Swift 3 Reachability From Button

Question

I am using the Reachability library on github found here. I want to check whether device is online by clicking on a button. I am new to Reachability so from what I have seen, you have to start listening for the change and then test the connection and then stop listening. So far I have this in my button action but when I click the button, nothing gets printed to console.

var reachability: Reachability!
do {
    try reachability?.startNotifier()
} catch {
    print("Unable to start notifier")
}


reachability?.whenReachable = { reachability in

    DispatchQueue.main.async {
        if reachability.isReachableViaWiFi {
            print("Reachable via WiFi")
        } else {
            print("Reachable via Cellular")
        }
    }
}


reachability?.whenUnreachable = { reachability in

    DispatchQueue.main.async {
        print("Not reachable")
    }
}


reachability?.stopNotifier()

Answer 1

You got nil because of using implicitly unwrapped optional.

Replace,

var reachability: Reachability!

to

let reachability = Reachability()

Try below,

let reachability = Reachability()

do {
    try reachability?.startNotifier()
} catch {
    print("Unable to start notifier")
}


if reachability?.isReachable == true{

    if reachability?.isReachableViaWiFi == true{
        print("Reachable via WiFi")
    } else if reachability?.isReachableViaWWAN == true{
        print("Reachable via WWAN simulator")
    }else{
        print("Reachable via Cellular")
    }

}else{
    print("Not reachable")
}


reachability?.stopNotifier()