which is scrolling and stopping comfortably like Snapchat and Instagram

SnapLikeCollectionView

The collectionView library which is scaling, scrolling and stopping comfortably like Snapchat and Instagram.

Demo1

Comparison with Instagram and Snapchat.

? This ?	Instagram	Snapchat

Demo2

You can change cell height since ver. 1.1.0

Requirements

Swift 4.2. Ready for use on iOS 11.0+

Installation

via Cocoapods

pod 'SnapLikeCollectionView'

Usage

Cell

You should use SnapLikeCell protocol.

Item is associatedtype. You can apply any model you want.

This Item becomes dataSource's items.

public protocol SnapLikeCell: class {
    associatedtype Item
    var item: Item? { get set }
}

Below is example.

import UIKit
import SnapLikeCollectionView

class SampleCell: UICollectionViewCell, SnapLikeCell {
    @IBOutlet weak var titleLabel: UILabel!
    
    var item: String? {
        didSet {
            titleLabel.text = item
        }
    }
}

ViewController

import UIKit
import SnapLikeCollectionView

class ViewController: UIViewController {
    @IBOutlet weak var titleLabel: UILabel!
    @IBOutlet weak var collectionView: UICollectionView!
    
    // set your original Cell to <SampleCell>
    private var dataSource: SnapLikeDataSource<SampleCell>?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // setup size of cells
        let cellSize = SnapLikeCellSize(normalWidth: 100, centerWidth: 160)
        
        // create dataSource
        dataSource = SnapLikeDataSource<SampleCell>(collectionView: collectionView, cellSize: cellSize)
        dataSource?.delegate = self
        
        // create FlowLayout
        let layout = SnapLikeCollectionViewFlowLayout(cellSize: cellSize)
        collectionView.collectionViewLayout = layout
        
        // setup collectionView like this
        collectionView.registerNib(SampleCell.self)
        collectionView.showsHorizontalScrollIndicator = false
        collectionView.decelerationRate = .fast
        collectionView.delegate = dataSource
        collectionView.dataSource = dataSource
        
        // pass arrays which type is decided `Item` in the SampleCell.
        dataSource?.items = ["A", "B", "C", "D", "E"]
    }
}

// listen selected listener
extension ViewController: SnapLikeDataDelegate {
    func cellSelected(_ index: Int) {
        DispatchQueue.main.async { [weak self] in
            let selectedItem: String = self?.dataSource?.items[index] ?? ""
            self?.titleLabel.text = selectedItem
        }
    }
}