+, use below code:

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    NotificationCenter.default.addObserver(self, selector: #selector(checkForReachability(notification:)), name: NSNotification.Name.reachabilityChanged, object: nil)
    reachability = Reachability.forInternetConnection()
    reachability.startNotifier()

    return true
}

 // MARK:
// MARK: Check Internet Status
func checkForReachability(notification:NSNotification)
{
    let networkReachability = notification.object as! Reachability;
    let remoteHostStatus = networkReachability.currentReachabilityStatus()

    if (remoteHostStatus == NotReachable)
    {
        print("Not Reachable")
    }
    else
    {
        print("Reachable")
    }
}

Checking network status in Swift, observer does not get called

3 Answers3