优化

app/src/main/java/io/legado/app/model/localBook/EpubFile.kt

@@ -142,7 +142,7 @@ class EpubFile(var book: Book) {
             return "<img src=\"cover.jpeg\" />"
         }
         /*获取当前章节文本*/
-        epubBook?.let {
+        val contents = epubBookContents ?: return null
         val nextChapterFirstResourceHref = chapter.getVariable("nextUrl")?.substringBeforeLast("#")
         val currentChapterFirstResourceHref = chapter.url.substringBeforeLast("#")
         val isLastChapter = nextChapterFirstResourceHref.isNullOrBlank()
@@ -153,7 +153,6 @@ class EpubFile(var book: Book) {
         val includeNextChapterResource = !endFragmentId.isNullOrBlank()
         /*一些书籍依靠href索引的resource会包含多个章节，需要依靠fragmentId来截取到当前章节的内容*/
         /*注:这里较大增加了内容加载的时间，所以首次获取内容后可存储到本地cache，减少重复加载*/
-            val contents = epubBookContents ?: return null
         for (res in contents) {
             if (!findChapterFirstSource) {
                 if (currentChapterFirstResourceHref != res.href) continue
@@ -197,8 +196,6 @@ class EpubFile(var book: Book) {
         }
         return HtmlFormatter.formatKeepImg(html)
     }
-        return null
-    }
 
     private fun getBody(res: Resource, startFragmentId: String?, endFragmentId: String?): Element {
         // Jsoup可能会修复不规范的xhtml文件 解析处理后再获取