1330 lines
58 KiB
Swift
1330 lines
58 KiB
Swift
//
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// RDReaderView.swift
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// RDReaderDemo
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//
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// Created by yangsq on 2021/8/6.
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//
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// 文件职责：核心翻页容器视图，RDReaderView 模块的入口和中枢。
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// 该文件定义了阅读器的核心 UIView 子类 RDReaderView，负责：
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// 1. 管理四种翻页模式（仿真翻页、水平滚动、垂直滚动、水平覆盖滚动）
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// 2. 实现手势分区逻辑（左1/3上一页、中1/3工具栏、右1/3下一页）
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// 3. 支持横屏双页显示（含封面页独占和页码配对算法）
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// 4. 支持从左往右(LTR)和从右往左(RTL)两种翻页方向
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// 5. 提供 DataSource/Delegate 协议供上层控制器实现数据供给和事件回调
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// 6. 管理页面预加载和缓存机制
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//
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// 架构位置：RDReaderView 四层架构中的第三层（翻页容器层）
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// EPUBCore（解析引擎）→ EPUBTextRendering（文本渲染）→ RDReaderView（翻页容器）→ EPUBUI（读者 UI）
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//
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import UIKit
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/// 阅读器数据源协议
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/// 上层控制器通过实现此协议，向 RDReaderView 提供页面数量、内容视图和工具栏。
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/// 所有方法由 RDReaderView 在需要渲染页面时回调。
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@objc public protocol RDReaderDataSource: NSObjectProtocol {
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/// 返回阅读器的总页数
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/// - Parameter readerView: 发起请求的阅读器视图
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/// - Returns: 总页数
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func pageCountOfReaderView(readerView: RDReaderView) -> Int
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/// 返回指定页码的内容视图
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/// - Parameters:
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/// - readerView: 发起请求的阅读器视图
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/// - pageNum: 页码（从0开始）
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/// - containerView: 可复用的容器视图（非 nil 时可复用以减少创建开销）
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/// - Returns: 该页的内容视图
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func pageContentView(readerView: RDReaderView, pageNum: Int, containerView: UIView?) -> UIView
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/// 返回指定页码的唯一标识符，用于 UICollectionViewCell 复用
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/// - Parameters:
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/// - readerView: 发起请求的阅读器视图
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/// - pageNum: 页码
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/// - Returns: 页标识符字符串，nil 则使用默认 cell
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func pageIdentifier(readerView: RDReaderView, pageNum: Int) -> String?
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/// 返回顶部工具栏视图（可选），点击屏幕中央时会显示/隐藏
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@objc optional func topToolView(readerView: RDReaderView) -> UIView?
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/// 返回底部工具栏视图（可选），点击屏幕中央时会显示/隐藏
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@objc optional func bottomToolView(readerView: RDReaderView) -> UIView?
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}
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/// 阅读器代理协议
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/// 上层控制器通过实现此协议，接收翻页和横竖屏切换事件
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@objc public protocol RDReaderDelegate: NSObjectProtocol {
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/// 翻页回调，当当前显示页码变化时触发
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/// - Parameters:
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/// - readerView: 发起回调的阅读器视图
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/// - pageNum: 当前页码
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func pageNum(readerView: RDReaderView, pageNum: Int)
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/// 横竖屏切换时回调，可在此重新分页
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@objc optional func readerViewOrientationWillChange(readerView: RDReaderView, isLandscape: Bool)
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}
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extension RDReaderView {
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/// 翻页模式枚举，决定 RDReaderView 使用哪种底层视图来展示内容
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public enum DisplayType {
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/// 仿真翻页：使用 UIPageViewController，模拟真实翻书效果
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case pageCurl
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/// 水平滚动：使用 UICollectionView + 自定义布局，每屏一项，水平分页
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case horizontalScroll
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/// 垂直滚动：使用 UICollectionView，全宽项目，垂直连续滚动
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case verticalScroll
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}
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/// 翻页方向枚举
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public enum PageDirection {
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/// 从左往右翻页（默认，适用于中文/英文书籍）
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case leftToRight
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/// 从右往左翻页（适用于日文漫画等）
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case rightToLeft
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}
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}
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/// 核心翻页容器视图
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/// RDReaderView 模块的核心类，负责管理四种翻页模式的切换、手势识别、
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/// 横屏双页显示、页面缓存预加载等核心功能。
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///
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/// 使用方式：
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/// 1. 设置 ``dataSource`` 提供页面数据
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/// 2. 设置 ``delegate`` 接收翻页事件
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/// 3. 调用 ``switchReaderDisplayType(_:)`` 切换翻页模式
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/// 4. 调用 ``reloadData()`` 刷新数据
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///
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/// 支持的功能：
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/// - 四种翻页模式：pageCurl / horizontalScroll / verticalScroll
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/// - 横屏双页显示（含封面页独占逻辑）
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/// - RTL 翻页方向支持
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/// - 手势分区（左翻/工具栏/右翻）
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/// - 页面预加载和缓存
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public class RDReaderView: UIView {
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/// 屏幕点击区域枚举，用于手势分区逻辑
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/// 将屏幕水平三等分，分别响应不同的手势事件
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enum TapEvent {
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/// 无操作
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case none
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/// 左1/3区域：上一页（RTL 时为下一页）
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case left
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/// 中1/3区域：切换工具栏显示/隐藏
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case center
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/// 右1/3区域：下一页（RTL 时为上一页）
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case right
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}
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/// 仿真翻页模式使用的 UIPageViewController
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/// 通过 pageCurl 转场样式实现仿真翻书效果
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private lazy var pageViewController: UIPageViewController = {
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let pageVC = UIPageViewController(transitionStyle: .pageCurl, navigationOrientation: .horizontal, options: nil)
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pageVC.delegate = self
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pageVC.dataSource = self
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return pageVC
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}()
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/// 自定义流式布局，支持水平滚动、垂直滚动和水平覆盖滚动三种布局模式
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private lazy var layout: RDReaderFlowLayout = {
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let layout = RDReaderFlowLayout(displayType: .horizontalScroll)
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layout.dataSource = self
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layout.delegate = self
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return layout
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}()
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/// 滚动模式使用的 UICollectionView
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/// 用于 horizontalScroll 和 verticalScroll 两种翻页模式
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private lazy var collectionView: UICollectionView = {
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let collectionView = UICollectionView(frame: .zero, collectionViewLayout: layout)
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collectionView.backgroundColor = UIColor.clear
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return collectionView
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}()
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/// 当前显示的页码
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/// 值变化时会通过 delegate 回调通知上层控制器
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/// 初始值为 -1 表示尚未加载任何页面
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public var currentPage: Int = -1 {
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didSet {
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if let delegate = delegate, currentPage != oldValue, delegate.responds(to: #selector(RDReaderDelegate.pageNum(readerView:pageNum:))) {
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delegate.pageNum(readerView: self, pageNum: currentPage)
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}
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}
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}
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/// 全屏点击手势识别器
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/// 用于检测用户点击屏幕的区域，触发翻页或工具栏切换
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private(set) lazy var tapGestureRecognizer: UITapGestureRecognizer = {
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let tap = UITapGestureRecognizer(target: self, action: #selector(tapAction(tap:)))
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return tap
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}()
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/// 当前点击事件类型
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/// 值变化时会根据事件类型执行翻页或工具栏切换逻辑
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private var tapEvent: TapEvent = .none {
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didSet {
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let isRTL = pageDirection == .rightToLeft
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switch tapEvent {
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case .left:
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if currentDisplayType != .pageCurl {
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if isRTL { goNextPage() } else { goPreviousPage() }
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}
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case .right:
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if currentDisplayType != .pageCurl {
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if isRTL { goPreviousPage() } else { goNextPage() }
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}
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case .center:
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tapCenter()
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default:
