Prevent UINavigationBar animation in custom container

Question

I followed this guide Implementing a Container View Controller to make a container that would handle login/logout in the app.

Children view controllers are: UINavigationController for login, and UITabBarController for the rest of the app:

My problem is that UINavigationBar animates strangely, and I want to prevent its animation:

The animation code is basically this (full project code here):

    let current = childViewControllers.first
    current?.willMoveToParentViewController(nil)

    child.securityContainer = self
    addChildViewController(child)

        child.view.frame = newChildOriginFrame

        UIView.transitionWithView(view, duration: 0.3, options: [], animations: {

            child.view.frame = newChildTargetFrame
            current?.view.frame = oldChildTargetFrame

            self.view.addSubview(child.view)

        }, completion: { _ in

            child.didMoveToParentViewController(self)
            current?.view.removeFromSuperview()
            current?.removeFromParentViewController()
            current?.securityContainer = nil
        })

How can I prevent animation of UINavigationBar?

Answer 1

Fixed it by moving addSubview outside animations block:

let current = childViewControllers.first
current?.willMoveToParentViewController(nil)

child.securityContainer = self
addChildViewController(child)

    child.view.frame = newChildOriginFrame

    view.addSubview(child.view)

    UIView.transitionWithView(view, duration: 0.3, options: [], animations: {

        child.view.frame = newChildTargetFrame
        current?.view.frame = oldChildTargetFrame

    }, completion: { _ in

        child.didMoveToParentViewController(self)
        current?.view.removeFromSuperview()
        current?.removeFromParentViewController()
        current?.securityContainer = nil
    })

(full project source code)