Swift拆分小说阅读器功能，内部实现

　　公司项目结束了，公司估计也快黄了，年底事少，也给了我不少时间来维护博客。

　　公司的项目是一个类似于简书的创作平台，涵盖写作、小说、插画内容。

　　本期主要先下小说阅读部分，UI样式仿照的是微信读书样式，因之前也写过小说阅读器，但是代码并没有解耦，这次彻彻底底做一次大改动。

 　　小说用户的常见操作：当前阅读进入记录和书签列表，因公司项目的结构问题，目前新项目并没有做项目进度记录和书签保存功能，以后有优化时候，再补充相关内容。先看下小说的结构。

　　小说的主要模型ReadModel

　　小说章节模型

　　小说页面Model，一个页面，就是一个Model

　　一本书的数据结构确立后，进入功能开发

　　1、模型解析

　　1、把资源路径转化为正文，解析出所有的章节目录，把正文作为一个字符串，正则拆分出所有的章节，映射为ChapterModel

　　首先正则获取章节目录

1.  
   let content = path
2.  
   var models = Array<JFChapterModel>()
3.  
   var titles = Array<String>()
4.  
   DispatchQueue.global().async {
5.  
   let document = NSSearchPathForDirectoriesInDomains(FileManager.SearchPathDirectory.documentDirectory, FileManager.SearchPathDomainMask.userDomainMask, true).first
6.  
   let fileName = name
7.  
   let bookPath = document! "/\(String(fileName))"
8.  
   if FileManager.default.fileExists(atPath: bookPath) == false {
9.  
   try? FileManager.default.createDirectory(atPath: bookPath, withIntermediateDirectories: true, attributes: nil)
10.  
    }
11.  
     
12.  
    let results = self.doTitleMatchWith(content: content)
13.  
    if results.count == 0 {
14.  
    let model = JFChapterModel()
15.  
    model.chapterIndex = 1
16.  
    model.path = path
17.  
    completeHandler([], [model])
18.  
    }else {
19.  
    var endIndex = content.startIndex
20.  
     
21.  
    for (index, result) in results.enumerated() {
22.  
    let startIndex = content.index(content.startIndex, offsetBy: result.range.location)
23.  
    endIndex = content.index(startIndex, offsetBy: result.range.length)
24.  
     
25.  
    let currentTitle = String(content[startIndex...endIndex])
26.  
    titles.append(currentTitle)
27.  
    let chapterPath = bookPath "/chapter" String(index 1) ".txt"
28.  
    let model = JFChapterModel()
29.  
    model.chapterIndex = index 1
30.  
    model.title = currentTitle
31.  
    model.path = chapterPath
32.  
    models.append(model)
33.  
     
34.  
    if FileManager.default.fileExists(atPath: chapterPath) {
35.  
    continue
36.  
    }
37.  
    var endLoaction = 0
38.  
    if index == results.count - 1 {
39.  
    endLoaction = content.count - 1
40.  
    }else {
41.  
    endLoaction = results[index 1].range.location - 1
42.  
    }
43.  
    let startLocation = content.index(content.startIndex, offsetBy: result.range.location)
44.  
    let subString = String(content[startLocation...content.index(content.startIndex, offsetBy: endLoaction)])
45.  
    try! subString.write(toFile: chapterPath, atomically: true, encoding: String.Encoding.utf8)
46.  
     
47.  
    }
48.  
     
49.  
    DispatchQueue.main.async {
50.  
    completeHandler(titles, models)
51.  
    }
52.  
    }
53.  
    }

　　拿到阅读模型后，展示出来，就可以看书了。

　　2、翻页模式处理

　　翻页模式，有仿真、平移和滚动

　　这里以仿真为例子：

　　仿真的效果，使用 UIPageViewController

　　先添加 UIPageViewController 的视图，到阅读容器视图 contentView 上面

1.  
   private func loadPageViewController() -> Void {
2.  
    
3.  
   self.clearReaderViewIfNeed()
4.  
   let transtionStyle: UIPageViewController.TransitionStyle = (self.config.scrollType == .curl) ? .pageCurl : .scroll
5.  
   self.pageVC = JFContainerPageViewController(transitionStyle: transtionStyle, navigationOrientation: .horizontal, options: nil)
6.  
   self.pageVC?.dataSource = self
7.  
   self.pageVC?.delegate = self
8.  
   self.pageVC?.view.backgroundColor = UIColor.clear
9.  
    