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break
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}
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}
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}
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/// 翻到下一页
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/// 在双页模式下使用 adjacentDualPage 计算目标页码，单页模式直接 +1
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private func goNextPage() {
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let totalPages = dataSource?.pageCountOfReaderView(readerView: self) ?? 0
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if pagesPerScreen > 1 {
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if let target = adjacentDualPage(from: currentPage, forward: true) {
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transitionToPage(pageNum: target, animated: true)
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}
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} else if currentPage + 1 < totalPages {
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transitionToPage(pageNum: currentPage + 1, animated: true)
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}
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}
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/// 翻到上一页
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/// 在双页模式下使用 adjacentDualPage 计算目标页码，单页模式直接 -1
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private func goPreviousPage() {
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if pagesPerScreen > 1 {
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if let target = adjacentDualPage(from: currentPage, forward: false) {
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transitionToPage(pageNum: target, animated: true)
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}
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} else if currentPage - 1 >= 0 {
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transitionToPage(pageNum: currentPage - 1, animated: true)
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}
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}
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/// 数据源代理，提供页面数量、内容视图和工具栏
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public weak var dataSource: RDReaderDataSource? = nil
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/// 代理，接收翻页和横竖屏切换事件
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public weak var delegate: RDReaderDelegate? = nil
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/// 当前翻页模式，默认为仿真翻页
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public var currentDisplayType: RDReaderView.DisplayType = .pageCurl
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/// 工具栏显示/隐藏动画时长，默认 0.3 秒
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public var toolViewAnimationDuration: TimeInterval = 0.3
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/// 是否启用横屏双页显示
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public var landscapeDualPageEnabled: Bool = false
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/// 翻页方向，默认从左往右（适用于中文/英文书籍）
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public var pageDirection: RDReaderView.PageDirection = .leftToRight
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/// 横屏双页模式下，封面页的索引。设置后该页在横屏时独占一屏，后续页面两两配对。
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/// 设为 nil 表示没有封面页（所有页面正常两两配对：0+1, 2+3, 4+5...）。
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public var coverPageIndex: Int? = nil
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/// 是否启用了封面页独占
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private var hasCoverPage: Bool {
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return coverPageIndex != nil
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}
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/// 当前是否横屏（宽度 > 高度）
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private var isLandscape: Bool {
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return bounds.width > bounds.height
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}
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/// 每屏显示的页数
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/// 未启用双页、垂直滚动模式或竖屏时返回1，横屏双页模式返回2
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public var pagesPerScreen: Int {
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if !landscapeDualPageEnabled { return 1 }
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if currentDisplayType == .verticalScroll { return 1 }
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return isLandscape ? 2 : 1
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}
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/// 判断某页在横屏双页模式下是否独占一屏（封面页）
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/// - Parameter pageNum: 页码
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/// - Returns: 是否独占一屏
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public func isFullScreenPage(_ pageNum: Int) -> Bool {
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guard landscapeDualPageEnabled, isLandscape, let coverIndex = coverPageIndex else { return false }
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return pageNum == coverIndex
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}
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/// 根据逻辑页码计算横屏双页模式下的配对信息
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/// 封面页独占一屏，后续页面两两配对
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/// - Parameter pageNum: 逻辑页码
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/// - Returns: (左页码, 右页码(可选，nil表示右页为空白))
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private func dualPagePair(for pageNum: Int) -> (left: Int, right: Int?) {
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let totalPages = dataSource?.pageCountOfReaderView(readerView: self) ?? 0
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if let coverIndex = coverPageIndex {
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if pageNum == coverIndex {
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// 封面页独占一屏
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return (coverIndex, nil)
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}
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// 封面之后的页面：偏移1后两两配对
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// 例如封面是0页，则 1+2, 3+4, 5+6...
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let adjustedIndex = pageNum - (coverIndex + 1) // 跳过封面后的偏移
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let pairStart = coverIndex + 1 + (adjustedIndex / 2) * 2
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let left = pairStart
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let right = pairStart + 1 < totalPages ? pairStart + 1 : nil
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return (left, right)
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} else {
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// 无封面页：正常两两配对 0+1, 2+3, 4+5...
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let left = (pageNum / 2) * 2
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let right = left + 1 < totalPages ? left + 1 : nil
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return (left, right)
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}
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}
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/// 计算横屏双页下，某页往前/后翻一屏后的起始页码
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/// - Parameters:
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/// - pageNum: 当前页码
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/// - forward: 是否向后翻（true=下一页，false=上一页）
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/// - Returns: 目标页码，nil 表示到头了
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private func adjacentDualPage(from pageNum: Int, forward: Bool) -> Int? {
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let totalPages = dataSource?.pageCountOfReaderView(readerView: self) ?? 0
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let pair = dualPagePair(for: pageNum)
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if forward {
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let nextStart = (pair.right ?? pair.left) + 1
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return nextStart < totalPages ? nextStart : nil
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} else {
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let prevEnd = pair.left - 1
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guard prevEnd >= 0 else { return nil }
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return dualPagePair(for: prevEnd).left
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}
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}
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/// 将页码钳制到当前书籍的合法范围内
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private func clampedPageNumber(_ pageNum: Int) -> Int? {
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let totalPages = dataSource?.pageCountOfReaderView(readerView: self) ?? 0
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guard totalPages > 0 else { return nil }
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return min(max(pageNum, 0), totalPages - 1)
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}
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/// 上一次检测到的横竖屏状态，用于在 layoutSubviews 中检测方向变化
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private var previousIsLandscape: Bool?
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/// 已注册的内容视图类型字典，key 为重用标识符
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private var contentViews = [String : UIView.Type]()
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/// pageCurl 模式下，即将向前翻转到的子控制器
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private var willPreviousTransitionToViewController: UIViewController? = nil
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/// pageCurl 模式下，即将向后翻转到的子控制器
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private var willNextTransitionToViewController: UIViewController? = nil
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/// pageCurl 模式下，正在转场的目标控制器
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private var willTransitionToViewController: UIViewController? = nil
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/// 顶部工具栏视图
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private var topToolView: UIView?
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/// 底部工具栏视图
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private var bottomToolView: UIView?
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/// 工具栏是否正在显示
|
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private var isShowToolView: Bool = false
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/// 是否正在执行页面转场动画
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private var isTransitioning: Bool = false
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/// UI 是否已经构建完成（避免重复构建）
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private var didBuildUI = false
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/// 预加载宿主视图（隐藏不可见），用于存放预加载的页面内容
|
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private let preloadHostView = UIView()
|
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/// 预加载的页面视图缓存，key 为页码
|
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private var preloadedPageViews: [Int: UIView] = [:]
|
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/// pageCurl 模式下的页面视图缓存，key 为页码
|
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private var pageCurlCachedViews: [Int: UIView] = [:]
|
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/// 预测的翻页方向（true=向前，false=向后），用于优化预加载方向
|
||
private var predictedPageDirection: Bool?
|
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/// 预加载半径：当前页前后各预加载几屏，默认 1 屏
|
||
public var preloadRadius: Int = 1
|
||
/// 缓存签名：用于检测布局环境是否变化，变化时需要清空缓存
|
||
private var cacheSignature: CacheSignature?
|
||
|
||
/// 用于 pageCurl 双页模式下封面页旁边的空白页标识
|
||
static let blankPageNum = Int.max
|
||
/// 用于 pageCurl 双页模式下末尾不成对页旁边的空白页标识
|
||
static let blankEndPageNum = Int.max - 1
|
||
|
||
/// 缓存签名结构体
|
||
/// 当这些参数中的任何一个发生变化时，缓存需要被清空并重建
|
||
private struct CacheSignature: Equatable {
|
||
/// 当前翻页模式
|
||
let displayType: DisplayType
|
||
/// 是否横屏
|
||
let isLandscape: Bool
|
||
/// 每屏页数
|
||
let pagesPerScreen: Int
|
||
/// 视图尺寸
|
||
let boundsSize: CGSize
|
||
}
|
||
|
||
/// 当 pageCurl 正在转场时，后续跳转请求会先排队，待当前动画稳定后再执行。
|
||
private struct PageTransitionRequest: Equatable {
|
||
let pageNum: Int
|
||
let animated: Bool
|
||
}
|
||
|
||
private var pendingTransitionRequest: PageTransitionRequest?
