Black Translucent Navigation Bar Opaque Until First Drag - ios

Question

I have an odd situation where I cannot for the life of me get an app to start with the UINavigationBar set to transparent black. The app consists of a UINavigationController with a UIPageViewController as root. These are loaded from a storyboard when the app launches.
The app runs and the UINavigationBar shows up as opaque. As soon as I start dragging the UIPageViewController it triggers some sort of redraw and the UINavigationBar becomes transparent as desired.
I tried a few different ways of setting the UINavigationBar to transparent black, and none of them produced behavior any different than described:
I set these keys in Info.plist:
<key>UIStatusBarTintParameters</key>
<dict>
<key>UINavigationBar</key>
<dict>
<key>Style</key>
<string>UIBarStyleBlack</string>
<key>Translucent</key>
<true/>
</dict>
</dict>
I set the UINavigationBar appearance in the AppDelegate in didFinishLaunchingWithOptions:
UINavigationBar.appearance().tintColor = UIColor.black
UINavigationBar.appearance().isTranslucent = true
I subclassed UINavigationController and set NavigationBar properties in viewDidLoad():
navigationBar.barStyle = .black
navigationBar.isTranslucent = true
navigationBar.setNeedsDisplay()
I set the NavigationBar properties in viewDidLoad() of the UIPageViewController (the navigation controller's root view controller):
navigationController!.navigationBar.barStyle = .black
navigationController!.navigationBar.isTranslucent = true
navigationController!.navigationBar.setNeedsDisplay()
I also tried toggling the navigation bar on / off to trigger a refresh
navigationController!.isNavigationBarHidden = true
navigationController!.isNavigationBarHidden = false
For the sake of completion, I set the navigation bar properties in viewDidLoad() of the child view controller of the UIPageViewController.
In every single case I get the same behavior: opaque bar until I touch the screen and start a drag, at which point it switches to transparent.
What's odd is that setting other attributes of the navigation bar, such as titleTextAttributes, leftButtonItem, and rightButtonItem works just fine and the changes are reflected immediately.

Answer 1

I had a similar requirement with Swift3 an achieved it in this way:
In your view controller which contains PageViewController add the following code in viewDidLoad()
func makeNavigationTranslucent() -> Void {
self.navigationController?.navigationBar.setBackgroundImage(nil, for: .default)
self.navigationController?.navigationBar.shadowImage = nil
self.navigationController?.navigationBar.isTranslucent = true
self.navigationController?.view.backgroundColor = UIColor.clear
self.navigationController?.navigationBar.backgroundColor = UIColor.init(colorLiteralRed: 0.5, green: 0.5, blue: 0.5, alpha: 0.9)
}
Note : Change navigationBar.backgroundColor to the one which you want.
In your storyboard select your controller and under attribute inspector with simulated metrics heading set top bar to Navigation Translucent Bar. Refer below image :

Answer 2

This is kind of a hacky solution, but I managed to get it working by hiding the default navigation bar and adding a new one over it. In the page view controller viewDidLoad() function:
navigationController!.isNavigationBarHidden = true
let newNavBar = UINavigationBar()
newNavBar.barStyle = .black
newNavBar.isTranslucent = true
newNavBar.titleTextAttributes = [NSFontAttributeName: UIFont.mainFontThin(24),
NSForegroundColorAttributeName: UIColor.white]
// etc...
navigationController!.view.addSubview(newNavBar)
newNavBar.frame = CGRect(
x:0, y:0,
width:navigationController!.view.bounds.width,
height:navigationController!.navigationBar.frame.height + UIApplication.shared.statusBarFrame.height
)
newNavBar.pushItem(navigationItem, animated: false)
This shows the translucent navigation bar like we want, but there's still a small problem where the app status bar is black under the translucent nav bar. As before, once you drag a finger the status bar updates to transparent. I'm not sure how to fix this, adding a call to setNeedsStatusBarUpdate() didn't help. So this is a partial fix.