swift3 - How to make a Navigation Bar and Status Bar blurred (UIBlurEffect)? iOS, Swift 3

Question

How to make the Navigation Bar and Status Bar blurred (UIBlurEffect)? When I'm by clicking on the image to scroll down (Scroll View) to other pictures, this picture (in this case with a white machine) is simply lost under the Navigation Bar, and it is necessary that this figure would be visible under the Navigation Bar with effect UIBlurEffect.

NO UIBlurEffect

I have tried so, but did not work:

func addBlurEffect() {
// Add blur view
let bounds = self.navigationController?.navigationBar.bounds as CGRect!
let visualEffectView = UIVisualEffectView(effect: UIBlurEffect(style: .light))
visualEffectView.frame = bounds!
visualEffectView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
self.navigationController?.navigationBar.addSubview(visualEffectView)
self.navigationController?.navigationBar.sendSubview(toBack: visualEffectView)
visualEffectView.isUserInteractionEnabled = false }

Firstly, when scrolling the picture just disappears under the Navigation Bar.
Second, Status Bar remains gray.

Bad UIBlurEffect for NavigationBar, and NO UIBlurEffect for StatusBar

In order to Status Bar not remain gray, I tried to do it, but to no avail =(

bounds.offsetBy(dx: 0.0, dy: -20.0)
bounds.size.height = bounds.height + 20.0

Also in AppDelegate (he application written in Objective-C) in didFinishLaunchingWithOptions, I tried to add it all remains the same without any changes:

[[UINavigationBar appearance] setBackgroundImage:[[UIImage alloc]init] forBarMetrics:UIBarMetricsDefault];
[[UINavigationBar appearance] setShadowImage:[[UIImage alloc]init]];
[[UINavigationBar appearance] setBackgroundColor:[UIColor colorWithRed:0.0f green:0.0f blue:0.0f alpha:0.0f]];
[[UINavigationBar appearance] setTranslucent:YES];

Please help solve the problem, I mess around with it for 3 days.
Sorry for my bad English.

Answer 1

Setting the background image to the navigation bar does the trick. In swift 3 the below code works for me.

    let visualEffectView   = UIVisualEffectView(effect: UIBlurEffect(style: .light))
    visualEffectView.frame =  (self.navigationController?.navigationBar.bounds.insetBy(dx: 0, dy: -10).offsetBy(dx: 0, dy: -10))!
    self.navigationController?.navigationBar.isTranslucent = true
    self.navigationController?.navigationBar.setBackgroundImage(UIImage(), for: .default)
    self.navigationController?.navigationBar.addSubview(visualEffectView)

output: