How to remove fade animation of UICollectionView during rotation time?

Question

I am just trying to adapt animation of CollectionView during rotation time , so that there wouldn't be any fade effects like this

Just simple move of the view. So after a small search i found out that I accomplish that effect by just overriding two methods of UICollectionViewFlowLayout

 override func initialLayoutAttributesForAppearingItem(at itemIndexPath: IndexPath) -> UICollectionViewLayoutAttributes? {

return nil

}
 override func finalLayoutAttributesForDisappearingItem(at itemIndexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
      return layoutAttributesForItem(at: itemIndexPath) 

}

But then another issue came into effect: when i receive message in between two messages like receiving messages with delay

Blue messages not just shift down, but old instance of a blue message is stays in place for short time and then goes down. But if I return to initial prefernces both

  override func initialLayoutAttributesForAppearingItem(at itemIndexPath: IndexPath) -> UICollectionViewLayoutAttributes? {

return nil

}
 override func finalLayoutAttributesForDisappearingItem(at itemIndexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
      return nil 

}

Messages moves appropriately in a neat way but fading effect during rotation again takes place.

This thing is very confused me, please maybe someone has any clue how can I keep rotation animation without fading effect and make messages animation effect like a plain messages movement.

Answer 1

I think I found the solution. 1) I need to find out the IndexPaths of elements being inserted in CollectionView. 2) Calculate next elements laying after IndexPath being inserted(when i receive message in between two messages like receiving messages with delay ) 3) applying new initialLayoutAttributesForAppearingItem and finalLayoutAttributesForDisappearingItem to my IndexPaths array derived above, for the rest elements we just applying that preferences

 override func initialLayoutAttributesForAppearingItem(at itemIndexPath: IndexPath) -> UICollectionViewLayoutAttributes? {

return nil

}
    override func finalLayoutAttributesForDisappearingItem(at itemIndexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
  return layoutAttributesForItem(at: itemIndexPath) 

 }

here is code

   override func prepare(forCollectionViewUpdates updateItems: [UICollectionViewUpdateItem]) {

    super.prepare(forCollectionViewUpdates: updateItems)
               insertingIndexPaths.removeAll()
    print("begining : \(insertingIndexPaths)")


    // create an array

    let fullAmountOfCells = collectionView?.numberOfItems(inSection: 0)
    print("number of items: \(fullAmountOfCells)")

    for update in updateItems {
        if let indexPath = update.indexPathAfterUpdate,
            update.updateAction == .insert {
            insertingIndexPaths.append(indexPath)
            print("Example if indexPath if for loop:\(indexPath)")
        }

   }
    let lastPathOfInsertingElement = insertingIndexPaths.last
    let differenceBetweenFullAmountAndLastInsertElement = fullAmountOfCells! - (lastPathOfInsertingElement?.item)! - 1

    if differenceBetweenFullAmountAndLastInsertElement > 0 {
        for numeric in 1...differenceBetweenFullAmountAndLastInsertElement {
            insertingIndexPaths.append(IndexPath(item: numeric + (lastPathOfInsertingElement?.item)!, section: 0))
        }
        print("True array to be modified with attributes:\(insertingIndexPaths)")

}
 }

override func finalizeCollectionViewUpdates() {
    super.finalizeCollectionViewUpdates()
  //  ChatLogController.orientation = UIDevice.current.orientation
//    print(  ChatLogController.orientation = UIDevice.current.orientation)
    insertingIndexPaths.removeAll()
    movingIndexPath.removeAll()
}



   override func initialLayoutAttributesForAppearingItem(at itemIndexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
    let attributes = super.initialLayoutAttributesForAppearingItem(at: itemIndexPath)

    if insertingIndexPaths.contains(itemIndexPath) {
        // attributes?.alpha = 0.0
        //attributes?.transform = CGAffineTransform(scaleX: 0.1, y: 0.1)

        print("Process in initialLayoutAttributesForAppearingItem: \(itemIndexPath)")
           return attributes

    } else {
         print("Process in initialLayout set to nil: \(itemIndexPath)")
        return nil
    }


}








  override func finalLayoutAttributesForDisappearingItem(at itemIndexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
let attributes = super.initialLayoutAttributesForAppearingItem(at: itemIndexPath)

if insertingIndexPaths.contains(itemIndexPath) {
    // attributes?.alpha = 0.0
    //attributes?.transform = CGAffineTransform(scaleX: 0.1, y: 0.1)


    return nil

} else {
    print("processing final layout and it to leyoutAttributeForItem(at: \(itemIndexPath)")
    return layoutAttributesForItem(at:itemIndexPath)
}



  }