Highlighting a UICollectionViewCell while it's not been into the view window.

UICollectionView+Highlight.h

//
//  UICollectionView+Highlight.h
//
//  Created by Ratul Sharker on 9/18/17.
//

#import <UIKit/UIKit.h>

@interface UICollectionView (Highlight)

/*
 *  This method must be installed inside the
 *  cellForItemAtIndexPath. Before returning
 *  the cell to the UIKit, you must call this
 *  this method so all case of highlighting
 *  is covered.
 */
-(void)pendingHighlightCell:(UICollectionViewCell*)cell
              withIndexPath:(NSIndexPath*)indexPath;

/*
 *  call this method to highlight a particular cell
 *  with a particular background color.
 */
-(void)highlightCollectionViewCellAtIndexPath:(NSIndexPath*)indexPath
                                    withColor:(UIColor*)highColor;

@end

UICollectionView+Highlight.m

//
//  UICollectionView+Highlight.m
//
//  Created by Ratul Sharker on 9/18/17.
//

#import "UICollectionView+Highlight.h"

@implementation UICollectionView (Highlight)

-(void)pendingHighlightCell:(UICollectionViewCell*)cell
              withIndexPath:(NSIndexPath*)indexPath
{
    if(shouldHighlightInCellForItemAtIndexPath &&
       indexPath.row == highlightingIndexPath.row &&
       indexPath.section == highlightingIndexPath.section)
    {
        // cell is already present in the scene
        shouldHighlightInCellForItemAtIndexPath = NO;
        
        UIColor *originalColor = cell.backgroundColor;
        cell.backgroundColor = highlightingColor;
        [UIView animateWithDuration:2.0
                         animations:^{
                             cell.backgroundColor = originalColor;
                         }];
    }
}


BOOL shouldHighlightInCellForItemAtIndexPath = NO;
static NSIndexPath      *highlightingIndexPath;
static UIColor          *highlightingColor;

-(void)highlightCollectionViewCellAtIndexPath:(NSIndexPath*)indexPath
                                    withColor:(UIColor*)highColor
{
    UICollectionViewCell *cell = [self cellForItemAtIndexPath:indexPath];
    
    if(cell)
    {
        // cell is already present in the scene
        shouldHighlightInCellForItemAtIndexPath = NO;
        
        UIColor *originalColor = cell.backgroundColor;
        cell.backgroundColor = highColor;
        [UIView animateWithDuration:2.0
                         animations:^{
                             cell.backgroundColor = originalColor;
                         }];
        
    }
    else
    {
        // cell is not present in the scene
        
        // store the position
        highlightingIndexPath = indexPath;
        highlightingColor = highColor;
        shouldHighlightInCellForItemAtIndexPath = YES;
    }
}

@end