|
||
|
||
override init(frame: CGRect) {
|
||
super.init(frame: frame)
|
||
}
|
||
|
||
/// 布局子视图时调用
|
||
/// 检测横竖屏方向变化，触发相应的布局更新和页面重建
|
||
public override func layoutSubviews() {
|
||
super.layoutSubviews()
|
||
guard bounds.width > 0, bounds.height > 0 else { return }
|
||
preloadHostView.frame = bounds
|
||
let nowLandscape = isLandscape
|
||
if let prev = previousIsLandscape, prev != nowLandscape {
|
||
previousIsLandscape = nowLandscape
|
||
// 延迟到下一个 RunLoop 执行，避免在 layoutSubviews 中嵌套触发 reloadData/layoutIfNeeded
|
||
// 造成 collectionView 中间态尺寸不一致的问题
|
||
DispatchQueue.main.async { [weak self] in
|
||
guard let self = self else { return }
|
||
self.orientationChanged(isNowLandscape: nowLandscape)
|
||
}
|
||
} else if previousIsLandscape == nil {
|
||
previousIsLandscape = nowLandscape
|
||
layout.isLandscapeDualPage = landscapeDualPageEnabled && nowLandscape
|
||
}
|
||
}
|
||
|
||
/// 横竖屏切换处理
|
||
/// 根据当前翻页模式执行不同的重建策略：
|
||
/// - pageCurl：重建 UIPageViewController（因为 spineLocation 只能在初始化时设置）
|
||
/// - 滚动模式：禁用动画，重新加载数据并恢复滚动位置
|
||
/// - Parameter isNowLandscape: 当前是否为横屏
|
||
private func orientationChanged(isNowLandscape: Bool) {
|
||
let savedPage = max(0, currentPage)
|
||
// 1. 通知代理方向变化。正文级重分页由上层控制器统一接管，这里只保留容器级刷新钩子。
|
||
delegate?.readerViewOrientationWillChange?(readerView: self, isLandscape: isNowLandscape)
|
||
// 2. 更新布局的横屏双页标记
|
||
layout.isLandscapeDualPage = landscapeDualPageEnabled && isNowLandscape
|
||
layout.coverPageIndex = coverPageIndex
|
||
|
||
switch currentDisplayType {
|
||
case .pageCurl:
|
||
// 仿真翻页：通过 spineLocation 原生支持双页，需要重建 PageViewController
|
||
rebuildPageViewController()
|
||
transitionToPage(pageNum: savedPage)
|
||
primePageCache(around: savedPage, preferredForward: predictedPageDirection)
|
||
default:
|
||
// 滚动模式：禁用动画防止旋转过渡中出现尺寸抖动
|
||
UIView.performWithoutAnimation {
|
||
// 强制使布局完全失效并重新计算
|
||
collectionView.collectionViewLayout.invalidateLayout()
|
||
collectionView.reloadData()
|
||
collectionView.layoutIfNeeded()
|
||
// 3. 根据保存的页码恢复滚动位置
|
||
let totalPages = dataSource?.pageCountOfReaderView(readerView: self) ?? 0
|
||
let safePage = min(savedPage, max(0, totalPages - 1))
|
||
let targetOffset = layout.currentContentOffset(count: safePage)
|
||
collectionView.setContentOffset(targetOffset, animated: false)
|
||
primePageCache(around: safePage, preferredForward: predictedPageDirection)
|
||
}
|
||
}
|
||
}
|
||
|
||
/// 创建带指定 spine 位置的 UIPageViewController
|
||
/// - Parameter isDualPage: 是否双页模式（横屏时书脊在中间：.mid）
|
||
/// - Returns: 配置好的 UIPageViewController 实例
|
||
private func createPageViewController(isDualPage: Bool) -> UIPageViewController {
|
||
let options: [UIPageViewController.OptionsKey: Any]?
|
||
if isDualPage {
|
||
options = [.spineLocation: NSNumber(value: UIPageViewController.SpineLocation.mid.rawValue)]
|
||
} else {
|
||
options = nil
|
||
}
|
||
let pageVC = UIPageViewController(transitionStyle: .pageCurl, navigationOrientation: .horizontal, options: options)
|
||
pageVC.delegate = self
|
||
pageVC.dataSource = self
|
||
pageVC.isDoubleSided = isDualPage
|
||
return pageVC
|
||
}
|
||
|
||
/// 重建 UIPageViewController
|
||
/// 横竖屏切换时需要重建，因为 spineLocation 只能在初始化时设置
|
||
/// 先移除旧的 PageViewController，再创建新的并添加到父控制器
|
||
private func rebuildPageViewController() {
|
||
detachPageViewControllerIfNeeded()
|
||
|
||
let isDualPage = landscapeDualPageEnabled && isLandscape
|
||
let pageVC = createPageViewController(isDualPage: isDualPage)
|
||
pageViewController = pageVC
|
||
attachPageViewControllerIfNeeded()
|
||
}
|
||
|
||
// MARK: - UIPageViewController Fault Detection
|
||
|
||
/// 检测 UIPageViewController 是否处于异常状态
|
||
/// 异常状态包括：子控制器数量不对、页码不匹配等
|
||
/// - Parameter pageVC: 要检测的 UIPageViewController
|
||
/// - Returns: true 表示存在异常，需要修复
|
||
private func detectPageViewControllerFault(_ pageVC: UIPageViewController) -> Bool {
|
||
guard currentDisplayType == .pageCurl else { return false }
|
||
let expectedCount = (landscapeDualPageEnabled && isLandscape) ? 2 : 1
|
||
guard let viewControllers = pageVC.viewControllers,
|
||
viewControllers.count == expectedCount else {
|
||
return true
|
||
}
|
||
|
||
let childViewControllers = viewControllers.compactMap { $0 as? RDReaderPageChildViewController }
|
||
guard childViewControllers.count == expectedCount else {
|
||
return true
|
||
}
|
||
|
||
if expectedCount == 1 {
|
||
return childViewControllers.first?.pageNum != currentPage
|
||
}
|
||
|
||
let expectedPair = dualPagePair(for: currentPage)
|
||
let expectedRightPage = expectedPair.right
|
||
?? (isFullScreenPage(expectedPair.left) ? RDReaderView.blankPageNum : RDReaderView.blankEndPageNum)
|
||
return childViewControllers[0].pageNum != expectedPair.left
|
||
|| childViewControllers[1].pageNum != expectedRightPage
|
||
}
|
||
|
||
/// 修复 UIPageViewController 异常状态
|
||
/// 清空缓存、重建 PageViewController 并重新定位到当前页
|
||
private func patchPageViewControllerFault() {
|
||
guard currentPage >= 0 else { return }
|
||
DispatchQueue.main.async { [weak self] in
|
||
guard let self else { return }
|
||
self.isTransitioning = false
|
||
self.pendingTransitionRequest = nil
|
||
self.willPreviousTransitionToViewController = nil
|
||
self.willNextTransitionToViewController = nil
|
||
self.willTransitionToViewController = nil
|
||
self.invalidatePageCaches()
|
||
self.rebuildPageViewController()
|
||
self.transitionToPage(pageNum: self.currentPage, animated: false)
|
||
}
|
||
}
|
||
|
||
/// pageCurl 动画过程中如果收到新的跳转请求，则排队等待当前动画结束。
|
||
private func shouldQueuePageTransition(_ request: PageTransitionRequest) -> Bool {
|
||
guard currentDisplayType == .pageCurl, isTransitioning else { return false }
|
||
pendingTransitionRequest = request
|
||
return true
|
||
}
|
||
|
||
/// 收尾 pageCurl 转场，并尝试执行排队中的后续跳转。
|
||
private func finishPageCurlTransition(repairFaultIfNeeded: Bool = true) {
|
||
isTransitioning = false
|
||
willPreviousTransitionToViewController = nil
|
||
willNextTransitionToViewController = nil
|
||
willTransitionToViewController = nil
|
||
|
||
