UIAlert error, whose view is not in the window hierarchy

Question

I am working on my network connectivity,

I put checking reachability code in viewDidLoad, so that I notify User by alerting if there is not network.

Here is my code for this,

class ViewController: UIViewController {
var reachability : Reachability?

override func viewDidLoad() {
    super.viewDidLoad()
    if reachability?.isReachable() == true
     {
         print("reachable")
     }else{

        let myAlert = UIAlertController(title: "No network", message:
            "Your network is not working", preferredStyle:
            UIAlertControllerStyle.Alert)
        let okAction = UIAlertAction(title: "Ok", style:
            UIAlertActionStyle.Default, handler: nil)
        myAlert.addAction(okAction)
        self.presentViewController(myAlert, animated: true, completion:
            nil)

    }

but If I try on my simulator or cellphone, it shows error message that

2015-11-08 16:43:52.173 PracticeReachability[5494:2661290] Warning: Attempt to present on whose view is not in the window hierarchy!

I tried put

var myAlert = UIAlertController()

and var myAlert :UIAlertController!

both doesn't make it work.

Question

My other Alerts work fine in same ViewController. Why only this is not working?

And How can I make it work?

Answer 1

I don't think the view controller's view has been added to the screen yet in viewDidLoad. Try moving your code to viewDidAppear.