Search bar gets removed from the view hierarchy after custom transition - ios

Question

I have two view controllers embedded into a UINavigationController. The first view controller has a UISearchController set to its navigation item. Here is the full code where I configure the search controller:
private func configureSearchController() {
searchController.searchResultsUpdater = self
searchController.obscuresBackgroundDuringPresentation = false
searchController.hidesNavigationBarDuringPresentation = false
//searchController.dimsBackgroundDuringPresentation = false
searchController.searchBar.tintColor = .white
searchController.searchBar.delegate = self
//White search text
UITextField.appearance(whenContainedInInstancesOf: [UISearchBar.self]).defaultTextAttributes = [NSAttributedStringKey.foregroundColor.rawValue: UIColor.white]
//White placeholder
UITextField.appearance(whenContainedInInstancesOf: [UISearchBar.self]).attributedPlaceholder = NSAttributedString(string: NSLocalizedString("Search", comment: "search bar placeholder"), attributes: [NSAttributedStringKey.foregroundColor: UIColor.white])
//searchController.searchBar.sizeToFit()
navigationItem.searchController = searchController
navigationItem.hidesSearchBarWhenScrolling = false
navigationController?.navigationBar.prefersLargeTitles = false
//
definesPresentationContext = true
}
I call this method from viewDidLoad.
As mentioned in the question title, I use a navigation controller custom transition. Here is the transition animator's full code.
class RevealViewControllerAnimator: NSObject, UIViewControllerAnimatedTransitioning {
private let animationDuration = 1.5
var operation: UINavigationControllerOperation = .push
var isShowing = true
private weak var storedContext: UIViewControllerContextTransitioning?
var snapshot: UIView?
private lazy var viewOnTopOfSnapshot: UIView? = {
let view = UIView()
view.frame = self.snapshot!.frame
if isShowing {
view.backgroundColor = .clear
} else {
view.backgroundColor = UIColor(white: 0.3, alpha: 0.4)
}
return view
}()
private var backgroundViewBackgroundDarkColor = UIColor(white: 0.2, alpha: 0.4)
func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
return animationDuration
}
func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
storedContext = transitionContext
print ("OPERATION", operation.rawValue)
//If we are presenting a view controller
if isShowing {
let fromVC = transitionContext.viewController(forKey: .from) as! ViewController1
let toVC = transitionContext.viewController(forKey: .to) as! ViewController2
snapshot = UIApplication.shared.keyWindow?.snapshotView(afterScreenUpdates: false)
let containerView = transitionContext.containerView
//Adding a view on top of a snapshot and animating its bacground color
if let snapshot = snapshot, let viewOnTopOfSnapshot = viewOnTopOfSnapshot {
containerView.addSubview(self.snapshot!)
containerView.insertSubview(viewOnTopOfSnapshot, aboveSubview: snapshot)
UIView.animate(withDuration: animationDuration - 1.0, animations: {
viewOnTopOfSnapshot.backgroundColor = self.backgroundViewBackgroundDarkColor
}, completion: nil)
}
containerView.addSubview(toVC.view)
toVC.view.frame = transitionContext.finalFrame(for: toVC)
animate(toView: toVC.view, fromTriggerButton: fromVC.filterButton)
} else {
//If we are dismissing the view controller
let fromVC = transitionContext.viewController(forKey: .from) as! ViewController2
let toVC = transitionContext.viewController(forKey: .to) as! ViewController1
let containerView = transitionContext.containerView
//Animating the background color change to clear
if let viewOnTopOfSnapshot = viewOnTopOfSnapshot {
UIView.animate(withDuration: animationDuration, animations: {
viewOnTopOfSnapshot.backgroundColor = .clear
}, completion: {_ in
self.snapshot?.removeFromSuperview()
viewOnTopOfSnapshot.removeFromSuperview()
})
}
//containerView.addSubview(fromVC.view)
containerView.insertSubview(toVC.view!, belowSubview: snapshot!)
animateDismisss(fromView: fromVC.view, toTriggerButton: fromVC.saveButton)
