How to add PageControl inside UICollectionView Image Scrolling

Question

I have UICollectionView Horizontal Image listing codes. I want to add PageControl when scrolling images will shows, I added pagecontrol selector and IBOutlet but how can I integrate it between UICollecitonView?

My codes are below:

 class  ViewController: UIViewController,  UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {


    @IBOutlet weak var View : DesignableView!


    @IBOutlet var collectionView: UICollectionView!
    @IBOutlet var collectionViewLayout: UICollectionViewFlowLayout!

    @IBOutlet open weak var pageControl: UIPageControl? {
        didSet {
            pageControl?.addTarget(self, action: #selector(ViewController.pageChanged(_:)), for: .valueChanged)
        }
    }

    override func viewDidLoad() {
        super.viewDidLoad()

         pageControl?.numberOfPages = 11


    }


    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 11;
    }




    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell: ImageCollectionViewCell = collectionView.dequeueReusableCell(withReuseIdentifier: "ImageCollectionViewCell", for: indexPath) as! ImageCollectionViewCell
        cell.label.text = "Cell \(indexPath.row)"
        cell.backgroundImageView.image = UIImage(named: "Parallax \(indexPath.row + 1)")

        // Parallax cell setup
        cell.parallaxTheImageViewScrollOffset(self.collectionView.contentOffset, scrollDirection: self.collectionViewLayout.scrollDirection)
        return cell
    }



    @IBAction open func pageChanged(_ sender: UIPageControl) {

        print(sender.currentPage)


    }




    // MARK: Delegate

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        return collectionView.bounds.size;
    }

    // MARK: Scrolling

    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        // Parallax visible cells
        for cell: ImageCollectionViewCell in collectionView.visibleCells as! [ImageCollectionViewCell] {
            cell.parallaxTheImageViewScrollOffset(self.collectionView.contentOffset, scrollDirection: self.collectionViewLayout.scrollDirection)
        }
    }


    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }



}

Answer 1

I'm not a fan of the accepted answer. From time to time, willDisplay cell will return the wrong page for the page control depending on users interaction.

What I use:

func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
    pageControl.currentPage = Int(scrollView.contentOffset.x) / Int(scrollView.frame.width)
}

This will update the page after the user has finished scrolling thus making the currentPage of the pageControl more accurate.

Answer 2

Here you have a complete class with Page Control pagination in a horizontal collection view. This is working on one of my applications, right now, and is working correctly. If you cannot get it work, do feel free to ask me and I'll help you.

First, in the Storyboard you have to set up your CollectionView with:

Layout: Flow
Scroll Direction: Horizontal
Scrolling enabled
Paging enabled

@IBOutlet weak var collectionView: UICollectionView! //img: 77

@IBOutlet weak var pageControl: UIPageControl!

var thisWidth:CGFloat = 0

override func awakeFromNib() {
    super.awakeFromNib()

    thisWidth = CGFloat(self.frame.width)
    collectionView.delegate = self
    collectionView.dataSource = self

    pageControl.hidesForSinglePage = true

}

func numberOfSections(in collectionView: UICollectionView) -> Int {
    return 10
}

func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return 1
}

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "YourCell", for: indexPath)

    return cell
}

func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
    self.pageControl.currentPage = indexPath.section
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
    thisWidth = CGFloat(self.frame.width)
    return CGSize(width: thisWidth, height: self.frame.height)
}

Answer 3

For a more responsive UIPageControl, I prefer to use scrollViewDidScroll and calculating the offset with regards to the horizontal center of the scrollView.

func scrollViewDidScroll(_ scrollView: UIScrollView) {
    let offSet = scrollView.contentOffset.x
    let width = scrollView.frame.width
    let horizontalCenter = width / 2

    pageControl.currentPage = Int(offSet + horizontalCenter) / Int(width)
}

Answer 4

Swift 5 Very Smooth working

//MARK:- For Display the page number in page controll of collection view Cell
func scrollViewDidScroll(_ scrollView: UIScrollView) {
    let visibleRect = CGRect(origin: self.collectionview.contentOffset, size: self.collectionview.bounds.size)
    let visiblePoint = CGPoint(x: visibleRect.midX, y: visibleRect.midY)
    if let visibleIndexPath = self.collectionview.indexPathForItem(at: visiblePoint) {
        self.pageControl.currentPage = visibleIndexPath.row
    }
}