更新android studio 到 4.1

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

@@ -333,7 +333,10 @@ class BgTextConfigDialog : BaseDialogFragment(), FileChooserDialog.CallBack {
                 val bgName = FileUtils.getName(config.bgStr())
                 val bgPath = FileUtils.getPath(requireContext().externalFilesDir, "bg", bgName)
                 if (!FileUtils.exist(bgPath)) {
-                    FileUtils.getFile(configDir, bgName).copyTo(File(bgPath))
+                    val bgFile = FileUtils.getFile(configDir, bgName)
+                    if (bgFile.exists()) {
+                        bgFile.copyTo(File(bgPath))
+                    }
                 }
             }
             ReadBookConfig.durConfig = config