Independently auto fade UITableView rows starting with the bottom row - swift

Question

Examples of row deletion usually implement textFieldDidEndEditing or some other gesture / user input method.
My version of an auto-deletion feature is to use animateWithDuration with alpha. It's simple and looks good.
The challenge is I would like to do this automatically via NSTimer or animateWithDuration independently of any user scrolling and user input. Just a simple fade-out starting with the newest bottom row and have it stay alpha 0 as it moves up the table.
Currently you don't see any rows when you open the app because the rows have already faded out. This is good. The problem occurs every time a user sends a new posts all the "invisible" rows appear again starting at alpha 1 and then all fade out together.
I need the previous rows above to stay at alpha 0 with only the new bottom row having alpha 1 then it fades away to alpha 0.
Is it because I need to use cellForRowAtIndexPathinstead? Or do I need to use the dequeueReusableCellWithIdentifier method?
override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell = super.collectionView(collectionView, cellForItemAtIndexPath: indexPath) as! CHEFTALKRecipeViewCell
let recipe = recipes[indexPath.item]
if recipe.posterId == posterId {
cell.textView!.textColor = UIColor.blackColor()
// STEP 1
cell.contentView.alpha = 1
} else {
// do something
}
return cell
}
// STEP 2
override func collectionView(collectionView: UICollectionView, willDisplayCell cell: UICollectionViewCell, forItemAtIndexPath indexPath: NSIndexPath) {
UIView.animateWithDuration(2.0) {
cell.contentView.alpha = 0
}
}

Answer 1

As much as I understand your problem is that all cells animate. Even the ones at the top.
If so, you can retrieve -visibleCells from UICollectionView and start animation if only their position is at the bottom of the screen.