SwiftUI - Memory Management - memory-management

Question

OK, so I'm looking to improve memory within my app.
I have enabled Live Memory Allocation for my project and I'm using the Debug Graph Tool. I'm looking at the backtraces, and coming across issues, which in total honesty, does not make sense to me. I've, to the best of my knowledge, removed strong references, but I am getting issues with parts of my code where I just don't understand/see the issue. And example of this is:
struct ProductScrollView: UIViewRepresentable {
private let view = UIScrollView()
func makeCoordinator() -> Coordinator {
return ProductScrollView.Coordinator(parent1: self)
}
#State var currentPage: Int
#Binding var products: [ProductModel]
func makeUIView(context: Context) -> UIScrollView {
if view.superview == .none {
let childView = UIHostingController(rootView: ProductCell(products: $products, currentPage: currentPage, pageCount: products.count)
) <---- Debugger seems to indicate this with the message "Thread 1"
childView.view.frame = CGRect(x: 0, y: 0, width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height * CGFloat((products.count)))
view.contentSize = CGSize(width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height * CGFloat((products.count)))
view.addSubview(childView.view)
view.showsVerticalScrollIndicator = false
view.showsHorizontalScrollIndicator = false
view.contentInsetAdjustmentBehavior = .never
view.isPagingEnabled = true
view.delegate = context.coordinator
}
return view
}
func updateUIView(_ uiView: UIScrollView, context: Context) {
uiView.contentSize = CGSize(width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height * CGFloat((products.count)))
for i in 0..<uiView.subviews.count {
uiView.subviews[i].frame = CGRect(x: 0, y: 0, width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height * CGFloat((products.count)))
}
}
class Coordinator: NSObject, UIScrollViewDelegate {
var parent: ProductScrollView
init(parent1: ProductScrollView){
parent = parent1
}
func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
let index = Int(scrollView.contentOffset.y / UIScreen.main.bounds.height)
parent.currentPage = index
}
deinit {
print("Coordiante scroll view desroted")
}
}
}
Which doesn't make complete sense to me, however, I believe the line:
return ProductScrollView.Coordinator(parent1: self)
May be the issue?
I'll even have the debugger point to functions that are performed on my onAppear method.
Could someone please help as to what I can do to better understand these issues and eliminate them?
Edit -
To delve even further, this line appears in my backtrace:
static var FEEDBACK = FeedbackAPI()
Is it due to creating a new instance everytime?

Answer 1

By design we need to instantiate view inside makeView, so SwiftUI manages UIView lift-cycle to be the same as representable view, like
struct ProductScrollView: UIViewRepresentable {
func makeCoordinator() -> Coordinator {
return ProductScrollView.Coordinator(parent1: self)
}
#State var currentPage: Int
#Binding var products: [ProductModel]
func makeUIView(context: Context) -> UIScrollView {
let view = UIScrollView() // << here !!
// ... other code
}