How to add a view as subview for certain controllers - ios

Question

I have multiple storyboards in my app. I want to add a view on always on the top just below the navigation bar for some of the controllers. How Can I achieve this?
I already used navigation delegate and add a view in the window but no luck. Steps to show the gray view in the attached image is.
1. On click of a button on that view controller; a gray view should show and remain on the top of the controllers until all the scanning of the device is not done whether the user should go any of the viewControllers.

Answer 1

You can create a UINavigationController subclass and add the view in it.
class NavigationController: UINavigationController {
let customView = UIView()
let iconImgView = UIImageView()
let msgLbl = UILabel()
override func viewDidLoad() {
super.viewDidLoad()
customView.isHidden = true
customView.translatesAutoresizingMaskIntoConstraints = false
customView.backgroundColor = .gray
view.addSubview(customView)
iconImgView.contentMode = .scaleAspectFit
iconImgView.translatesAutoresizingMaskIntoConstraints = false
customView.addSubview(iconImgView)
msgLbl.numberOfLines = 0
msgLbl.lineBreakMode = .byWordWrapping
msgLbl.textColor = .white
msgLbl.translatesAutoresizingMaskIntoConstraints = false
customView.addSubview(msgLbl)
customView.topAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.topAnchor).isActive = true
customView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
customView.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
iconImgView.widthAnchor.constraint(equalToConstant: 40).isActive = true
iconImgView.heightAnchor.constraint(equalToConstant: 40).isActive = true
iconImgView.centerYAnchor.constraint(equalTo: customView.centerYAnchor).isActive = true
iconImgView.leadingAnchor.constraint(equalTo: customView.leadingAnchor, constant: 15).isActive = true
iconImgView.trailingAnchor.constraint(equalTo: msgLbl.leadingAnchor, constant: 15).isActive = true
msgLbl.topAnchor.constraint(equalTo: customView.topAnchor, constant: 10).isActive = true
msgLbl.bottomAnchor.constraint(equalTo: customView.bottomAnchor, constant: 10).isActive = true
msgLbl.trailingAnchor.constraint(equalTo: customView.trailingAnchor, constant: -15).isActive = true
msgLbl.heightAnchor.constraint(greaterThanOrEqualToConstant: 30).isActive = true
}
func showCustomView(message: String, icon: UIImage) {
msgLbl.text = message
iconImgView.image = icon
customView.isHidden = false
}
func hideCustomView() {
customView.isHidden = true
}
}
Embed all your view controllers in this navigation controller. When you want to show/hide the gray view in a view controller use
Show
(self.navigationController as? NavigationController)?.showCustomView(message: "Any Message", icon: UIImage(named: "anyImage")!)
Hide
(self.navigationController as? NavigationController)?.hideCustomView()
When you push another view controller from the same navigation controller the view won't be hidden until you call the hide method

Answer 2

You can simply create a custom UIView with the relevant frame and call addSubview() on the view you want to add it to.
lazy var customView: UIView = {
let customView = UIView(frame: CGRect.init(x: 0, y: self.view.safeAreaInsets.top, width: UIScreen.main.bounds.width, height: 100))
customView.backgroundColor = .gray
return customView
}()
#IBAction func onTapButton(_ sender: UIButton) {
self.view.addSubview(customView)
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
self.customView.removeFromSuperview()
}
To add it below the navigationBar, use y position of frame as self.view.safeAreaInsets.top. With this your customView will always be aligned below the navigationBar.
You can create the view with the height as per your requirement. I've used height = 100.
Give the correct frame and you can add any view as a subView to another view.