当scrollview快速滚动时，如何滚动collectionView？

Question

I have Scrollview and Collectionview, both of them scrolls horizontally

scrollview have pages and I want when scrollview scrolls, also scroll collectionview and select same indexed collectionview cell as scrollview page index

the problem here is that after scrollview scrolls, also scrolls collectionview and it selects cell same indexed as scrollview pages, but after that collectionview doesn't scrolls itself.

Sorry maybe bad format of question, I am new here

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell=collectionView.dequeueReusableCell(withReuseIdentifier: "mycell", for: indexPath) as! MenuListCollectionViewCell
    cell.commoninit(name: ListOfMenu[indexPath.row])

   let IndexForCol = (scrollview.contentOffset.x / scrollview.frame.size.width).rounded()

    if selectedIndex == Int(indexPath.row)
    {

        cell.backgroundColor = UIColor(hue: 0.6167, saturation: 1, brightness: 0.97, alpha: 1.0)
        cell.layer.cornerRadius = 14

    }
    if indexPath.row == Int(IndexForCol) {
        cell.backgroundColor = UIColor(hue: 0.6167, saturation: 1, brightness: 0.97, alpha: 1.0)

    }
    else
    {
        cell.backgroundColor = UIColor.clear
    }

    return cell
}



func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {   
 selectedIndex = indexPath.row
    UIView.animate(withDuration: 0.5, animations: {
        self.scrollview.contentOffset.x = self.scrollview.frame.width*CGFloat(indexPath.row)
    })

}




func scrollViewDidScroll(_ scrollView: UIScrollView) {
  let indexOfPage = round(scrollview.contentOffset.x / scrollview.frame.size.width)
  UIView.animate(withDuration: 0.5, animations: {
       self.collectionview.scrollToItem(at:IndexPath(item: Int(indexOfPage), section: 0), at: .right, animated: false)
  })
 collectionview.reloadData()

}

Simulator image:

Answer 1

scrollViewDidScroll is called for both the collectionView and the scrollView so give a tag to the scrollView then

//

func scrollViewDidScroll(_ scrollView: UIScrollView) {

  if scrollView.tag == 2 { // scrollView scrolled 
      use collectionView's scrollToItem
  }
  else {                    // collectionView scrolled 
       set contentOffset to the scrollView
  }

}