if repairFaultIfNeeded, detectPageViewControllerFault(pageViewController) {
|
||
patchPageViewControllerFault()
|
||
return
|
||
}
|
||
|
||
guard let pendingTransitionRequest else { return }
|
||
self.pendingTransitionRequest = nil
|
||
transitionToPage(pageNum: pendingTransitionRequest.pageNum, animated: pendingTransitionRequest.animated)
|
||
}
|
||
|
||
// MARK: - Preload / Forecast
|
||
|
||
/// 确保预加载宿主视图已添加到视图层级
|
||
/// 该视图隐藏且不可交互，仅用于存放预加载的页面内容
|
||
private func ensurePreloadHostView() {
|
||
guard preloadHostView.superview == nil else { return }
|
||
preloadHostView.isHidden = true
|
||
preloadHostView.isUserInteractionEnabled = false
|
||
preloadHostView.clipsToBounds = true
|
||
preloadHostView.frame = bounds
|
||
preloadHostView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
|
||
insertSubview(preloadHostView, at: 0)
|
||
}
|
||
|
||
/// 判断指定页码是否可以被缓存
|
||
/// - Parameter pageNum: 页码
|
||
/// - Returns: true 表示可以缓存（有效页码且在范围内）
|
||
private func shouldCachePage(_ pageNum: Int) -> Bool {
|
||
pageNum >= 0
|
||
&& pageNum != RDReaderView.blankPageNum
|
||
&& pageNum != RDReaderView.blankEndPageNum
|
||
&& pageNum < (dataSource?.pageCountOfReaderView(readerView: self) ?? 0)
|
||
}
|
||
|
||
/// 获取当前缓存签名，用于检测布局环境是否发生变化
|
||
private func currentCacheSignature() -> CacheSignature {
|
||
CacheSignature(
|
||
displayType: currentDisplayType,
|
||
isLandscape: isLandscape,
|
||
pagesPerScreen: pagesPerScreen,
|
||
boundsSize: bounds.size
|
||
)
|
||
}
|
||
|
||
/// 清空所有页面缓存并更新缓存签名
|
||
/// 在翻页模式切换、横竖屏切换时调用
|
||
private func invalidatePageCaches() {
|
||
pageCurlCachedViews.values.forEach { $0.removeFromSuperview() }
|
||
preloadedPageViews.values.forEach { $0.removeFromSuperview() }
|
||
pageCurlCachedViews.removeAll()
|
||
preloadedPageViews.removeAll()
|
||
cacheSignature = currentCacheSignature()
|
||
}
|
||
|
||
/// 检查缓存签名是否变化，变化则清空缓存
|
||
private func refreshCacheSignatureIfNeeded() {
|
||
let signature = currentCacheSignature()
|
||
if cacheSignature != signature {
|
||
invalidatePageCaches()
|
||
} else if cacheSignature == nil {
|
||
cacheSignature = signature
|
||
}
|
||
}
|
||
|
||
/// 计算指定页码所在"展开对"的起始页码
|
||
/// 单页模式返回自身，双页模式返回配对的左页码
|
||
private func spreadStart(for pageNum: Int) -> Int? {
|
||
guard shouldCachePage(pageNum) else { return nil }
|
||
let isDualPage = landscapeDualPageEnabled && isLandscape && currentDisplayType != .verticalScroll
|
||
guard isDualPage else { return pageNum }
|
||
return dualPagePair(for: pageNum).left
|
||
}
|
||
|
||
/// 获取指定页码所在"展开对"的所有页码
|
||
/// 单页模式返回自身，双页模式返回左右两页
|
||
private func spreadPageNumbers(startingAt pageNum: Int) -> Set<Int> {
|
||
guard shouldCachePage(pageNum) else { return [] }
|
||
let isDualPage = landscapeDualPageEnabled && isLandscape && currentDisplayType != .verticalScroll
|
||
guard isDualPage else { return [pageNum] }
|
||
let pair = dualPagePair(for: pageNum)
|
||
var pages: Set<Int> = [pair.left]
|
||
if let right = pair.right, shouldCachePage(right) {
|
||
pages.insert(right)
|
||
}
|
||
return pages
|
||
}
|
||
|
||
/// 计算相邻"展开对"的起始页码，用于预加载时计算前后相邻页
|
||
private func adjacentSpreadStart(from pageNum: Int, forward: Bool) -> Int? {
|
||
let totalPages = dataSource?.pageCountOfReaderView(readerView: self) ?? 0
|
||
guard totalPages > 0,
|
||
let spreadStart = spreadStart(for: pageNum) else {
|
||
return nil
|
||
}
|
||
|
||
let isDualPage = landscapeDualPageEnabled && isLandscape && currentDisplayType != .verticalScroll
|
||
guard isDualPage else {
|
||
let target = forward ? spreadStart + 1 : spreadStart - 1
|
||
return shouldCachePage(target) ? target : nil
|
||
}
|
||
|
||
if forward {
|
||
return adjacentDualPage(from: spreadStart, forward: true)
|
||
}
|
||
|
||
let pair = dualPagePair(for: spreadStart)
|
||
let prevEnd = pair.left - 1
|
||
guard prevEnd >= 0 else { return nil }
|
||
return dualPagePair(for: prevEnd).left
|
||
}
|
||
|
||
/// 获取锚定页码对应的可见页码集合
|
||
private func visiblePageNumbers(for anchorPage: Int) -> Set<Int> {
|
||
spreadPageNumbers(startingAt: anchorPage)
|
||
}
|
||
|
||
/// 获取用于显示的页面视图
|
||
/// 优先从缓存中获取，其次从预加载缓存中获取，最后新建
|
||
private func pageViewForDisplay(pageNum: Int) -> UIView {
|
||
if let cached = pageCurlCachedViews[pageNum] {
|
||
return cached
|
||
}
|
||
if let preloaded = preloadedPageViews.removeValue(forKey: pageNum) {
|
||
preloaded.removeFromSuperview()
|
||
pageCurlCachedViews[pageNum] = preloaded
|
||
return preloaded
|
||
}
|
||
let view = dataSource?.pageContentView(readerView: self, pageNum: pageNum, containerView: nil) ?? UIView()
|
||
pageCurlCachedViews[pageNum] = view
|
||
return view
|
||
}
|
||
|
||
/// 裁剪缓存，只保留指定页码集合中的页面
|
||
/// 不在保留集合中的页面会被从视图层级中移除
|
||
private func trimCachedPageViews(keeping pageNumbers: Set<Int>) {
|
||
pageCurlCachedViews = pageCurlCachedViews.filter { key, value in
|
||
let keep = pageNumbers.contains(key)
|
||
if !keep {
|
||
value.removeFromSuperview()
|
||
}
|
||
return keep
|
||
}
|
||
|
||
preloadedPageViews = preloadedPageViews.filter { key, value in
|
||
let keep = pageNumbers.contains(key)
|
||
if !keep {
|
||
value.removeFromSuperview()
|
||
}
|
||
return keep
|
||
}
|
||
}
|
||
|
||
/// 预测需要预加载的页码集合
|
||
/// 基于当前页码和 preloadRadius，向前和向后各预测 preloadRadius 屏，
|
||
/// 并根据 preferredForward 方向额外多预测一屏
|
||
private func forecastTargets(around pageNum: Int, preferredForward: Bool?) -> [Int] {
|
||
let totalPages = dataSource?.pageCountOfReaderView(readerView: self) ?? 0
|
||
guard totalPages > 0, shouldCachePage(pageNum) else { return [] }
|
||
|
||
var targets = Set<Int>()
|
||
|
||
var previousAnchor = pageNum
|
||
for _ in 0..<max(preloadRadius, 0) {
|
||
guard let prev = adjacentSpreadStart(from: previousAnchor, forward: false) else { break }
|
||
targets.formUnion(spreadPageNumbers(startingAt: prev))
|
||
previousAnchor = prev
|
||
}
|
||
|
||
var nextAnchor = pageNum
|
||
for _ in 0..<max(preloadRadius, 0) {
|
||
guard let next = adjacentSpreadStart(from: nextAnchor, forward: true) else { break }
|
||
targets.formUnion(spreadPageNumbers(startingAt: next))
|
||
nextAnchor = next
|
||
}
|
||
|
||
