feat: 优化代码

app/src/main/java/io/legado/app/constant/EventBus.kt

@@ -21,4 +21,5 @@ object EventBus {
     const val WEB_SERVICE_STOP = "webServiceStop"
     const val UP_DOWNLOAD = "upDownload"
     const val UP_TABS = "upTabs"
+    const val SAVE_CONTENT = "saveContent"
 }

app/src/main/java/io/legado/app/help/BookHelp.kt

@@ -4,6 +4,7 @@ import android.net.Uri
 import androidx.documentfile.provider.DocumentFile
 import com.github.houbb.opencc4j.util.ZhConverterUtil
 import io.legado.app.App
+import io.legado.app.constant.EventBus
 import io.legado.app.constant.PreferKey
 import io.legado.app.data.entities.Book
 import io.legado.app.data.entities.BookChapter
@@ -68,6 +69,7 @@ object BookHelp {
                 subDirs = *arrayOf(cacheFolderName, bookFolderName(book))
             ).writeText(content)
         }
+        postEvent(EventBus.SAVE_CONTENT, bookChapter)
     }
 
     fun getChapterFiles(book: Book): List<String> {

app/src/main/java/io/legado/app/ui/download/DownloadActivity.kt

@@ -11,6 +11,7 @@ import io.legado.app.R
 import io.legado.app.base.BaseActivity
 import io.legado.app.constant.EventBus
 import io.legado.app.data.entities.Book
+import io.legado.app.data.entities.BookChapter
 import io.legado.app.help.BookHelp
 import io.legado.app.service.help.Download
 import io.legado.app.utils.applyTint
@@ -93,11 +94,14 @@ class DownloadActivity : BaseActivity(R.layout.activity_download) {
             if (it) {
                 menu?.findItem(R.id.menu_download)?.setIcon(R.drawable.ic_stop_black_24dp)
                 menu?.applyTint(this)
-                adapter.notifyItemRangeChanged(0, adapter.itemCount, true)
+                adapter.notifyItemRangeChanged(0, adapter.getActualItemCount(), true)
             } else {
                 menu?.findItem(R.id.menu_download)?.setIcon(R.drawable.ic_play_24dp)
                 menu?.applyTint(this)
             }
         }
+        observeEvent<BookChapter>(EventBus.SAVE_CONTENT) {
+            adapter.cacheChapters[it.bookUrl]?.add(it.url)
+        }
     }
 }