How to set the activity indicator in the navigation bar?

Swift Code:

let activityIndicator = UIActivityIndicatorView(frame: CGRect(x: 0, y: 0, width: 20, height: 20))
let barButton = UIBarButtonItem(customView: activityIndicator)
self.navigationItem.setRightBarButton(barButton, animated: true)
activityIndicator.startAnimating()

You are creating a new activity indicator view here, which is fine, but you are not referring to the activity indicator in the status bar.

To show the activity indicator in the status bar, simply call this:

[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];

I add the below piece of code in the view where i wanted the activity indicator in the navigation bar.

activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
UIBarButtonItem * barButton = [[UIBarButtonItem alloc] initWithCustomView:activityIndicator];
[self navigationItem].rightBarButtonItem = barButton;
[activityIndicator startAnimating];