Using UIView (Singleton) on different viewcontrollers - ios

Question

I have a UIView which have a button and some view to indicate sucess and failure. I am trying to use that UIView on other view controllers and receive the button action on called view controllers.
This is what i have tried so far
protocol FailViewDelegate: class {
func tryAgainTapped()
}
class AlertView: UIView {
static let instance = AlertView()
weak var delegate : FailViewDelegate?
#IBOutlet weak var titleLbl: UILabel!
#IBOutlet weak var messageLbl: UILabel!
#IBOutlet weak var dashIMageView: AnimatableImageView!
#IBOutlet weak var circleView: AnimatableView!
#IBOutlet weak var iconStatus: AnimatableImageView!
#IBOutlet weak var tryAgainButton: AnimatableButton!
#IBOutlet weak var parentView: UIView!
private override init(frame: CGRect) {
super.init(frame: frame)
commonInit()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
commonInit()
}
private func commonInit() {
Bundle.main.loadNibNamed("AlertView", owner: self, options: nil)
}
enum AlertType {
case success
case failure
}
func showAlert(alertType: AlertType, to: UIViewController) {
switch alertType {
case .success:
dashIMageView.image = UIImage(named: "circle-dash-blue")
circleView.backgroundColor = UIColor(hexString: "#4EBFFF")
titleLbl.text = "Success"
titleLbl.textColor = UIColor(hexString: "#4EBFFF")
messageLbl.text = "Your ticket has been created."
tryAgainButton.isHidden = true
iconStatus.image = UIImage(named: "icon-check")
case .failure:
dashIMageView.image = UIImage(named: "circle-dash-red")
circleView.backgroundColor = UIColor(hexString: "#EB3708")
titleLbl.text = "Failure"
titleLbl.textColor = UIColor(hexString: "#EB3708")
messageLbl.text = "There was an error, creating your ticket."
tryAgainButton.isHidden = false
iconStatus.image = UIImage(named: "icon-close")
}
parentView.center = to.view.center
to.view.addSubview(parentView)
}
func dismissAlert() {
parentView.removeFromSuperview()
}
#IBAction func tryAgainButtonTapped(_ sender: AnimatableButton) {
delegate?.tryAgainTapped()
}
}
This is how i have called the view
class CreateTicketViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
AlertView.sharedInstance.delegate = self
}
#IBAction func createTicketTapped(_ sender: AnimatableButton) {
AlertView.sharedInstance.showAlert(alertType: .failure, to: self)
}
}
extension CreateTicketViewController : FailViewDelegate {
func tryAgainTapped() {
print("Try Again Tapped")
}
}
This is the error that i got
Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value
(in dashIMageView.image = UIImage(named: "circle-dash-red")) and when i remove the dashImageView then the error occur for nextView and so on

Answer 1

You don't need to make it a singleton, which in this case (View) is a very uncommon approach, I think. You can create as many instances of that view as you want any time, anywhere (on other ViewControllers) you want and specify them, the way you want them to have.
When you want a view to be rendered and be visible, it always must be part of the view hierarchy in the current visible view controllers main view. And a view can only have ONE SUPERVIEW at the time, so whenever you add a (singleton) view to another superview, it will be removed from an other superview. If you want the same view on many view controllers (no problem), just don't let it be a singleton.
So first thing to do -> Remove the singleton design by commenting out that line:
class AlertView: UIView {
// make this line a comment or just remove it
// static let instance = AlertView()
weak var delegate : FailViewDelegate?
In your different view controllers you just create that instances of your AlertView and set the delegate correctly like this:
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
myAlertView = AlertView()
myAlertView.delegate = self
// then you don't need this anymore
// AlertView.sharedInstance.delegate = self
}