Found nil when unwrapping optional value in core data - ios

Question

I've been trying to address this issue for a few days and it seems I'm only going in circles.
I'm adding data to core data by tapping on tableView cells and then displaying the items on another tableView.
That works great, the problem is this:
When I click on the other table view rows, to be able to see the item with all the other values stored in core data, I get
Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value on the showMeTheGoodiesTwo(entry: myCart) line
...Inside viewDidLoad. But I do not know why that's happening, as the entity is not empty.
Here's the code of the view controller where I want to display the item's details.
Hope somebody can give me a hand.
Cheers!
import UIKit
class productQuantityViewController: UIViewController {
var myCart: Cart!
#IBOutlet weak var productImage: UIImageView!
#IBOutlet weak var productNameLabel: UILabel!
#IBOutlet weak var productDescriptionLabel: UILabel!
#IBOutlet weak var productAmountLabel: UITextField!
#IBOutlet weak var minusButton: UIButton!
#IBOutlet weak var plusButton: UIButton!
override func viewDidLoad() {
super.viewDidLoad()
productImage.layer.cornerRadius = 10
minusButton.layer.cornerRadius = minusButton.frame.size.width/2
plusButton.layer.cornerRadius = plusButton.frame.size.width/2
showMeTheGoodiesTwo(entry: myCart)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func showMeTheGoodiesTwo(entry: Cart) {
let name = entry.product
let quantity = entry.inventory
let description = entry.productDescription
let image = entry.productImage as Data?
let xNSNumber = quantity as NSNumber
productNameLabel!.text = name
productDescriptionLabel!.text = description
productAmountLabel!.text = xNSNumber.stringValue
productImage!.image = UIImage(data:image!)
print(productNameLabel.text as Any)
}
}

Answer 1

You need to change
var myCart: Cart!
To
var myCart: Cart?
? is use to make it optional.
And in viewDidLoad use
if (myCart != nil){
showMeTheGoodiesTwo(entry: myCart)
} else {
//do something.
}
instead of
showMeTheGoodiesTwo(entry: myCart)