Register nib with collectionview

Question

I have FeedCell.swift and FeedCell.xib, in feedcell xib i set cell custom class to 'FeedCell'

Code in view controller viewDidLoad

collectionView.register(UINib(nibName: "FeedCell", bundle: .main), forCellWithReuseIdentifier: "feedCell")

Problem:

I want to subclass FeedCell and use that class with collectionView Like:

class FeedCell:UICollectionViewCell {
    @IBOutlet weak var showImageView: UIImageView!
    @IBOutlet weak var showIconImageView: UIImageView!

}

class AppFeedCell: FeedCell { 
    override func awakeFromNib() {
       super.awakeFromNib()
       // configure cell
    }
}

How to register/use FeedCell and AppFeedCell with collectionview?

Answer 1

If your AppFeedCell have a different UI Configuration, for example it does not bind some IBOutlets defined in FeedCell or it adds new ones not present in it's superclass, then you will have to register both Nibs (asuming you have two separated Nib files)

collectionView.register(UINib(nibName: "FeedCell", bundle: .main), forCellWithReuseIdentifier: "feedCell")
collectionView.register(UINib(nibName: "AppFeedCell", bundle: .main), forCellWithReuseIdentifier: "appFeedCell")

And then you will be able to dequeue each one when you need.

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath:  NSIndexPath) -> UICollectionViewCell {
    if you_need_AppFeedCell {
        let cell : AppFeedCell = collectionView.dequeueReusableCellWithReuseIdentifier("appFeedCell", forIndexPath: indexPath) as! AppFeedCell
        return cell
    } else
        let cell : FeedCell = collectionView.dequeueReusableCellWithReuseIdentifier("feedCell", forIndexPath: indexPath) as! FeedCell
        return cell
    }
}

This way you may have two different Nib files even if AppFeedCell subclass FeedCell.

Otherwise, if both class and subclass share the same cell layout and outlets, then simply by casting the dequeued cell (FeedCell) to AppFeedCell should be enough, without registering another Nib, as Taras Chernyshenko pointed above.

Answer 2

You don't need to register separate xib for AppFeedCell. You already registered nib to your collectionView.

Just dequeue cell and cast it to needed class in your cellForItemAtIndexPath.

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath 
    indexPath:  NSIndexPath) -> UICollectionViewCell {
if you_need_AppFeedCell {
    let cell : AppFeedCell = collectionView.dequeueReusableCellWithReuseIdentifier("feedCell", forIndexPath: indexPath) as! AppFeedCell
    return cell
} else
    let cell : FeedCell = collectionView.dequeueReusableCellWithReuseIdentifier("feedCell", forIndexPath: indexPath) as! FeedCell
    return cell
}
}

Your AppFeedCell will inherit all outlets from FeedCell so it should work as well.