50 lines
2.4 KiB
Swift
50 lines
2.4 KiB
Swift
import UIKit
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/// UICollectionView 数据源和自定义布局代理实现
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/// 处理水平滚动和垂直滚动两种翻页模式
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extension RDReaderView: UICollectionViewDataSource, RDReaderFlowLayoutDelegate, RDReaderFlowLayoutDataSoure {
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/// 配置 UICollectionViewCell
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/// 通过 DataSource 获取页面内容视图，支持 cell 复用和预加载视图复用
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/// RTL 水平模式下翻转 cell 内容使文字方向正常
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public func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
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if let identifer = pageReuseIdentifier(for: indexPath.row) {
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let cell = collectionView.dequeueReusableCell(withReuseIdentifier: identifer, for: IndexPath(item: indexPath.row, section: 0)) as! RDReaderContentCell
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let preloadedView = preloadController.takePreloadedView(for: indexPath.row)
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let reusableView = cell.containerView ?? preloadedView
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cell.containerView = contentViewForPage(indexPath.row, reusableView: reusableView)
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// RTL 水平模式：翻转 cell 内容使文字方向正常（collectionView 已整体翻转）
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if pageDirection == .rightToLeft && currentDisplayType != .verticalScroll {
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cell.contentView.transform = CGAffineTransform(scaleX: -1, y: 1)
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} else {
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cell.contentView.transform = .identity
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}
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return cell
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}
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let cell = collectionView.dequeueReusableCell(withReuseIdentifier: NSStringFromClass(UICollectionViewCell.self), for: indexPath)
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return cell
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}
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/// 返回每组的 item 数量，即总页数
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public func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
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return numberOfPages()
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}
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/// 布局代理回调：当前可见页码变化时通知
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public func pageNum(flowLayout: RDReaderFlowLayout, pageIndex: Int) {
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if currentPage >= 0, currentPage != pageIndex {
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predictedPageDirection = pageIndex >= currentPage
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}
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currentPage = pageIndex
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primePageCache(around: pageIndex, preferredForward: predictedPageDirection)
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}
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/// 布局数据源回调：返回垂直滚动模式下指定页的高度
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/// 当前返回 nil 使用默认高度
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public func heigtOfVerticalScrollPage(flowLayout: RDReaderFlowLayout, pageIndex: Int) -> CGFloat? {
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return nil
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}
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}
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