STWCollectionView is an UICollectionView sublcass easy to create and manage for a collection with carousel effect and is very simple to customize.
You can set how many cells are visible simultaneously or give a fixed size to cells, and the collection will set automatically the simultaneously visible cells.
You can set the space between the cells and the vertical and horizontal padding than you can see a bit of the adjacent cells.
Further, STWCollectionView has a delegate to better manage cells during the scrolling phase such as: the cell's currently visible indexPaths and their percentage of positioning based on the center.

Installation

CocoaPods:

pod 'STWCollectionView'

Usage

Set as you would an UICollectionView

let stwCollectionView = STWCollectionView()

override func viewDidLoad() {
  super.viewDidLoad()

  // delegate & data source
  stwCollectionView.delegate = self
  stwCollectionView.dataSource = self

  // layout subviews
  ...

  // register collection cells
  stwCollectionView.register(UICollectionViewCell.self, forCellWithReuseIdentifier: cellIdentifier)

}

// datasource extensions
...

Delegation

In addition to the UICollectionViewDelegate methods, STWCollectionView has three other methods to manage scrolling thanks to STWCollectionViewDelegate that is a UICollectionViewDelegate protocol subclass

extension ViewController: STWCollectionViewDelegate {

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
		// Scroll to selected cell
        stwCollectionView.scrollTo(indexPath: indexPath, animated: true)
    }
    
    func collectionViewDidEndDeceleratingWithPercentages(_ collectionView: STWCollectionView, visibleIndexPaths indexPaths: [IndexPath], percentageVisibleIndexPaths percentages: [CGFloat]) {
        print("indexPaths after Decelerating: \(indexPaths)")
        print("percentages after Decelerating: \(percentages)")
    }
    
    func collectionViewDidEndScrollingAnimationWithPercentages(_ collectionView: STWCollectionView, visibleIndexPaths indexPaths: [IndexPath], percentageVisibleIndexPaths percentages: [CGFloat]) {
        print("indexPaths after Scrolling Animation: \(indexPaths)")
        print("percentages after Scrolling Animation: \(percentages)")
    }
    
    func collectionViewDidScrollWithPercentages(_ collectionView: STWCollectionView, visibleIndexPaths indexPaths: [IndexPath], percentageVisibleIndexPaths percentages: [CGFloat]) {
        print("indexPaths during Scrolling: \(indexPaths)")
        print("percentages during Scrolling: \(percentages)")        
    }
}

Customize

You can customize STWCollectionView for all your needs

STWCollectionView setting properties:

• verticalPadding Distance of cells form top and bottom border.
  ❕ Disabled if the STWCollectionView is in horizontal and has a fixedCellSize

  var verticalPadding: CGFloat { get set }
  // default: 20

• horizontalPadding Distance of cells form left and right border.
  ❕ Disabled if the STWCollectionView is in vertical and has a fixedCellSize

  var horizontalPadding: CGFloat { get set }
  // default: 20

• itemSpacing Distance beetween cells.

  var itemSpacing: CGFloat { get set }
  // default: 20

• fixedCellsNumber Numbers of simultaneous visible cells.
  ❕ Sets fixedCellSize to nil when is setted

  var fixedCellsNumber: Int { get set }
  // default: 1
  

• fixedCellSize Fixed size of cells.
  ❕ Automatically calculates fixedCellsNumber when is setted

  var fixedCellSize: CGSize? { get set }
  

• forceCentered Force the contentInset of STWCollectionView so that first and last items are centered.
  ❕ Work only with fixedCellSize setted

  var forceCentered: Bool { get set }
  // default: false
  

• direction Direction of scrolling.
  (supports vertical)

  var direction: UICollectionViewScrollDirection { get set }
  // default: .horizontal
  

STWCollectionView getting properties:

• currentVisibleIndexPaths Current visible items' indexPaths.

  var currentVisibleIndexPaths: [IndexPath] { get }
  

• currentPage Current Index in center.
  ❕ if fixedCellsNumber are even the result is a CGFloat beetween two value

  var currentPage: CGFloat { get }
  

STWCollectionView public methods:

• scrollTo(indexPath: animated:) Scrolls STWCollectionView at specific indexPath.

  func scrollTo(indexPath:IndexPath, animated:Bool)
  

Requirements

This pod requires a deployment target of iOS 9.0 or greater

Author

@Steewitter, [email protected]

License

STWCollectionView is available under the MIT license. See the LICENSE file for more info.