在NavigationBar中隐藏和显示返回按钮

Question

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?

Answer 1

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
    };
}