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Infinite-LoopView
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| import UIKit | |
| final class InfiniteLoopView<T, Cell>: UIView, | |
| UICollectionViewDelegate, | |
| UICollectionViewDataSource, | |
| UICollectionViewDelegateFlowLayout | |
| where Cell: UICollectionViewCell { | |
| private lazy var collectionView: UICollectionView = { | |
| let collectionViewLayout = UICollectionViewFlowLayout() | |
| collectionViewLayout.scrollDirection = .horizontal | |
| collectionViewLayout.minimumLineSpacing = 0 | |
| let view = UICollectionView(frame: .zero, collectionViewLayout: collectionViewLayout) | |
| view.backgroundColor = .clear | |
| view.contentInset = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0) | |
| view.register(Cell.self, | |
| forCellWithReuseIdentifier: String(describing: Cell.self)) | |
| view.delegate = self | |
| view.dataSource = self | |
| view.showsVerticalScrollIndicator = false | |
| view.showsHorizontalScrollIndicator = false | |
| view.isPagingEnabled = true | |
| return view | |
| }() | |
| // MARK: data source | |
| /// 輪播畫面 | |
| var inputDatas = [T]() { didSet { dataSourceDidChange() } } | |
| /// 輪播秒數 | |
| var changeSec: Int? = nil { didSet { restartTimer() } } | |
| /// 設置外部 page viewControl (numberOfPages, currentPage) | |
| var pageIndexHandler: ((Int, Int) -> Void)? | |
| /// 設置 cell 和 資料型別 | |
| var configure: (T, Cell) -> Void | |
| /// 點擊 cell 觸發事件 | |
| var selectHandler: ((Int) -> Void)? | |
| private var currentPage = Int() | |
| private var collectionInputDatas = [T]() | |
| private var timer: Timer? | |
| private let itemSize: CGSize | |
| // Life cycle | |
| init(itemSize: CGSize, configure: @escaping (T, Cell) -> Void) { | |
| self.itemSize = itemSize | |
| self.configure = configure | |
| super.init(frame: .zero) | |
| setupUI() | |
| } | |
| required init?(coder aDecoder: NSCoder) { fatalError() } | |
| deinit { cleanTimer() } | |
| // MARK: Helper Method | |
| private func dataSourceDidChange() { | |
| guard | |
| let firstItem = inputDatas.first, | |
| let lastItem = inputDatas.last | |
| else { | |
| return | |
| } | |
| collectionInputDatas = [lastItem] + inputDatas + [firstItem] | |
| UIView.animate(withDuration: 0, animations: { | |
| self.collectionView.reloadData() | |
| }) { _ in | |
| self.collectionView.setContentOffset(CGPoint(x: UIScreen.main.bounds.width, y: 0), animated: false) | |
| self.pageIndexHandler?(self.inputDatas.count, 0) | |
| self.collectionView.isScrollEnabled = self.inputDatas.count != 1 | |
| } | |
| } | |
| private func startTimer() { | |
| guard let changeSec = changeSec else { return } | |
| timer = Timer.scheduledTimer( | |
| timeInterval: TimeInterval(changeSec), | |
| target: self, | |
| selector: #selector(scrollToNext), | |
| userInfo: nil, | |
| repeats: true | |
| ) | |
| } | |
| private func cleanTimer() { | |
| timer?.invalidate() | |
| timer = nil | |
| } | |
| private func restartTimer() { | |
| cleanTimer() | |
| startTimer() | |
| } | |
| @objc private func scrollToNext() { | |
| if !(collectionView.isScrollEnabled) { | |
| return | |
| } | |
| let x = CGFloat(Int(UIScreen.main.bounds.width) * (currentPage + 1)) | |
| collectionView.setContentOffset(CGPoint(x: x, y: 0), animated: true) | |
| } | |
| @objc private func scroll(to index: Int) { | |
| if index == 0 { // 滑到 index 0 時, 把 index 改成 last | |
| let x = CGFloat(Int(UIScreen.main.bounds.width) * (collectionInputDatas.count - 2)) | |
| collectionView.setContentOffset(CGPoint(x: x, y: 0), animated: false) | |
| } else if index == collectionInputDatas.count - 1 { // 滑到 last index 時, 把 index 改成 1 | |
| let x = UIScreen.main.bounds.width | |
| collectionView.setContentOffset(CGPoint(x: x, y: 0), animated: false) | |
| } | |
| let setIndxe = Int(collectionView.contentOffset.x / UIScreen.main.bounds.width) | |
| pageIndexHandler?(inputDatas.count, setIndxe - 1) | |
| currentPage = setIndxe | |
| } | |
| // MARK: - UICollectionViewDelegate | |
| func scrollViewDidScroll(_ scrollView: UIScrollView) { | |
| if scrollView.frame.size.width <= 0 { | |
| return | |
| } | |
| // 原始資料 | |
| let pageFloat = (scrollView.contentOffset.x / scrollView.frame.size.width) | |
| // 無條件捨去 | |
| let pageInt = Int(pageFloat) | |
| // 無條件進位 | |
| let pageCeil = Int(ceil(pageFloat)) | |
| if pageInt == 0 { | |
| scroll(to: pageCeil) | |
| } else { | |
| scroll(to: pageInt) | |
| } | |
| } | |
| func scrollViewWillBeginDragging(_ scrollView: UIScrollView) { | |
| cleanTimer() | |
| } | |
| func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) { | |
| startTimer() | |
| } | |
| func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) { | |
| var index = indexPath.row - 1 | |
| index = max(-1, index) | |
| index = min(index, inputDatas.count - 1) | |
| selectHandler?(index) | |
| } | |
| // MARK: - UICollectionViewDataSource | |
| func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int { | |
| return collectionInputDatas.count | |
| } | |
| func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell { | |
| guard | |
| let cell = collectionView.dequeueReusableCell(withReuseIdentifier: String(describing: Cell.self), for: indexPath) as? Cell | |
| else { | |
| return UICollectionViewCell() | |
| } | |
| let item = collectionInputDatas[indexPath.row] | |
| configure(item, cell) | |
| return cell | |
| } | |
| // MARK: - UICollectionViewDelegateFlowLayout | |
| func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize { | |
| return itemSize | |
| } | |
| func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets { | |
| return UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0) | |
| } | |
| // MARK: - Setup UI | |
| private func setupUI() { | |
| backgroundColor = .clear | |
| addSubview(collectionView) | |
| NSLayoutConstraint.activate([ | |
| collectionView.leadingAnchor.constraint(equalTo: leadingAnchor), | |
| collectionView.topAnchor.constraint(equalTo: topAnchor), | |
| collectionView.trailingAnchor.constraint(equalTo: trailingAnchor), | |
| collectionView.bottomAnchor.constraint(equalTo: bottomAnchor), | |
| collectionView.heightAnchor.constraint(equalToConstant: itemSize.height), | |
| collectionView.widthAnchor.constraint(equalToConstant: itemSize.width) | |
| ]) | |
| } | |
| } |
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