Using Custom Layout Causes collectionViewFlowLayout delegate function not being called

问题

I am using TRMosaicLayout to achieve a SnapChat like layout.

However, after using it, I noticed that viewForSupplementaryElementOfKind is no longer called. Any thoughts?

func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {

    print("THIS FUNCTION IS NO LONGER CALLED");
    var view: UICollectionReusableView! = UICollectionReusableView();
    switch kind {
    case UICollectionElementKindSectionFooter:

        loadingFooterView = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "loadingFooterIdentifier", for: indexPath) as! LoadingFooterCollectionReusableView;

        view = loadingFooterView;

    default:
        break;
    }

    return view;
}

来源：https://stackoverflow.com/questions/43221323/using-custom-layout-causes-collectionviewflowlayout-delegate-function-not-being