Get frame height without navigation bar height and tab bar height in deeper view hierarchy

Question

I have a ViewController (B) which is handled by a PageViewController which is inside another ViewController (A) and open it modal. I have centered the ViewController (B) exactly in the middle of the screen. This works fine.

But when I push the ViewController (A) from a NavigationController the frame of ViewController (B) is to big and extends below the NavigationBar and the TabBar. But I want it centered between the NavigationBar and the TabBar.

I know how I can get the height of the navbar and the tabbar so I could resize ViewController (B):

var topBar = self.navigationController?.navigationBar.frame.height
var bottomBar = self.tabBarController?.tabBar.frame.height

But this does not work deep down in the vier hierarchy in ViewController (B). self.navigationController and self.tabBarController are nil. So how can I get the height of the navbar and tabbar deeper down in the view hierarchy? Or do I just have to pass it down from one ViewController to another till I reach ViewController (B)? Or is there another more obvious way to center the view? Thanks.

(I have tried to post screenshots for better understanding but I miss the needed reputation points to post images, sorry)

Solution 1

Use this :

let height = UIApplication.sharedApplication().statusBarFrame.height +
self.navigationController!.navigationBar.frame.height

this support portrait and landscape state.

Swift 5

let height = UIApplication.shared.statusBarFrame.height +
      self.navigationController!.navigationBar.frame.height

Solution 2

For UITabBar, this code work :

self.tabBarController?.tabBar.frame.height

Solution 3

For Swift 3

navBarHeight = (self.navigationController?.navigationBar.intrinsicContentSize.height)! 
+ UIApplication.shared.statusBarFrame.height

Solution 4

As for iOS 13, since the statusBarFrame property of a UIApplication object was deprecated, one can use:

let statusBarHeight =  navigationController?.view.window?.windowScene?.statusBarManager?.statusBarFrame.height ?? 0

let navigationBarHeight = navigationController?.navigationBar.frame.height ?? 0

---

Now, it may seem that doesn't help you @OP since your navigationController is nil, but you could try to use view.window?.windowScene?.statusBarManager?.statusBarFrame.height for the statusBar height and figure out a way to find the navBar height as well? Hope that helps :)

Solution 5

iOS 13 solution:

extension UIViewController {

    /**
     *  Height of status bar + navigation bar (if navigation bar exist)
     */

    var topbarHeight: CGFloat {

        let window = UIApplication.shared.windows.filter {$0.isKeyWindow}.first

        return (window?.windowScene?.statusBarManager?.statusBarFrame.height ?? 0) +
            (self.navigationController?.navigationBar.frame.height ?? 0.0)
    }
}

To call it you can just use: self.topbarHeight in viewController

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