if let preferredForward,
|
||
let edgeAnchor = preferredForward ? adjacentSpreadStart(from: nextAnchor, forward: true)
|
||
: adjacentSpreadStart(from: previousAnchor, forward: false) {
|
||
targets.formUnion(spreadPageNumbers(startingAt: edgeAnchor))
|
||
}
|
||
|
||
return targets.sorted()
|
||
}
|
||
|
||
/// 预加载核心方法
|
||
/// 1. 检查缓存签名是否需要更新
|
||
/// 2. 预测需要预加载的页码
|
||
/// 3. 裁剪不在范围内的缓存
|
||
/// 4. 创建或复用预加载视图
|
||
private func primePageCache(around pageNum: Int, preferredForward: Bool? = nil) {
|
||
refreshCacheSignatureIfNeeded()
|
||
let targets = forecastTargets(around: pageNum, preferredForward: preferredForward)
|
||
let keepSet = Set(targets).union(visiblePageNumbers(for: pageNum))
|
||
trimCachedPageViews(keeping: keepSet)
|
||
guard !targets.isEmpty else { return }
|
||
|
||
ensurePreloadHostView()
|
||
preloadHostView.frame = bounds
|
||
|
||
for targetPage in targets {
|
||
let existing = preloadedPageViews[targetPage] ?? pageCurlCachedViews.removeValue(forKey: targetPage)
|
||
let contentView = dataSource?.pageContentView(readerView: self, pageNum: targetPage, containerView: existing) ?? existing ?? UIView()
|
||
preloadedPageViews[targetPage] = contentView
|
||
if contentView.superview !== preloadHostView {
|
||
contentView.removeFromSuperview()
|
||
preloadHostView.addSubview(contentView)
|
||
}
|
||
contentView.frame = preloadHostView.bounds
|
||
}
|
||
}
|
||
|
||
/// 视图被添加到父视图时调用，触发 UI 构建
|
||
public override func didMoveToSuperview() {
|
||
super.didMoveToSuperview()
|
||
|
||
if superview != nil {
|
||
makeUI()
|
||
}
|
||
}
|
||
|
||
/// 将 pageViewController 添加到父控制器和视图层级
|
||
/// 如果已在父控制器中则跳过，确保生命周期方法正确调用
|
||
private func attachPageViewControllerIfNeeded() {
|
||
guard let parentViewController = self.ss_superViewController else { return }
|
||
|
||
var didAddToParent = false
|
||
if pageViewController.parent !== parentViewController {
|
||
if pageViewController.parent != nil {
|
||
pageViewController.willMove(toParent: nil)
|
||
pageViewController.view.removeFromSuperview()
|
||
pageViewController.removeFromParent()
|
||
}
|
||
parentViewController.addChild(pageViewController)
|
||
didAddToParent = true
|
||
}
|
||
|
||
pageViewController.view.frame = CGRect(x: 0, y: 0, width: frame.width, height: frame.height)
|
||
pageViewController.view.autoresizingMask = [.flexibleWidth, .flexibleHeight]
|
||
if pageViewController.view.superview !== self {
|
||
insertSubview(pageViewController.view, at: 0)
|
||
}
|
||
|
||
if didAddToParent {
|
||
pageViewController.didMove(toParent: parentViewController)
|
||
}
|
||
|
||
if currentDisplayType == .pageCurl, !isTransitioning, pendingTransitionRequest != nil {
|
||
finishPageCurlTransition(repairFaultIfNeeded: false)
|
||
}
|
||
}
|
||
|
||
/// 从父控制器和视图层级中移除 pageViewController
|
||
/// 确保 willMove/didMove 生命周期方法正确调用
|
||
private func detachPageViewControllerIfNeeded() {
|
||
if pageViewController.parent != nil {
|
||
pageViewController.willMove(toParent: nil)
|
||
}
|
||
pageViewController.view.removeFromSuperview()
|
||
if pageViewController.parent != nil {
|
||
pageViewController.removeFromParent()
|
||
}
|
||
}
|
||
|
||
/// 构建 UI 界面
|
||
/// 首次调用时注册 cell、添加手势识别器、根据当前翻页模式添加对应视图
|
||
private func makeUI() {
|
||
guard !didBuildUI else {
|
||
if currentDisplayType == .pageCurl {
|
||
attachPageViewControllerIfNeeded()
|
||
}
|
||
return
|
||
}
|
||
didBuildUI = true
|
||
|
||
collectionView.dataSource = self
|
||
collectionView.register(UICollectionViewCell.self, forCellWithReuseIdentifier: NSStringFromClass(UICollectionViewCell.self))
|
||
collectionView.frame = CGRect(x: 0, y: 0, width: frame.width, height: frame.height)
|
||
collectionView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
|
||
|
||
if currentDisplayType == .pageCurl {
|
||
attachPageViewControllerIfNeeded()
|
||
}
|
||
ensurePreloadHostView()
|
||
cacheSignature = currentCacheSignature()
|
||
|
||
addGestureRecognizer(tapGestureRecognizer)
|
||
// 不取消底层触摸事件，确保工具栏按钮（返回等）的 touchUpInside 能正常触发
|
||
tapGestureRecognizer.cancelsTouchesInView = false
|
||
|
||
}
|
||
|
||
/// 点击手势响应方法
|
||
/// 根据点击位置将屏幕三等分，判断点击区域并设置 tapEvent
|
||
@objc private func tapAction(tap: UITapGestureRecognizer) {
|
||
let point = tap.location(in: tap.view)
|
||
if isShowToolView {
|
||
let hitView = hitTest(point, with: nil)
|
||
if let top = topToolView, isHitView(hitView, inside: top, point: point) { return }
|
||
if let bottom = bottomToolView, isHitView(hitView, inside: bottom, point: point) { return }
|
||
}
|
||
let viewFrame = tap.view!.frame
|
||
let leftFrame = CGRect(x: 0, y: 0, width: viewFrame.width / 3, height: viewFrame.height)
|
||
let centerFrame = CGRect(x: viewFrame.width / 3, y: 0, width: viewFrame.width / 3, height: viewFrame.height)
|
||
let rightFrame = CGRect(x: viewFrame.width * 2 / 3, y: 0, width: viewFrame.width / 3, height: viewFrame.height)
|
||
if leftFrame.contains(point) {
|
||
if isShowToolView {
|
||
tapEvent = .center
|
||
} else {
|
||
tapEvent = .left
|
||
}
|
||
}
|
||
|
||
if centerFrame.contains(point) {
|
||
tapEvent = .center
|
||
}
|
||
|
||
if rightFrame.contains(point) {
|
||
if isShowToolView {
|
||
tapEvent = .center
|
||
} else {
|
||
tapEvent = .right
|
||
}
|
||
}
|
||
}
|
||
|
||
/// 点击屏幕中央区域，切换工具栏的显示/隐藏
|
||
/// 显示时：工具栏从屏幕外滑入，禁用翻页交互
|
||
/// 隐藏时：工具栏滑出屏幕，恢复翻页交互
|
||
private func tapCenter() {
|
||
isShowToolView = !isShowToolView
|
||
if isShowToolView {
|
||
if let topToolView = topToolView {
|
||
addSubview(topToolView)
|
||
topToolView.translatesAutoresizingMaskIntoConstraints = false
|
||
NSLayoutConstraint.activate([
|
||
topToolView.leadingAnchor.constraint(equalTo: leadingAnchor),
|
||
topToolView.trailingAnchor.constraint(equalTo: trailingAnchor),
|
||
topToolView.topAnchor.constraint(equalTo: topAnchor)
|
||
])
|
||
layoutIfNeeded()
|
||
topToolView.transform = CGAffineTransform(translationX: 0, y: -topToolView.bounds.height)
|
||
UIView.animate(withDuration: toolViewAnimationDuration) {
|
||
topToolView.transform = .identity
|
||
}
|
||
}
|
||
|
||
if let bottomToolView = bottomToolView {
