UICollectionView header dynamic height using Auto Layout

Question

I have a UICollectionView with a header of type UICollectionReusableView.

In it, I have a label whose length varies by user input.

Answer 1

Swift 3

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize{
    return CGSize(width: self.myCollectionView.bounds.width, height: self.mylabel.bounds.height)
}

https://developer.apple.com/reference/uikit/uicollectionviewdelegateflowlayout/1617702-collectionview