Error: UICollectionView received layout attributes for a cell with an index path that does not exist in Swift

Question

I "https://www.raywenderlich.com/392-uicollectionview-custom-layout-tutorial-pinterest" To create a Custom UICollectionView. (To adjust cell height)

If I scroll up, the cell will continue to be added, and scroll from top to bottom to refresh.

There is no problem when you run your app and initially grow Cells. However, there is always an error when refreshing or reordering the number of cells.

ERROR :

*** Assertion failure in -[UICollectionViewData validateLayoutInRect:], /BuildRoot/Library/Caches/com.apple.xbs/Sources/UIKitCore/UIKit-3698.93.8/UICollectionViewData.m:447

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'UICollectionView received layout attributes for a cell with an index path that does not exist :

Therefore, "iOS 10 bug: UICollectionView received layout attributes for a cell with an index path that does not exist" And tried to solve the error.

on the line below

self.artCollectionView.reloadData () 

I tried adding

self.artCollectionView.collectionViewLayout.invalidateLayout () 

but it was not resolved.

Also, I do not know where to run

cache.removeAll ()

in the prepare () section. (There is a prepare () function in PinterestLayout.swift)

What is the correct way to resolve the error?

Answer 1

There is prepare function in PinterestLayout.swift as it should be because it is the only layout used for customizing the collectionView.

At line 76, in PinterestLayout.swift file.

Try

override public func prepare() {
    cache.removeAll()
    if cache.isEmpty {
       .....
    }
}

Answer 2

extension UICollectionView{
   func refreshLayout() {
        let oldLayout = collectionViewLayout as! UICollectionViewFlowLayout
        let newLayout = UICollectionViewFlowLayout()
        newLayout.estimatedItemSize = oldLayout.estimatedItemSize
        newLayout.footerReferenceSize = oldLayout.footerReferenceSize
        newLayout.headerReferenceSize = oldLayout.headerReferenceSize
        newLayout.itemSize = oldLayout.itemSize
        newLayout.minimumInteritemSpacing = oldLayout.minimumInteritemSpacing
        newLayout.minimumLineSpacing = oldLayout.minimumLineSpacing
        newLayout.scrollDirection = oldLayout.scrollDirection
        newLayout.sectionFootersPinToVisibleBounds = oldLayout.sectionFootersPinToVisibleBounds
        newLayout.sectionHeadersPinToVisibleBounds = oldLayout.sectionHeadersPinToVisibleBounds
        newLayout.sectionInset = oldLayout.sectionInset
        newLayout.sectionInsetReference = oldLayout.sectionInsetReference
        collectionViewLayout = newLayout
    }
  }

Then call:

YourCollectionView.refreshLayout()
YourCollectionView.reloadData()

Happy Coding!