10.  
    // 翻页背部带文字效果
11.  
    self.pageVC?.isDoubleSided = (self.config.scrollType == .curl) ? true : false
12.  
     
13.  
    self.addChild(self.pageVC!)
14.  
    self.view.addSubview((self.pageVC?.view)!)
15.  
    self.pageVC?.didMove(toParent: self)
16.  
    }

• 提供分页控制器的内容，即阅读内容

　　以下是获取下一页的代码，

　　获取上一页的，类似

1.  
   func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
2.  
   print("向后翻页 -------1")
3.  
   struct LastPage {
4.  
   static var arrived = false
5.  
   }
6.  
   let nextIndex: Int
7.  
   let pageArray = self.pageArrayFromCache(chapterIndex: currentChapterIndex)
8.  
   if viewController is JFPageViewController {
9.  
   let page = viewController as! DUAPageViewController
10.  
    nextIndex = page.index 1
11.  
    if nextIndex == pageArray.count {
12.  
    LastPage.arrived = true
13.  
    }
14.  
    let backPage = JFBackViewController()
15.  
    backPage.grabViewController(viewController: page)
16.  
    return backPage
17.  
    }
18.  
    if LastPage.arrived {
19.  
    LastPage.arrived = false
20.  
    if currentChapterIndex 1 > totalChapterModels.count {
21.  
    return nil
22.  
    }
23.  
    pageVC?.willStepIntoNextChapter = true
24.  
    self.requestChapterWith(index: currentChapterIndex 1)
25.  
    let nextPage = self.getPageVCWith(pageIndex: 0, chapterIndex: currentChapterIndex 1)
26.  
    /// 需要的页面并没有准备好，此时出现页面饥饿
27.  
    if nextPage == nil {
28.  
    self.postReaderStateNotification(state: .busy)
29.  
    pageHunger = true
30.  
    }
31.  
    return nextPage
32.  
    }
33.  
    let back = viewController as! JFBackViewController
34.  
    return self.getPageVCWith(pageIndex: back.index 1, chapterIndex: back.chapterBelong)
35.  
    }

　　3、计算页码

　　一个章节有几页，是怎么计算出来的？

　　先拿着一个章节的富文本，和显示区域，计算出书页的范围

　　通常显示区域，是放不满一章的。

　　显示区域先放一页，得到这一页的开始范围和长度，对应一个 ReadPageModel

　　显示区域再放下一页 ...

　　拿上一步计算出来的范围，创建该章节每一页的模型 ReadPageModel

1.  
   while rangeOffset <= attrString.length && rangeOffset != 0 {
2.  
   let pageModel = DUAPageModel.init()
3.  
   pageModel.attributedString = attrString.attributedSubstring(from: pageVisibleRange!)
4.  
   pageModel.range = pageVisibleRange
5.  
   pageModel.pageIndex = count - 1
6.  
    
7.  
   frame = layouter?.layoutFrame(with: rect, range: NSRange(location: rangeOffset, length: attrString.length - rangeOffset))
8.  
   pageVisibleRange = frame?.visibleStringRange()
9.  
   if pageVisibleRange == nil {
10.  
    rangeOffset = 0
11.  
    }else {
12.  
    rangeOffset = pageVisibleRange!.location pageVisibleRange!.length
13.  
    }
14.  
     
15.  
    let completed = (rangeOffset <= attrString.length && rangeOffset != 0) ? false : true
16.  
    completeHandler(count, pageModel, completed)
17.  
    count = 1
18.  
    }

　　4、翻页

　　获取下一页的代码

　　翻一页，就是当前的 RecordModel ， 翻到下一页，

　　交给阅读控制器去呈现， ReadViewController 的子类 ReadLongPressViewController

　　标准的模型更新，刷新视图

1.  
   func setViewController(viewController: UIViewController, direction: translationControllerNavigationDirection, animated: Bool, completionHandler: ((Bool) -> Void)?) -> Void {
2.  
   if animated == false {
3.  
   for controller in self.children {
4.  
   self.removeController(controller: controller)
5.  
   }
6.  
   self.addController(controller: viewController)
7.  
   if completionHandler != nil {
8.  
   completionHandler!(true)
9.  
   }
10.  
    }else {
11.  
    let oldController = self.children.first
12.  
    self.addController(controller: viewController)
13.  
     
