PickerCollectionViewFlowLayout use for custom paging in your existing code, used for multiple cell in your collection view with custom paging. //don't forget to disable the paging.

PickerCollectionViewFlowLayout.swift

//
//  PickerCollectionViewFlowLayout.swift
//
//  Created by Sachin Nautiyal on 21/06/17.
//  Copyright © 2017 Sachin Nautiyal. All rights reserved.
//

import UIKit

class PickerCollectionViewFlowLayout: UICollectionViewFlowLayout {

    override func awakeFromNib() {
        super.awakeFromNib()
        
        self.itemSize = CGSize(width: 50.0, height: 50.0) //if you want to define the cell size here.
        self.scrollDirection = .horizontal // set your scrolling direction here. Right now its only for horizontal.
    }

    override func targetContentOffset(forProposedContentOffset proposedContentOffset: CGPoint, withScrollingVelocity velocity: CGPoint) -> CGPoint {
        
        if let collectionView = collectionView,
            let first = layoutAttributesForItem(at: IndexPath(row: 0, section: 0)),
            let last = layoutAttributesForItem(at: IndexPath(row: collectionView.numberOfItems(inSection: 0) - 1, section: 0))
        {
            sectionInset = UIEdgeInsets(top: 0, left: collectionView.frame.width / 2 - first.bounds.size.width / 2, bottom: 0, right: collectionView.frame.width / 2  - last.bounds.size.width / 2)
        }
        
        let collectionViewSize = self.collectionView!.bounds.size
        let proposedContentOffsetCenterX = proposedContentOffset.x + collectionViewSize.width * 0.5
        
        var proposedRect = self.collectionView!.bounds
        
        // comment this out if you don't want it to scroll so quickly
        proposedRect = CGRect(x: proposedContentOffset.x, y: 0, width: collectionViewSize.width, height: collectionViewSize.height)
        
        var candidateAttributes: UICollectionViewLayoutAttributes?
        for attributes in self.layoutAttributesForElements(in: proposedRect)! {
            // == Skip comparison with non-cell items (headers and footers) == //
            if attributes.representedElementCategory != .cell {
                continue
            }
            
            
            // Get collectionView current scroll position
            let currentOffset = self.collectionView!.contentOffset
            
            // Don't even bother with items on opposite direction
            // You'll get at least one, or else the fallback got your back
            if (attributes.center.x <= (currentOffset.x + collectionViewSize.width * 0.5) && velocity.x > 0) || (attributes.center.x >= (currentOffset.x + collectionViewSize.width * 0.5) && velocity.x < 0) {
                continue
            }
            
            
            // First good item in the loop
            if candidateAttributes == nil {
                candidateAttributes = attributes
                continue
            }
            
            // Save constants to improve readability
            let lastCenterOffset = candidateAttributes!.center.x - proposedContentOffsetCenterX
            let centerOffset = attributes.center.x - proposedContentOffsetCenterX
            
            if fabsf( Float(centerOffset) ) < fabsf( Float(lastCenterOffset) ) {
                candidateAttributes = attributes
            }
        }
        
        if candidateAttributes != nil {
            // Great, we have a candidate
            return CGPoint(x: candidateAttributes!.center.x - collectionViewSize.width * 0.5, y: proposedContentOffset.y)
        } else {
            // Fallback
            return super.targetContentOffset(forProposedContentOffset: proposedContentOffset)
        }
    }
}