效果圖

原理:給collectionView設定多組一樣的資料,預設展示中間的那一組.當滾動到上一組或者下一組的時候採用無動畫的方式滾動到最中間的那一組.這樣就實現了檢視的無限輪播.

class MCCycleView: UIView, UICollectionViewDelegate, UICollectionViewDataSource {

    private var collectionView: UICollectionView!
    private var pageControl: UIPageControl!
    private var timer: Timer?

    lazy var picArr: [UIImage] = {
        return [UIImage(named: "1"
 
)!,
                UIImage(named: "2")!,
                UIImage(named: "3")!,
                UIImage(named: "4")!,
                UIImage(named: "5")!]
    }()


    private let CycleReuseIdentifier = "CycleReuseIdentifier"
    //組數 多少組都可以最少三組
    private let MaxSections = 3

    override init(frame: CGRect) {
        super.init
 
(frame: frame)
        setup()
    }

    private func setup() {
        //設定flowLayout屬性
        let flowLayout = UICollectionViewFlowLayout()
        flowLayout.itemSize = CGSize(width: UIScreen.main.bounds.width, height: 150)
        flowLayout.minimumLineSpacing = 0
        flowLayout.minimumInteritemSpacing
 
 = 0
        flowLayout.scrollDirection = .horizontal
        collectionView = UICollectionView(frame: frame, collectionViewLayout: flowLayout)
        collectionView.isPagingEnabled = true
        collectionView.register(MCCycleCell.self, forCellWithReuseIdentifier: CycleReuseIdentifier)
        collectionView.delegate = self
        collectionView.dataSource = self
        //預設滾動到中間的那一組
        collectionView.scrollToItem(at: IndexPath(item: 0, section: MaxSections / 2), at: .left, animated: false)
        addSubview(collectionView)

        pageControl = UIPageControl()
        pageControl.numberOfPages = picArr.count
        pageControl.currentPageIndicatorTintColor = UIColor.orange
        addSubview(pageControl)

        //新增定時器
        addTimer()

        //設定collectionView和pageControl的約束
        collectionView.snp.makeConstraints { (make) in
            make.top.equalTo(self.snp.top)
            make.left.equalTo(self.snp.left)
            make.bottom.equalTo(self.snp.bottom)
            make.right.equalTo(self.snp.right)
        }

        pageControl.snp.makeConstraints { (make) in
            make.right.equalTo(self.snp.right).offset(-10)
            make.bottom.equalTo(self.snp.bottom).offset(-10)
        }
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

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

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

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: CycleReuseIdentifier, for: indexPath) as! MCCycleCell
        cell.img = picArr[indexPath.item]

        return cell
    }

    //在這個方法中算出當前頁數
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        let page = Int((scrollView.contentOffset.x + (collectionView?.bounds.width)! * 0.5) / (collectionView?.bounds.width)!)
        let currentPage = page % picArr.count
        pageControl?.currentPage = currentPage
    }

    //在開始拖拽的時候移除定時器
    func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
        timer?.invalidate()
        timer = nil
    }

    //結束拖拽的時候重新新增定時器
    func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {
        addTimer()
    }

    //手動滑動
    func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
        collectionView.scrollToItem(at: IndexPath(item: pageControl.currentPage, section: 1), at: .left, animated: false)
    }

    private func addTimer() {
        timer = Timer(timeInterval: 3, target: self, selector: #selector(nextImage), userInfo: nil, repeats: true)
        RunLoop.current.add(timer!, forMode: .commonModes)
    }

    @objc private func nextImage() {
        //獲取當前indexPath
        let currentIndexPath = collectionView.indexPathsForVisibleItems.last!
        //獲取中間那一組的indexPath
        let middleIndexPath = IndexPath(item: currentIndexPath.item, section: 1)
        //滾動到中間那一組
        collectionView.scrollToItem(at: middleIndexPath, at: .left, animated: false)

        var nextItem = middleIndexPath.item + 1
        var nextSection = middleIndexPath.section
        if nextItem == picArr.count {
            nextItem = 0
            nextSection += 1
        }
        collectionView.scrollToItem(at: IndexPath(item: nextItem, section: nextSection), at: .left, animated: true)
    }

}

class MCCycleCell: UICollectionViewCell {

    private var ImgView: UIImageView = UIImageView()

    var img: UIImage? {
        didSet {
            ImgView.image = img
        }
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
        addSubview(ImgView)
        ImgView.snp.makeConstraints { (make) in
            make.top.equalTo(self.snp.top)
            make.left.equalTo(self.snp.left)
            make.bottom.equalTo(self.snp.bottom)
            make.right.equalTo(self.snp.right)
        }
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

}