Hide and show back button in navigationBar

I have these two methods:

func showSpinner()
{
    let spinner = UIActivityIndicatorView(activityIndicatorStyle: .White)
    spinner.startAnimating()

    self.navigationItem.leftBarButtonItem = UIBarButtonItem(customView: spinner)
    self.navigationItem.hidesBackButton = true
}

func hideSpinner()
{
    self.navigationItem.leftBarButtonItem = nil
    self.navigationItem.hidesBackButton = false
}

In viewDidLoad I call showSpinner and then after data loaded I call hideSpinner. But backButton often jumping on hideSpinner. How to fix it?

You can use delay to show the back button after removing the spinner. Like 0.2 seconds or as per the requirement

func hideSpinner()
{
    self.navigationItem.leftBarButtonItem = nil
    dispatch_after(1, dispatch_get_main_queue()) { () -> Void in
        self.navigationItem.hidesBackButton = false
    };
}