|
||
addSubview(bottomToolView)
|
||
bottomToolView.translatesAutoresizingMaskIntoConstraints = false
|
||
NSLayoutConstraint.activate([
|
||
bottomToolView.leadingAnchor.constraint(equalTo: leadingAnchor),
|
||
bottomToolView.trailingAnchor.constraint(equalTo: trailingAnchor),
|
||
bottomToolView.bottomAnchor.constraint(equalTo: bottomAnchor)
|
||
])
|
||
layoutIfNeeded()
|
||
bottomToolView.transform = CGAffineTransform(translationX: 0, y: bottomToolView.bounds.height)
|
||
UIView.animate(withDuration: toolViewAnimationDuration) {
|
||
bottomToolView.transform = .identity
|
||
}
|
||
}
|
||
|
||
collectionView.isUserInteractionEnabled = false
|
||
pageViewController.view.isUserInteractionEnabled = false
|
||
} else {
|
||
if let topToolView = topToolView {
|
||
UIView.animate(withDuration: toolViewAnimationDuration, animations: {
|
||
topToolView.transform = CGAffineTransform(translationX: 0, y: -topToolView.bounds.height)
|
||
}) { _ in
|
||
topToolView.removeFromSuperview()
|
||
}
|
||
}
|
||
|
||
if let bottomToolView = bottomToolView {
|
||
UIView.animate(withDuration: toolViewAnimationDuration, animations: {
|
||
bottomToolView.transform = CGAffineTransform(translationX: 0, y: bottomToolView.bounds.height)
|
||
}) { _ in
|
||
bottomToolView.removeFromSuperview()
|
||
}
|
||
}
|
||
|
||
collectionView.isUserInteractionEnabled = true
|
||
pageViewController.view.isUserInteractionEnabled = true
|
||
}
|
||
}
|
||
|
||
/// 判断点击命中的视图是否在指定工具栏内
|
||
private func isHitView(_ hitView: UIView?, inside toolView: UIView, point: CGPoint) -> Bool {
|
||
if toolView.frame.contains(point) {
|
||
return true
|
||
}
|
||
|
||
guard let hitView else { return false }
|
||
return hitView === toolView || hitView.isDescendant(of: toolView)
|
||
}
|
||
|
||
/// 切换翻页模式（仿真/水平滚动/上下滚动）
|
||
/// 会重建底层视图（PageViewController 或 CollectionView），并恢复到当前页
|
||
/// - Parameter displayType: 目标翻页模式
|
||
public func switchReaderDisplayType(_ displayType: RDReaderView.DisplayType) {
|
||
let previousDisplayType = currentDisplayType
|
||
self.currentDisplayType = displayType
|
||
if currentPage == -1 {
|
||
currentPage = 0
|
||
}
|
||
if previousDisplayType != displayType {
|
||
invalidatePageCaches()
|
||
}
|
||
// 同步横屏双页标记到布局
|
||
layout.isLandscapeDualPage = landscapeDualPageEnabled && isLandscape
|
||
layout.coverPageIndex = coverPageIndex
|
||
switch displayType {
|
||
case .pageCurl:
|
||
self.collectionView.removeFromSuperview()
|
||
self.collectionView.transform = .identity
|
||
attachPageViewControllerIfNeeded()
|
||
rebuildPageViewController()
|
||
transitionToPage(pageNum: currentPage)
|
||
primePageCache(around: currentPage, preferredForward: predictedPageDirection)
|
||
default:
|
||
detachPageViewControllerIfNeeded()
|
||
// RTL 水平模式翻转 collectionView
|
||
if pageDirection == .rightToLeft && displayType != .verticalScroll {
|
||
collectionView.transform = CGAffineTransform(scaleX: -1, y: 1)
|
||
} else {
|
||
collectionView.transform = .identity
|
||
}
|
||
// 确保 collectionView frame 正确后再触发布局计算
|
||
collectionView.frame = CGRect(x: 0, y: 0, width: frame.width, height: frame.height)
|
||
insertSubview(self.collectionView, at: 0)
|
||
layout.displayType = displayType
|
||
transitionToPage(pageNum: currentPage)
|
||
primePageCache(around: currentPage, preferredForward: predictedPageDirection)
|
||
}
|
||
}
|
||
|
||
/// 跳转到指定页码
|
||
/// 支持所有翻页模式：
|
||
/// - pageCurl：通过 UIPageViewController.setViewControllers 实现
|
||
/// - 滚动模式：通过 setContentOffset 实现
|
||
/// - Parameters:
|
||
/// - pageNum: 目标页码（item 索引）
|
||
/// - animated: 是否动画过渡
|
||
public func transitionToPage(pageNum: Int, animated: Bool = false) {
|
||
guard let safePageNum = clampedPageNumber(pageNum) else { return }
|
||
switch currentDisplayType {
|
||
case .pageCurl:
|
||
let request = PageTransitionRequest(pageNum: safePageNum, animated: animated)
|
||
if shouldQueuePageTransition(request) {
|
||
return
|
||
}
|
||
|
||
let isDualPage = landscapeDualPageEnabled && isLandscape
|
||
// RTL 时动画方向需要反转
|
||
let direction: UIPageViewController.NavigationDirection
|
||
if pageDirection == .rightToLeft {
|
||
direction = safePageNum > currentPage ? .reverse : .forward
|
||
} else {
|
||
direction = safePageNum > currentPage ? .forward : .reverse
|
||
}
|
||
predictedPageDirection = currentPage >= 0 ? safePageNum >= currentPage : nil
|
||
attachPageViewControllerIfNeeded()
|
||
if isDualPage {
|
||
let pair = dualPagePair(for: safePageNum)
|
||
let leftContent = pageViewForDisplay(pageNum: pair.left)
|
||
let leftVC = RDReaderPageChildViewController(contentView: leftContent, pageNum: pair.left)
|
||
isTransitioning = animated
|
||
if let rightPage = pair.right {
|
||
let rightContent = pageViewForDisplay(pageNum: rightPage)
|
||
let rightVC = RDReaderPageChildViewController(contentView: rightContent, pageNum: rightPage)
|
||
pageViewController.setViewControllers([leftVC, rightVC], direction: animated ? direction : .forward, animated: animated) { [weak self] _ in
|
||
guard let self else { return }
|
||
self.finishPageCurlTransition()
|
||
}
|
||
} else {
|
||
// 封面页独占或奇数最后一页：右侧放空白页
|
||
let blankNum = isFullScreenPage(pair.left) ? RDReaderView.blankPageNum : RDReaderView.blankEndPageNum
|
||
let emptyVC = RDReaderPageChildViewController(contentView: UIView(), pageNum: blankNum)
|
||
pageViewController.setViewControllers([leftVC, emptyVC], direction: animated ? direction : .forward, animated: animated) { [weak self] _ in
|
||
guard let self else { return }
|
||
self.finishPageCurlTransition()
|
||
}
|
||
}
|
||
currentPage = pair.left
|
||
primePageCache(around: pair.left, preferredForward: predictedPageDirection)
|
||
} else {
|
||
let contentView = pageViewForDisplay(pageNum: safePageNum)
|
||
let vc = RDReaderPageChildViewController(contentView: contentView, pageNum: safePageNum)
|
||
isTransitioning = animated
|
||
pageViewController.setViewControllers([vc], direction: animated ? direction : .forward, animated: animated) { [weak self] _ in
|
||
guard let self else { return }
|
||
