Valid way to hide QLPreviewController RightBarButtonItem/RightBarButtonItems Xamarin iOS - ios8

Question

My app supports iOS8+ devices. I want to hide right Action button from navigation bar. By research I found following few workarounds:
1. Create Sub class of QLPreviewController and in ViewDidAppear SetRightBarButtonItems to zero.
public class PdfViewController : QLPreviewController
{
public override void ViewDidAppear (bool animated)
{
base.ViewDidAppear (animated);
NavigationItem.SetRightBarButtonItems (new UIKit.UIBarButtonItem[0], false);
}
}
In this case problem is RightBarButtonItem appears and then disappears. In mean while user is able to click on that RightBarButtonItem button. I don't want this behavior.
2. Create UIViewController and add QLPreviewController as child ViewController.
void BtnShowPdf_Clicked (object sender, EventArgs e) {
var dummyVC = new UIViewController ();
var pdfVC = new PdfViewController ();
dummyVC.AddChildViewController (pdfVC);
dummyVC.View.AddSubview (pdfVC.View);
dummyVC.NavigationItem.SetRightBarButtonItems (new UIBarButtonItem[0], false);
dummyVC.EdgesForExtendedLayout = UIRectEdge.None;
dummyVC.AutomaticallyAdjustsScrollViewInsets = false;
dummyVC.View.BackgroundColor = UIColor.Clear;
pdfVC.EdgesForExtendedLayout = UIRectEdge.None;
pdfVC.AutomaticallyAdjustsScrollViewInsets = false;
pdfVC.View.BackgroundColor = UIColor.Clear;
}
In this case If I set QLPreviewController it works as expected. But NavigationBar becomes more darker than default ViewController background color.
Dark Bar:
http://screencast.com/t/bqVMv5qqGz
Needed clear background bar like:
http://screencast.com/t/MUwE2VnxJ7
My questions are:
A) I would like to know which is the correct way to hide right
navigation bar button as per Apple guidelines ? If you have correct
solution then those are also appreciated.
B) Also Can you please suggest solution(s) for #1 Or #2 ?

Answer 1

Pretty sure you can do this:
override func viewWillAppear(_ animated: Bool)
{
super.viewWillAppear(animated)
self.navigationItem.rightBarButtonItems = nil
}