Get CollectionView cells that are invisible

Question

Intro

I know that this topic has been discussed a lot on StackOverflow and am aware that a Collection View recycles its cells .

However, I have not found a suitable explanation for the problem I describe below.

Problem

In my app, I have a collection view that has multiple cell types in it - each cell only exists once in the collection view.

The collection view acts like a form in which the user can enter different things - split up on a few cells.

If I now scroll down, the first cell is not visible anymore. However, it is also not removed from the collection view as the entered data is still correctly displayed if I scroll back to the top.

If a user clicks a button, I am fetching every collection view cell from the collection view and run a validation method on it.

Just like the following:

let firstCell = myCollectionView.cellForItem(at: IndexPath(row: 0, section: 0)) as! DefaultElementCell // get the cell

firstCell.validateEntries() // validates entries and highlights incorrect fields

If I now scroll to the bottom of the collection view (the last cell), I get an error "unexpectedly found nil while unwrapping an optional value" . The optional value in this case is the Cell that should be returned by cellForItemAt() .

So, I think that the cell has already been removed but on the other hand the text entered into the fields and everything are still there if I scroll back to the first cell.

What I tried:

if let firstCell = myCollectionView.dataSource?.collectionView(self.myCollectionView, cellForItemAt: IndexPath(row: 0, section: 0)) {
            print((firstCell as! DefaultElementCell).validateEntries()) // does nothing
}

Now, I don't get the error "unexpectedly found nil" anymore but validateEntries() also does nothing anymore.

Is there any way I can correctly get the invisible collection view cells or prevent the collection view from re-using cells? As already mentioned, every cell type only exists once in the collection view.

I would appreciate any help!

Answer 1

You need to create an array of same size as you number of cells then

var arr = [String]() 

 // inside cellForRowAt 
cell.textfield.addTarget(self, action: #selector(self.textFieldDidChange(_:)), for: UIControl.Event.editingChanged
cell.textfield.tag = indexPath.item

and

@objc func textFieldDidChange(_ textField: UITextField) {
   arr[textfiled.tag] = textfield.text!
}

then validate you entry from arr values