self.finishPageCurlTransition()
|
||
}
|
||
currentPage = safePageNum
|
||
primePageCache(around: safePageNum, preferredForward: predictedPageDirection)
|
||
}
|
||
default:
|
||
collectionView.reloadData()
|
||
collectionView.layoutIfNeeded()
|
||
predictedPageDirection = currentPage >= 0 ? safePageNum >= currentPage : nil
|
||
collectionView.setContentOffset(layout.currentContentOffset(count: safePageNum), animated: animated)
|
||
currentPage = safePageNum
|
||
primePageCache(around: safePageNum, preferredForward: predictedPageDirection)
|
||
}
|
||
}
|
||
|
||
/// 重新加载数据
|
||
/// 重新切换到当前翻页模式，并刷新工具栏
|
||
public func reloadData() {
|
||
switchReaderDisplayType(currentDisplayType)
|
||
topToolView = self.dataSource?.topToolView?(readerView: self)
|
||
bottomToolView = self.dataSource?.bottomToolView?(readerView: self)
|
||
}
|
||
|
||
|
||
required init?(coder: NSCoder) {
|
||
fatalError("init(coder:) has not been implemented")
|
||
}
|
||
|
||
}
|
||
|
||
|
||
|
||
/// UIPageViewController 数据源和代理实现
|
||
/// 处理仿真翻页模式下的页面数据供给和翻页事件
|
||
extension RDReaderView: UIPageViewControllerDataSource, UIPageViewControllerDelegate {
|
||
|
||
/// 创建指定页码的子控制器
|
||
/// 空白页返回空视图，正常页从缓存或数据源获取内容
|
||
private func makeSinglePageChildVC(for pageNum: Int) -> RDReaderPageChildViewController {
|
||
if pageNum == RDReaderView.blankPageNum || pageNum == RDReaderView.blankEndPageNum {
|
||
return RDReaderPageChildViewController(contentView: UIView(), pageNum: pageNum)
|
||
}
|
||
let contentView = pageViewForDisplay(pageNum: pageNum)
|
||
return RDReaderPageChildViewController(contentView: contentView, pageNum: pageNum)
|
||
}
|
||
|
||
/// 计算某页的"下一页"页码
|
||
/// 考虑封面页独占和末尾空白页配对的情况
|
||
/// - Parameters:
|
||
/// - pageNum: 当前页码
|
||
/// - isDualPage: 是否双页模式
|
||
/// - Returns: 下一页页码，nil 表示没有下一页
|
||
private func nextPageNum(after pageNum: Int, isDualPage: Bool) -> Int? {
|
||
let totalPages = dataSource?.pageCountOfReaderView(readerView: self) ?? 0
|
||
|
||
// 末尾空白页之后没有更多页
|
||
if pageNum == RDReaderView.blankEndPageNum {
|
||
return nil
|
||
}
|
||
|
||
if isDualPage, let coverIndex = coverPageIndex {
|
||
if pageNum == coverIndex {
|
||
return RDReaderView.blankPageNum
|
||
}
|
||
if pageNum == RDReaderView.blankPageNum {
|
||
let firstContent = coverIndex + 1
|
||
return firstContent < totalPages ? firstContent : nil
|
||
}
|
||
}
|
||
|
||
let next = pageNum + 1
|
||
if next < totalPages {
|
||
return next
|
||
}
|
||
|
||
// pageNum 是最后一页，检查在双页模式下是否需要空白页配对
|
||
if isDualPage {
|
||
if let coverIndex = coverPageIndex {
|
||
// 有封面时：封面之后的页面两两配对，偶数偏移=左页需要配对
|
||
let adjustedIndex = pageNum - (coverIndex + 1)
|
||
if adjustedIndex >= 0 && adjustedIndex % 2 == 0 {
|
||
return RDReaderView.blankEndPageNum
|
||
}
|
||
} else {
|
||
// 无封面：偶数索引=左页需要配对
|
||
if pageNum % 2 == 0 {
|
||
return RDReaderView.blankEndPageNum
|
||
}
|
||
}
|
||
}
|
||
return nil
|
||
}
|
||
|
||
/// 计算某页的"上一页"页码
|
||
/// 考虑封面页独占和末尾空白页配对的情况
|
||
/// - Parameters:
|
||
/// - pageNum: 当前页码
|
||
/// - isDualPage: 是否双页模式
|
||
/// - Returns: 上一页页码，nil 表示没有上一页
|
||
private func prevPageNum(before pageNum: Int, isDualPage: Bool) -> Int? {
|
||
// 末尾空白页的前一页是最后一个真实页
|
||
if pageNum == RDReaderView.blankEndPageNum {
|
||
let totalPages = dataSource?.pageCountOfReaderView(readerView: self) ?? 0
|
||
return totalPages > 0 ? totalPages - 1 : nil
|
||
}
|
||
if isDualPage, let coverIndex = coverPageIndex {
|
||
if pageNum == RDReaderView.blankPageNum {
|
||
return coverIndex
|
||
}
|
||
if pageNum == coverIndex + 1 {
|
||
return RDReaderView.blankPageNum
|
||
}
|
||
}
|
||
let prev = pageNum - 1
|
||
return prev >= 0 ? prev : nil
|
||
}
|
||
|
||
/// UIPageViewController 数据源：返回当前页之前（左/上）的页面控制器
|
||
/// RTL 模式下 before/after 语义互换：before（向右翻）= 下一页
|
||
public func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
|
||
guard let vc = viewController as? RDReaderPageChildViewController else { return nil }
|
||
let isDualPage = landscapeDualPageEnabled && isLandscape
|
||
let isRTL = pageDirection == .rightToLeft
|
||
|
||
// RTL 时 before/after 语义互换：before（向右翻）= 下一页
|
||
let targetNum = isRTL
|
||
? nextPageNum(after: vc.pageNum, isDualPage: isDualPage)
|
||
: prevPageNum(before: vc.pageNum, isDualPage: isDualPage)
|
||
|
||
guard let num = targetNum else { return nil }
|
||
let targetVC = makeSinglePageChildVC(for: num)
|
||
willPreviousTransitionToViewController = targetVC
|
||
return targetVC
|
||
}
|
||
|
||
/// UIPageViewController 数据源：返回当前页之后（右/下）的页面控制器
|
||
/// RTL 模式下 before/after 语义互换
|
||
public func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
|
||
guard let vc = viewController as? RDReaderPageChildViewController else { return nil }
|
||
let isDualPage = landscapeDualPageEnabled && isLandscape
|
||
let isRTL = pageDirection == .rightToLeft
|
||
|
||
let targetNum = isRTL
|
||
? prevPageNum(before: vc.pageNum, isDualPage: isDualPage)
|
||
: nextPageNum(after: vc.pageNum, isDualPage: isDualPage)
|
||
|
||
guard let num = targetNum else { return nil }
|
||
let targetVC = makeSinglePageChildVC(for: num)
|
||
willNextTransitionToViewController = targetVC
|
||
return targetVC
|
||
}
|
||
|
||
/// UIPageViewController 代理：翻页动画完成回调
|
||
/// 更新当前页码，触发预加载，并检测 PageViewController 异常状态
|
||
public func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
|
||
if completed, let firstVC = pageViewController.viewControllers?.first as? RDReaderPageChildViewController {
|
||
let pn = firstVC.pageNum
|
||
if pn != RDReaderView.blankPageNum && pn != RDReaderView.blankEndPageNum {
|
||
currentPage = pn
|
||
primePageCache(around: pn, preferredForward: predictedPageDirection)
|
||
}
|
||
}
|
||
|
||
predictedPageDirection = nil
|
||
finishPageCurlTransition()
|
||
}
|
||
|
||
/// UIPageViewController 代理：即将开始转场动画
|
||
/// 记录预测的翻页方向，用于优化预加载策略
|
||
public func pageViewController(_ pageViewController: UIPageViewController, willTransitionTo pendingViewControllers: [UIViewController]) {
|
||
isTransitioning = true
|
||
willTransitionToViewController = pendingViewControllers.first
|
||
