It was working in the playground but not the app. As I thought I had used the code incorrectly :). With some work I got it to function in the app too. Here is how it looks now:         let button = UIButton()         button.addTarget(self, action: #selector(self.selectTack(sender:)), for: .touchUpInside)             let filteredProducts = products.filter { $0.item.contains(key)}             for product in filteredProducts {                 if let itemPosition = product.item.firstIndex(of: key) {                     let foundColor = product.colorName[itemPosition]                     if value > 0 {                     button.setTitle("\(foundColor) \(product.brand) \(product.category), amount: \(value)", for: UIControl.State.normal)                     tackStack.addArrangedSubview(button)                 }             }         }     }

Nice! It's working perfectly now :)

Ok, now the function is triggered, but how do you reload a collectionView? I think that will be the easiest way to do it

Ahh, I thought functionToUpdate didn't make sense. I have now made a function in herdViewController     func refreshHerd() {         print("refresh")     } and then updated viewWillDisappear but get an error: "Expression resolves to an unused function"     override func viewWillDisappear(_ animated: Bool) {         super.viewWillDisappear(animated)             if let vc1 = self.navigationController?.topViewController as? HerdViewController {                     vc1.refreshHerd                 }     } I know how to remove cells from a stack view and then replace them programmatically, but a collectionView is different, it seems to just "be there" regardless of what happens in the lifecycle of the VC besides these two, but it doesn't make any difference if I place them in viewDidLoad or viewWillAppear: herdCollectionView.delegate = self         herdCollectionView.dataSource = self

VC1 is HerdViewController and VC2 is HorseViewController. The Home Screen has a button for each navigation controller, HerdViewController starts the first navigation controller I get an error "Value of type 'HerdViewController' has no member 'functionToUpdate'"   override func viewWillDisappear(_ animated: Bool) {         super.viewWillDisappear(animated)             if let vc1 = self.navigationController?.topViewController as? HerdViewController {                     vc1.functionToUpdate                 }     }

If I go with the second method and write:     func viewWillDisappear() {         let vcs = vC2.navigationController?.viewControllers         let vc1 = vcs[0]             vc1.functionToUpdate     } Is "vc1" and "vc2" meant to match the class of the viewControllers in the project? Is this written correctly or are parts supposed to be in VC1? The navigation controller starts after the Home Screen, btw, I didn't mention that before. I have three navigation controllers branching off from the initial VC, is this bad practice or normal in IOS development?

I knew there was a problem with my for loop, thanks for clearing that up :D

VC     func addButtons() {         for (feed,amount) in feedInventory where amount 0 {             let filteredProducts = feedProducts.filter { $0.code.contains(feed)}             for feedProduct in filteredProducts {                 let horizontalStack = UIStackView(frame: .zero)                 horizontalStack.axis = .horizontal                 horizontalStack.alignment = .firstBaseline                 let label = UILabel(frame: .zero)                 label.text = "\(feedProduct.name)"                 horizontalStack.addArrangedSubview(label)                 let rationAmount = UILabel(frame: .zero)                 let rationIndex = Int(rationArrayPosition[feedProduct.code]!)                 rationAmount.text = "\(myHorses[horseIndex].ration[rationIndex])"                 horizontalStack.addArrangedSubview(rationAmount)                 let stepper = UIStepper(frame: .zero)                 stepper.minimumValue = 0                 stepper.maximumValue = 900                 stepper.wraps = false                 stepper.autorepeat = false                 stepper.addTarget(self, action: #selector(stepperValueChanged(_:)), for: .valueChanged)                 stepper.accessibilityLabel = "\(feedProduct.code)"                 horizontalStack.addArrangedSubview(stepper)                 feedStack.addArrangedSubview(horizontalStack)                 }}}     func removeButtons() {         let rows = feedStack.arrangedSubviews             .filter {$0 is UIStackView}         for row in rows {             feedStack.removeArrangedSubview(row)                 row.removeFromSuperview()             }         }     @objc func stepperValueChanged(_ sender:UIStepper!) {         let rationIndex = rationArrayPosition[sender.accessibilityLabel!]         myHorses[horseIndex].ration[rationIndex ?? 00] += Int(sender.value)         print(myHorses[horseIndex].ration[rationIndex ?? 00])         removeButtons()         addButtons()       } Model var feedInventory: [ String : Int ] = [     "oats" : 0,     "soyPellets" : 20 ] var feedProducts = [     FeedProduct(name: "Oats", code: "oats"),     FeedProduct(name: "Soy Pellets", code: "soyPellets") ] var rationArrayPosition: [ String : Int ] = [     "oats" : 0,     "soyPellets" : 1 ] struct Horse {     var name : String! var ration : [Int] } var horseIndex = 0 var myHorses = [     Horse(name: "Donnerhall", ration: [2,0]),     Horse(name: "Celeste", ration: [3,1]) ]

