Accessing collectionView cells visible/invisible - swift3

Question

I got a function to flip my collection view cells, which is working fine. My problem is that I want to flip all the cells and not just this one visible cell, so when I swipe to next cell it will be flipped.
This is what I am using to flip the one visible cell only. Any help in the right direction would be appreciated.
func flipAction() {
let visibleRect = CGRect(origin: mainCollecView.contentOffset, size: mainCollecView.bounds.size)
let visiblePoint = CGPoint(x: visibleRect.midX, y: visibleRect.midY)
let visibleIndexPath = mainCollecView.indexPathForItem(at: visiblePoint)
let cell = mainCollecView.cellForItem(at: visibleIndexPath!) as! MainCollectionViewCell
if cell.isFlipped == false {
//Flip card
cell.flip()
cell.isFlipped = true
flipBtn.setImage(UIImage(named: "reversed"), for: .normal)
} else {
// Flip the card back
flipBtn.setImage(UIImage(named: "Calendar"), for: .normal)
cell.flipBack()
cell.isFlipped = false
}
}

Answer 1

You can use different approaches. But if you want all to be flipped, use a variable in you Class, like
var isFlipped:Bool = false
Inside your function now:
flipAction() {
isfliped = !isfliped
mycollection.reload() //where mycollection is yours
}
Then inside your
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell
{
if isfliped == false {
// your code for cell when is not flipped
} else {
//your code for cell when is flipped
}
This way all cells will be flipped or not at once, not depending if they are visible or not.