swift collection view deselects item when scroll off screen
class MyViewController {
var selectedIndexes = [IndexPath]()
func cellForItem(indexPath) {
cell.isSelected = selectedIndexes.contains(indexPath)
}
func didSelectCell(indexPath) {
if selectedIndexes.contains(indexPath) {
selectedIndexes.remove(indexPath)
} else if selectedIndexes.count < limiit {
selectedIndexes.append(indexPath)
}
}
}