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iOS Build a Vending Machine App in Swift Using the Vending Machine Updating the Price

Posted by HsinTing Hsieh
HsinTing Hsieh
4,115 Points

get error of optional type VendingSelection?

here is part of my code, and error shows: Value of optional type 'VendingSelection?' not unwrapped; did you mean to use '!' or '?'?

// MARK: - UICollectionViewDelegate

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    updateCell(having: indexPath, selected: true)

    currentSelection = vendingMachine.selection[indexPath.row]

    if let currntselection = currentSelection, let item = vendingMachine.irem(forSelection: currentSelection) {

        priceLabel.text = "$\(item.price)"
        totalLabel.text = "$\(item.price * Double(quantity))"
    }
}
HsinTing Hsieh
HsinTing Hsieh
4,115 Points

my code looks like the same as tutor's. I don't know where I did wrong..

1 Answer

Ignazio Calo
PLUS
Ignazio Calo
Courses Plus Student 1,819 Points
Ignazio Calo
Ignazio Calo
Courses Plus Student 1,819 Points

look at your line:

if let currntselection = currentSelection, let item = vendingMachine.irem(forSelection: currentSelection) { }

which object are you using inside the vendingMachine.irem(forSelection: currentSelection) ?

There is a typo on the first variable definition, therefore you're still using the global optional currentSelection object.

I really suggest to use different names inside the if let <something> = <something>.

Gavin Hobbs
Gavin Hobbs
5,205 Points
Gavin Hobbs
Gavin Hobbs
5,205 Points

Hey Ignazio Calo we would use different names for if let <something> = <something>; however, those are the names Pasan used. I totally understand your reasoning though.