Update PreferKey.kt

新增自定义“导入文件名”选项

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

@@ -29,6 +29,7 @@ object PreferKey {
     const val bookshelfLayout = "bookshelfLayout"
     const val bookshelfSort = "bookshelfSort"
     const val bookExportFileName = "bookExportFileName"
+    const val bookImportFileName = "bookImportFileName"
     const val recordLog = "recordLog"
     const val processText = "process_text"
     const val cleanCache = "cleanCache"
@@ -92,4 +93,4 @@ object PreferKey {
     const val cNBBackground = "colorBottomBackgroundNight"
     const val bgImageN = "backgroundImageNight"
 
-}
+}