优化

app/src/main/java/io/legado/app/ui/book/read/ReadBookActivity.kt

@@ -1507,7 +1507,7 @@ class ReadBookActivity : BaseReadBookActivity(),
         popupAction.dismiss()
         binding.readView.onDestroy()
         ReadBook.unregister(this)
-        if (!ReadBook.inBookshelf) {
+        if (!ReadBook.inBookshelf && !isChangingConfigurations) {
             viewModel.removeFromBookshelf(null)
         }
         if (!BuildConfig.DEBUG) {