Pass Data From View Controller to View in MVC - Swift - ios

Question

Passing data between UIViewControllers is fairly straightforward, but passing data from a controller to a view is something I can't seem to figure out.
In my specific case the user taps on an "event" cell, and transitions into a detailed view.
How do I pass the "event" from the tapped cell, to the detail view?
// Inside Starting View Controller
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let vc = EventDetailController()
let vcView = vc.view as! EventDetailView
vcView.event = model.events[indexPath.item]
navigationController?.pushViewController(vc, animated: true)
}
// Second View
class EventDetailView: UIView {
var event: Event?
let model = EventsModel()
override init(frame: CGRect) {
super.init(frame: frame)
print("selected event: \(event)") <<<<--- Prints "nil"
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
// Second Controller
class EventDetailController: UIViewController {
var eventDetailView: EventDetailView!
override func loadView() {
super.loadView()
view = eventDetailView
}
override func viewDidLoad() {
super.viewDidLoad()
}
}

Answer 1

You are passing data which is not the correct way to do this. You should never access the view until it's been shown or loaded correctly.
In your class EventDetailController add the property
var event: Event?
and replace this method like below
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let vc = EventDetailController()
vc.event = model.events[indexPath.item]
navigationController?.pushViewController(vc, animated: true)
}
and
override func viewDidLoad() {
super.viewDidLoad()
eventDetailView.event = self.event
}
Hope it helps
EDIT
In load view method add the following line at the start of the method
`eventDetailView = EventDetailView(frame:CGRect(x:0,y:0,width:UIScreen.main.bounds.width,height:UIScreen.main.bounds.height))`

Answer 2

// First View Controller
let vc = EventDetailController()
vc.eventDetailView.event = "TEST"
navigationController?.pushViewController(vc, animated: true)
// Second View
class EventDetailView: UIView {
var event: String?
var model = EventsModel()
override init(frame: CGRect) {
super.init(frame: frame)
print("selected event: \(event)")
}
override func encode(with aCoder: NSCoder) {
super.encode(with: aCoder)
aCoder.encode(event as Any?, forKey: "event")
aCoder.encode(model as Any?, forKey: "model")
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
event = aDecoder.decodeObject(forKey: "event") as? String? ?? ""
model = aDecoder.decodeObject(forKey: "model") as! EventsModel? ?? EventsModel()
}
}
// Second Controller
class EventDetailController: UIViewController {
var eventDetailView = EventDetailView()
override func loadView() {
super.loadView()
view = eventDetailView
}
override func viewDidLoad() {
super.viewDidLoad()
print(eventDetailView.event)
}
}