if let target = pendingViewControllers.first as? RDReaderPageChildViewController,
|
||
target.pageNum != RDReaderView.blankPageNum,
|
||
target.pageNum != RDReaderView.blankEndPageNum {
|
||
predictedPageDirection = target.pageNum >= currentPage
|
||
primePageCache(around: target.pageNum, preferredForward: predictedPageDirection)
|
||
}
|
||
}
|
||
|
||
}
|
||
|
||
/// UICollectionView 数据源和自定义布局代理实现
|
||
/// 处理水平滚动和垂直滚动两种翻页模式
|
||
extension RDReaderView: UICollectionViewDataSource, RDReaderFlowLayoutDelegate, RDReaderFlowLayoutDataSoure {
|
||
/// 配置 UICollectionViewCell
|
||
/// 通过 DataSource 获取页面内容视图，支持 cell 复用和预加载视图复用
|
||
/// RTL 水平模式下翻转 cell 内容使文字方向正常
|
||
public func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
|
||
|
||
|
||
if let identifer = self.dataSource?.pageIdentifier(readerView: self, pageNum: indexPath.row) {
|
||
|
||
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: identifer, for: IndexPath(item: indexPath.row, section: 0)) as! RDReaderContentCell
|
||
let preloadedView = preloadedPageViews.removeValue(forKey: indexPath.row)
|
||
preloadedView?.removeFromSuperview()
|
||
let reusableView = cell.containerView ?? preloadedView
|
||
let conttainerView = self.dataSource?.pageContentView(readerView: self, pageNum: indexPath.row, containerView: reusableView)
|
||
if let conttainerView = conttainerView {
|
||
cell.containerView = conttainerView
|
||
}
|
||
// RTL 水平模式：翻转 cell 内容使文字方向正常（collectionView 已整体翻转）
|
||
if pageDirection == .rightToLeft && currentDisplayType != .verticalScroll {
|
||
cell.contentView.transform = CGAffineTransform(scaleX: -1, y: 1)
|
||
} else {
|
||
cell.contentView.transform = .identity
|
||
}
|
||
return cell
|
||
}
|
||
|
||
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: NSStringFromClass(UICollectionViewCell.self), for: indexPath)
|
||
|
||
return cell
|
||
}
|
||
|
||
/// 返回每组的 item 数量，即总页数
|
||
public func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
|
||
return self.dataSource?.pageCountOfReaderView(readerView: self) ?? 0
|
||
}
|
||
|
||
/// 布局代理回调：当前可见页码变化时通知
|
||
public func pageNum(flowLayout: RDReaderFlowLayout, pageIndex: Int) {
|
||
if currentPage >= 0, currentPage != pageIndex {
|
||
predictedPageDirection = pageIndex >= currentPage
|
||
}
|
||
currentPage = pageIndex
|
||
primePageCache(around: pageIndex, preferredForward: predictedPageDirection)
|
||
}
|
||
|
||
/// 布局数据源回调：返回垂直滚动模式下指定页的高度
|
||
/// 当前返回 nil 使用默认高度
|
||
public func heigtOfVerticalScrollPage(flowLayout: RDReaderFlowLayout, pageIndex: Int) -> CGFloat? {
|
||
return nil
|
||
}
|
||
}
|
||
|
||
/// 内容视图注册和复用扩展
|
||
/// 提供类似 UITableView 的 register/dequeueReusable 机制
|
||
extension RDReaderView {
|
||
/// 注册内容视图类型
|
||
/// - Parameters:
|
||
/// - contentView: 内容视图的类型
|
||
/// - identifier: 重用标识符
|
||
public func register(contentView: UIView.Type, contentViewWithReuseIdentifier identifier: String) {
|
||
contentViews[identifier] = contentView
|
||
collectionView.register(RDReaderContentCell.self, forCellWithReuseIdentifier: identifier)
|
||
}
|
||
|
||
/// 获取可复用的内容视图
|
||
/// 优先从当前显示的 cell 中获取，其次创建新实例
|
||
public func dequeueReusableContentView(withReuseIdentifier identifier: String, for pageNum: Int) -> UIView {
|
||
if self.currentDisplayType != .pageCurl, let cell = self.collectionView.cellForItem(at: IndexPath(row: pageNum, section: 0)) as? RDReaderContentCell, let containerView = cell.containerView {
|
||
return containerView
|
||
}
|
||
let contentViewClass = contentViews[identifier]
|
||
assert(contentViewClass != nil, "请调用register(contentView：contentViewWithReuseIdentifier：）")
|
||
var contentView = contentViewClass!.init()
|
||
return contentView
|
||
}
|
||
|
||
/// 获取指定页码的内容视图
|
||
/// pageCurl 模式从 PageViewController 获取，滚动模式从 CollectionView cell 获取
|
||
public func pageContentView(pageNum: Int) -> UIView? {
|
||
if currentDisplayType == .pageCurl {
|
||
return (self.pageViewController.viewControllers?.first as? RDReaderPageChildViewController)?.contentView
|
||
} else {
|
||
let cell = collectionView.cellForItem(at: IndexPath(item: pageNum, section: 0)) as? RDReaderContentCell
|
||
return cell?.containerView
|
||
}
|
||
}
|
||
|
||
/// 返回当前阅读模式下单页内容容器的实际尺寸。
|
||
/// 优先使用已经显示出来的内容视图尺寸；若页面尚未装载，则回退到当前模式下的理论单页尺寸。
|
||
public func resolvedSinglePageSize(pageNum: Int? = nil) -> CGSize {
|
||
let targetPage = pageNum ?? (currentPage >= 0 ? currentPage : nil)
|
||
if let targetPage,
|
||
let contentView = pageContentView(pageNum: targetPage),
|
||
contentView.bounds.width > 0,
|
||
contentView.bounds.height > 0 {
|
||
return contentView.bounds.size
|
||
}
|
||
|
||
if currentDisplayType == .pageCurl {
|
||
if let childViewController = pageViewController.viewControllers?.first as? RDReaderPageChildViewController,
|
||
childViewController.view.bounds.width > 0,
|
||
childViewController.view.bounds.height > 0 {
|
||
return childViewController.view.bounds.size
|
||
}
|
||
if pageViewController.view.bounds.width > 0, pageViewController.view.bounds.height > 0 {
|
||
return pageViewController.view.bounds.size
|
||
}
|
||
return bounds.size
|
||
}
|
||
|
||
let containerBounds = collectionView.bounds.size == .zero ? bounds.size : collectionView.bounds.size
|
||
guard containerBounds.width > 0, containerBounds.height > 0 else {
|
||
return bounds.size
|
||
}
|
||
|
||
switch currentDisplayType {
|
||
case .horizontalScroll:
|
||
return CGSize(
|
||
width: containerBounds.width / CGFloat(max(pagesPerScreen, 1)),
|
||
height: containerBounds.height
|
||
)
|
||
case .verticalScroll:
|
||
return containerBounds
|
||
case .pageCurl:
|
||
return bounds.size
|
||
}
|
||
}
|
||
}
|
||
|
||
private var cellViewKey: Int8 = 0
|
||
|
||
/// UIView 扩展：通过响应链查找最近的父 UIViewController
|
||
extension UIView {
|
||
/// 沿响应链向上查找最近的 UIViewController
|
||
/// 用于在视图中获取其所在控制器的引用
|
||
var ss_superViewController: UIViewController? {
|
||
var next = self.next
|
||
while next != nil {
|
||
if next is UIViewController {
|
||
return next as? UIViewController
|
||
} else {
|
||
next = next!.next
|
||
}
|
||
}
|
||
return nil
|
||
}
|
||
|
||
}
|