14.  
    var newVCEndTransform: CGAffineTransform
15.  
    var oldVCEndTransform: CGAffineTransform
16.  
    viewController.view.transform = .identity
17.  
    if direction == .left {
18.  
    viewController.view.transform = CGAffineTransform(translationX: screenWidth, y: 0)
19.  
    newVCEndTransform = .identity
20.  
    oldController?.view.transform = .identity
21.  
    oldVCEndTransform = CGAffineTransform(translationX: -screenWidth, y: 0)
22.  
    }else {
23.  
    viewController.view.transform = CGAffineTransform(translationX: -screenWidth, y: 0)
24.  
    newVCEndTransform = .identity
25.  
    oldController?.view.transform = .identity
26.  
    oldVCEndTransform = CGAffineTransform(translationX: screenWidth, y: 0)
27.  
    }
28.  
     
29.  
    UIView.animate(withDuration: animationDuration, animations: {
30.  
    oldController?.view.transform = oldVCEndTransform
31.  
    viewController.view.transform = newVCEndTransform
32.  
    }, completion: { (complete) in
33.  
    if complete {
34.  
    self.removeController(controller: oldController!)
35.  
    }
36.  
    if completionHandler != nil {
37.  
    completionHandler!(complete)
38.  
    }
39.  
    })
40.  
    }
41.  
    }

　　//如果到了最后一章、最后一页时，就翻不动了

1.  
   self.postReaderStateNotification(state: .ready)
2.  
   if pageHunger {
3.  
   pageHunger = false
4.  
   if pageVC != nil {
5.  
   self.loadPage(pageIndex: currentPageIndex)
6.  
   }
7.  
   if tableView != nil {
8.  
   if currentPageIndex == 0 && tableView?.scrollDirection == .up {
9.  
   self.requestLastChapterForTableView()
10.  
    }
11.  
    if currentPageIndex == self.pageArrayFromCache(chapterIndex: currentChapterIndex).count - 1 && tableView?.scrollDirection == .down {
12.  
    self.requestNextChapterForTableView()
13.  
    }
14.  
    }
15.  
    }
16.  
     
17.  
    if firstIntoReader {
18.  
    firstIntoReader = false
19.  
    currentPageIndex = pageIndex <= 0 ? 0 : (pageIndex - 1)
20.  
    updateChapterIndex(index: chapter.chapterIndex)
21.  
    self.loadPage(pageIndex: currentPageIndex)
22.  
    if self.delegate?.reader(reader: readerProgressUpdated: curPage: totalPages: ) != nil {
23.  
    self.delegate?.reader(reader: self, readerProgressUpdated: currentChapterIndex, curPage: currentPageIndex 1, totalPages: self.pageArrayFromCache(chapterIndex: currentChapterIndex).count)
24.  
    }
25.  
    }
26.  
     
27.  
    if isReCutPage {
28.  
    isReCutPage = false
29.  
    var newIndex = 1
30.  
    for (index, item) in pages.enumerated() {
31.  
    if prePageStartLocation >= (item.range?.location)! && prePageStartLocation <= (item.range?.location)! (item.range?.length)! {
32.  
    newIndex = index
33.  
    }
34.  
    }
35.  
    currentPageIndex = newIndex
36.  
    self.loadPage(pageIndex: currentPageIndex)
37.  
     
38.  
    /// 触发预缓存
39.  
    // self.forwardCacheIfNeed(forward: true)
40.  
    // self.forwardCacheIfNeed(forward: false)
41.  
    }
42.  
     
43.  
    if successSwitchChapter != 0 {
44.  
    self.readChapterBy(index: successSwitchChapter, pageIndex: 1)
45.  
    }

 　　小说内容，实在太多，一时不知道下手开始写这边博文，就借鉴了别人的写作思路。地址：https://segmentfault.com/a/1190000023555795