Swift - access instance of UIView from another function - ios

Question

In my project the user can create a UIView ("CustomWishlistView") like this:
func createCustomWishlistView() -> CustomWishlistView {
let v = CustomWishlistView()
v.translatesAutoresizingMaskIntoConstraints = false
v.backgroundColor = .darkGray
v.layer.cornerRadius = 30
return v
}
#IBAction func createListButtonTapped(_ sender: Any) {
// "Liste erstellen" button was tapped
self.appDidEnterBackgroundHandler()
if let txt = listNameTextfield.text {
self.newListTextfield.resignFirstResponder()
// append user-entered text to the data array
self.theData.append(txt)
self.imageData.append(self.image!)
let theCustomWishlistView = createCustomWishlistView()
self.view.addSubview(theCustomWishlistView)
// constrain CustomWishlistView
theCustomWishlistView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 120.0).isActive = true
theCustomWishlistView.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 0).isActive = true
theCustomWishlistView.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor, constant: 30.0).isActive = true
theCustomWishlistView.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor, constant: -30.0).isActive = true
theCustomWishlistView.wishlistImage.image = self.image
theCustomWishlistView.wishlistLabel.text = txt
theCustomWishlistView.transform = CGAffineTransform(translationX: 0, y: 1000)
self.view.bringSubviewToFront(containerView)
// reload the collection view
theCollectionView.reloadData()
theCollectionView.performBatchUpdates(nil, completion: {
(result) in
// scroll to make newly added row visible (if needed)
let i = self.theCollectionView.numberOfItems(inSection: 0) - 1
let idx = IndexPath(item: i, section: 0)
self.theCollectionView.scrollToItem(at: idx, at: .bottom, animated: true)
// close (hide) the "New List" view
self.closeButtonTappedNewList(nil)
})
}
}
I transform that view so it is not visible at first. It should appear after the user clicks on a cell inside a UICollectionView. My code for this (inside cellForItemAt) looks like this:
if indexPath.item <= theData.count {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "ContentCell", for: indexPath) as! ContentCell
cell.testLabel.text = theData[indexPath.item - 1]
cell.buttonView.setImage(imageData[indexPath.item - 1], for: .normal)
cell.customWishlistTapCallback = {
// let CustomWishlistView appear
// UIView.animate(withDuration: 0.3, delay: 0, options: .curveEaseIn, animations: {
// theCustomWishlistView.transform = CGAffineTransform(translationX: 0, y: 0)
// })
// let welcomeText disappear
UIView.animate(withDuration: 0.2, delay: 0, options: .curveEaseOut, animations: {
self.welcomeTextLabel.transform = CGAffineTransform(translationX: 0, y: 0)
})
}
return cell
}
My problem is that I can not let my customWishlistView appear because I can not access it. Is there a way to fix this problem? :)

Answer 1

You need to make theCustomWishlistView an instance variable like below. You don't show the entire class code, so my solution is as complete as I can make it without seeing the rest of your code
class CustomViewController: UIViewController, UICollectionViewDataSource {
var theCustomWishlistView: UIView?
func createCustomWishlistView() -> CustomWishlistView {
let v = CustomWishlistView()
v.translatesAutoresizingMaskIntoConstraints = false
v.backgroundColor = .darkGray
v.layer.cornerRadius = 30
return v
}
#IBAction func createListButtonTapped(_ sender: Any) {
// "Liste erstellen" button was tapped
self.appDidEnterBackgroundHandler()
if let txt = listNameTextfield.text {
self.newListTextfield.resignFirstResponder()
// append user-entered text to the data array
self.theData.append(txt)
self.imageData.append(self.image!)
let wishlistView = createCustomWishlistView()
self.view.addSubview(wishlistView)
// constrain wishlistView
wishlistView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 120.0).isActive = true
wishlistView.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 0).isActive = true
wishlistView.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor, constant: 30.0).isActive = true
wishlistView.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor, constant: -30.0).isActive = true
wishlistView.wishlistImage.image = self.image
wishlistView.wishlistLabel.text = txt
wishlistView.transform = CGAffineTransform(translationX: 0, y: 1000)
// retain wishlist view in instance variable
self.theCustomWishlistView = wishlistView
self.view.bringSubviewToFront(containerView)
// reload the collection view
theCollectionView.reloadData()
theCollectionView.performBatchUpdates(nil, completion: {
(result) in
// scroll to make newly added row visible (if needed)
guard let i = self.theCollectionView.numberOfItems(inSection: 0) else { return }
let idx = IndexPath(item: i - 1, section: 0)
self.theCollectionView.scrollToItem(at: idx, at: .bottom, animated: true)
// close (hide) the "New List" view
self.closeButtonTappedNewList(nil)
})
}
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return theData.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let _cell = collectionView.dequeueReusableCell(withReuseIdentifier: "ContentCell", for: indexPath)
guard let cell = _cell as? ContentCell else { return _cell }
cell.testLabel.text = theData[indexPath.item - 1]
cell.buttonView.setImage(imageData[indexPath.item - 1], for: .normal)
cell.customWishlistTapCallback = {
// let CustomWishlistView appear
UIView.animate(withDuration: 0.3, delay: 0, options: .curveEaseIn, animations: {
self.theCustomWishlistView?.transform = CGAffineTransform(translationX: 0, y: 0)
})
// let welcomeText disappear
UIView.animate(withDuration: 0.2, delay: 0, options: .curveEaseOut, animations: {
self.welcomeTextLabel.transform = CGAffineTransform(translationX: 0, y: 0)
})
}
return cell
}
}