Stick header scroll down with other like header in tableview. #34

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1. qhu91it commented on Aug 6, 2018

   

   qhu91it

   on Aug 6, 2018

   Author

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   Finally, I got this solution to work.
   define the value

   let originY: CGFloat = 0
   let floatingSectionOriginY = collectionView.contentOffset.y

   If scrolling up use value from contentOffset.y to keep row is floating.

   var selectedOriginY = originY
   if floatingSectionOriginY >= originY {
       selectedOriginY = floatingSectionOriginY
   }

   Full code

   override func prepare() {
           guard delegate != nil,
               let collectionView = collectionView,
               collectionView.numberOfSections > 0
               else { return }
           
           if itemAttributes.count != collectionView.numberOfSections {
               generateItemAttributes(collectionView: collectionView)
               return
           }
           
           let originY: CGFloat = 0
           let floatingSectionOriginY = collectionView.contentOffset.y
           let originX: CGFloat = 0
           let floatingSectionOriginX = collectionView.contentOffset.x
           
           for section in 0..<collectionView.numberOfSections {
               for item in 0..<collectionView.numberOfItems(inSection: section) {
                   if section >= delegate.numberOfFirstRowFloat() 
                      && item >= delegate.numberOfFirstColumnFloat() {
                       continue
                   }
                   
                   let attributes = layoutAttributesForItem(at: IndexPath(item: item, section: section))!
                   
                   if section < delegate.numberOfFirstRowFloat() {
                       var selectedOriginY = originY
                       if floatingSectionOriginY >= originY {
                           selectedOriginY = floatingSectionOriginY
                       }
                       var frame = attributes.frame
                       let size = itemsSize[item]
                       frame.origin.y = selectedOriginY + (size.height * CGFloat(section))
                       attributes.frame = frame
                   }
                   
                   if item < delegate.numberOfFirstColumnFloat() {
                       var selectedOriginX = originX
                       if floatingSectionOriginX >= originX {
                           selectedOriginX = floatingSectionOriginX
                       }
                       var frame = attributes.frame
                       let prevItem = item - 1
                       if prevItem < 0 {
                           frame.origin.x = selectedOriginX
                       } else {
                           let size = itemsSize[prevItem]
                           frame.origin.x = selectedOriginX + (size.width * CGFloat(item))
                       }
                       attributes.frame = frame
                   }
               }
           }
       }