UITapGestureRecognizer works first time, but not second time - swift

Question

[Greatly simplified]
I'm following a "Let's Build That App" YouTube series on Firebase 3. It's from 2016, so I've had to rework some of the code since Swift has evolved since then, but mostly it's a useful tutorial.
But, I'm stuck on something.
The red box is intended to be a custom titleView with an Image and Name, but I've simplified it to try to find the problem.
viewWillAppear calls setupNavbar which sets up the navbar.titleView:
func setupNavbar() {
let titleView = UIView()
titleView.frame = CGRect(x: 0, y: 0, width: 300, height: 40)
titleView.backgroundColor = .red
let containerView = UIView() // for the Image and Label, later
containerView.translatesAutoresizingMaskIntoConstraints = false
containerView.backgroundColor = .green
// left, top, width, height anchors equal to same for titleView
containerView.leftAnchor.constraint(equalTo: titleView.leftAnchor)
// top, width, height are similar
titleView.addSubview(containerView)
self.navigationItem.titleView = titleView
let recognizer = UITapGestureRecognizer(target: self, action: #selector(showChatController))
titleView.addGestureRecognizer(recognizer)
}
The selector's function is:
#objc func showChatController() {
let chatController = ChatLogTableViewController()
navigationController?.pushViewController(chatController, animated: true)
}
The class ChatLogTableViewController has just the default viewDidLoad().
First, I'm surprised the box is red, and not green. Why is that?
Second, if I click the red box, the ChatController is loaded, as expected. But, when I click "Back" and return to this screen, the red box is not visible, thus I can no longer tap on it. BUT....If I sign out and sign in/up again, the box is red and I can click it again.
What am I missing?
Update 1: The "+" creates a new controller and presents it.
present(UINavigationController(
rootViewController: NewMessageTableViewController()),
animated: true,
completion: nil)
That controller is currently empty, except for a leftBarButtonItem which is just a barButtonSystemItem (.cancel). Just like "Sign Out", this also "resets" the gesture and it works.
Update 2: Code added upon request.
Update 3: question greatly simplified. Also, if I change the showChatController code to just print ("show Chat Controller"), I can click to my heart's content; the red box and its tap gesture both remain.
So, there is something happening when I ...pushViewController and then come back.

Answer 1

Have you tried to set isUserInteractionEnabled property of the label which you set as the navBar's titleView? I know it's silly but I've missed this a lot of times :)
let recognizer = UITapGestureRecognizer(target: self, action: #selector(YourViewController.titleWasTapped))
titleView.isUserInteractionEnabled = true
titleView.addGestureRecognizer(recognizer)

Answer 2

you can try following things:
1. "User Interaction Enabled" in the UILabel Attributes Inspector in the Storyboard.
2. override func viewDidLoad(animated: Bool) {
super.viewDidAppear(animated)
self.titleView.userInteractionEnabled = true
var tapGesture = titleView.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(showChatController)))
self.titleView.addGestureRecognizer(tapGesture)
}
func showChatController() {
println("Tap Gesture recognized")
}

Answer 3

Hi #Zonker I've tested your setupNavBar(). It's working fine nothing worng with your code when I press and go back clicking titleView. Reason why you're not getting .green color is you have to give height and width for containerView and big reason is you've put addSubView code below the anchor and there is no .isActive = true in your containerView.leftAnchor.constraint... Please check setupNavBar() code below:
func setupNavbar() {
let titleView = UIView()
titleView.frame = CGRect(x: 0, y: 0, width: 300, height: 40)
titleView.backgroundColor = .red
let containerView = UIView() // for the Image and Label, later
containerView.translatesAutoresizingMaskIntoConstraints = false
containerView.backgroundColor = .green
titleView.addSubview(containerView)
// left, top, width, height anchors equal to same for titleView
containerView.widthAnchor.constraint(equalToConstant: 300).isActive = true
containerView.heightAnchor.constraint(equalToConstant: 40).isActive = true
containerView.leftAnchor.constraint(equalTo: titleView.leftAnchor).isActive = true
// top, width, height are similar
self.navigationItem.titleView = titleView
let recognizer = UITapGestureRecognizer(target: self, action: #selector(showChatController))
titleView.addGestureRecognizer(recognizer)
}
It would better if you push your code in github so we can test your code