             "collectionView":collectionView,
             "spinner":spinner]
         
-        let metrics:[String:CGFloat] = [:]
+        let metrics:[String:CGFloat] = [
+            "headerHeight":kHeaderHeight]
         
         addConstraints(NSLayoutConstraint.constraints(
             withVisualFormat:"H:|-0-[collectionView]-0-|",

        { [weak self] in
            
            self?.spinner.stopAnimating()
            self?.collectionView.isHidden = false
        }
    }
    

            metrics:metrics,
            views:views))
        addConstraints(NSLayoutConstraint.constraints(
            withVisualFormat:"V:|-0-[spinner(headerHeight)]",
            options:[],
            metrics:metrics,
            views:views))