Forgot that one:    @IBOutlet weak var feedStack: UIStackView!     and feedProduct is defined here in the for loop: for feedProduct in filteredProducts {

It's tricky on this forum as I can't edit a post or comments, but I'll post it again with edits: VC     func addButtons() {         for (feed,amount) in feedInventory where amount 0 {             let filteredFeedProducts = feedProducts.filter { $0.code.contains(feed)}             for filteredFeed in filteredFeedProducts {                 let horizontalStack = UIStackView(frame: .zero)                 horizontalStack.axis = .horizontal                 horizontalStack.alignment = .firstBaseline                              let label = UILabel(frame: .zero)                 label.text = "\(filteredFeed.name)"                 horizontalStack.addArrangedSubview(label)                                let rationAmount = UILabel(frame: .zero)                 let rationIndex = Int(rationArrayPosition[filteredFeed.code]!)                 rationAmount.text = "\(myHorses[horseIndex].ration[rationIndex])"                 horizontalStack.addArrangedSubview(rationAmount)                                  let stepper = UIStepper(frame: .zero)                 stepper.minimumValue = 0                 stepper.maximumValue = 900                 stepper.wraps = false                 stepper.autorepeat = false                 stepper.addTarget(self, action: #selector(stepperValueChanged(_:)), for: .valueChanged)                 stepper.accessibilityLabel = "\(filteredFeed.code)"                 horizontalStack.addArrangedSubview(stepper)                  feedStack.addArrangedSubview(horizontalStack)                 }}}     func removeButtons() {         let rows = feedStack.arrangedSubviews             .filter {$0 is UIStackView}         for row in rows {             feedStack.removeArrangedSubview(row)                 row.removeFromSuperview()             }         }          @objc func stepperValueChanged(_ sender:UIStepper!) {         let rationIndex = rationArrayPosition[sender.accessibilityLabel!]         myHorses[horseIndex].ration[rationIndex ?? 00] += Int(sender.value)         print(myHorses[horseIndex].ration[rationIndex ?? 00])       removeButtons()         addButtons()       } Model var feedInventory: [ String : Int ] = [    "oats" : 0,    "soyPellets" : 20] var feedProducts = [    FeedProduct(name: "Oats", code: "oats"),    FeedProduct(name: "Soy Pellets", code: "soyPellets")] var rationArrayPosition: [ String : Int ] = [    "oats" : 0,    "soyPellets" : 1] struct Horse {    var name : String! var ration : [Int] } var horseIndex = 0 var myHorses = [    Horse(name: "Donnerhall", ration: [2,0]),    Horse(name: "Celeste", ration: [3,1])] @IBOutlet weak var feedStack: UIStackView! struct FeedProduct {   var name : String   var code : String }

I guess you cannot use = Int(sender.value) because you are not setting the value property of the stepper. I tried setting a value, but 1 is default so this seemed unnecessary. either way, when pressing the button it resets the whole thing to 0 so I only ever get to 1. If I use += Int(sender.value) it works, but will only ever increase. I need to be able to decrease as well @objc func stepperValueChanged(_ sender: UIStepper) { rationAmount.text = "\(Int(sender.value))" //- Update the text property of the right UILabel onValueChanged?(self) } My aim with the VC is to change the value of the ration array in the model, the VC only shows the number listed in the model

Aha, I understand now. Sorry for jumping to conclusions. I didn't know it could be done that way :). This might help me move some code from the Vc to the model in other parts of my app :)

struct FeedProduct {     var name : String     var code : String }

I'm not sure to be honest, this code was suggested in another post and I altered it, but there was never a frame defined in the first stackView. The layout works without it for now. Does this affect how the stepper alters values in the model?

Thanks! That works nicely