}
}
//MARK: Animation for pushing
private func animate(toView: UIView, fromTriggerButton button: UIButton) {
let rect = CGRect(x: toView.frame.maxX, y: toView.frame.minY, width: button.frame.width, height: button.frame.height)
let circleMaskPathInitial = UIBezierPath(ovalIn: rect)
let fullHeight = toView.bounds.height
let extremePoint = CGPoint(x: button.center.x, y: button.center.y - fullHeight)
let radius = sqrt((extremePoint.x * extremePoint.x) + (extremePoint.y * extremePoint.y))
let circleMaskPathFinal = UIBezierPath(ovalIn: button.frame.insetBy(dx: -radius - 1000, dy: -radius - 1000))
let maskLayer = CAShapeLayer()
maskLayer.path = circleMaskPathFinal.cgPath
toView.layer.mask = maskLayer
let maskLayerAnimation = CABasicAnimation(keyPath: "path")
maskLayerAnimation.fromValue = circleMaskPathInitial.cgPath
maskLayerAnimation.toValue = circleMaskPathFinal.cgPath
maskLayerAnimation.duration = animationDuration
maskLayerAnimation.delegate = self
maskLayer.add(maskLayerAnimation, forKey: "path")
}
//MARK: Animation for pop (dismiss)
private func animateDismisss(fromView: UIView, toTriggerButton button: UIButton) {
let rect = CGRect(x: button.frame.origin.x, y: button.frame.midY, width: button.frame.width, height: button.frame.width)
let finalCircleMaskPath = UIBezierPath(ovalIn: rect)
let fullHeight = fromView.bounds.height
let extremePoint = CGPoint(x: button.center.x, y: button.center.y - fullHeight)
let radius = sqrt((extremePoint.x * extremePoint.x) + (extremePoint.y * extremePoint.y))
let initialCircleMaskPath = UIBezierPath(ovalIn: button.frame.insetBy(dx: -radius, dy: -radius))
let maskLayer = CAShapeLayer()
maskLayer.path = finalCircleMaskPath.cgPath
fromView.layer.mask = maskLayer
let maskLayerAnimation = CABasicAnimation(keyPath: "path")
maskLayerAnimation.fromValue = initialCircleMaskPath.cgPath
maskLayerAnimation.toValue = finalCircleMaskPath.cgPath
maskLayerAnimation.duration = 0.8
maskLayerAnimation.delegate = self
maskLayer.add(maskLayerAnimation, forKey: "path")
}
extension RevealFilterViewControllerAnimator : CAAnimationDelegate {
func animationDidStop(_ anim: CAAnimation, finished flag: Bool) {
if let context = storedContext {
storedContext?.completeTransition(!context.transitionWasCancelled)
} else {
storedContext = nil
}
}
}
So, in two words, I get a snapshot of the ViewController1, insert it to the containerView, and on top of it, insert another view which background color I change during the animation. When popping, I get rid of the snapshot and the view, and also insert the ViewController1's view to a containerView.
As I mentioned in the beginning of the question, I have a UISearchController with a search bar in the first view controller.
The problem is, after dismissing the ViewController2 the search controller gets removed from the hierarchy and I get a blank white space. Here is the demonstration for that:
When I print the UISearchController or the search bar on the console, I get the object information, however, as you can see, it disappears from the view hierarchy (In a view hierarchy debugger I can't find it).
Why is this happening, and how this could be solved?

Answer 1

Finally, I figured out what was causing the issue, and once I did, the solution was quite simple. So, the reason why that was happening was that in the ViewController2's viewDidLoad method I was hiding the navigation bar, but I never set it back when popping the view controller.
So, here is the code that I use for the navigation bar in the second view controller (my view controllers look a little bit different but the logic is the same):
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
navigationController?.setNavigationBarHidden(true, animated: false)
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
navigationController?.setNavigationBarHidden(false, animated: true)
}
Here is how the animation looking right now (I know, there are some rough edges here, but at least, the problem is solved).