我添加了备份和恢复功能的应用程序。但它只能在调试模式下正常工作，它不工作的最终版本和真实的的移动的。
有时备份和恢复工作在真实的的手机上，但当你删除应用程序并重新安装它，它不会恢复以前的数据。

/////////////////////Backup Button
                  SizedBox(
                    width: double.infinity,
                    child: ElevatedButton(
                      onPressed: () async {
                        final String? pathMyCart =
                            Hive.box<Cart>(cartBoxName).path;
                        final String? pathPersonCart =
                            Hive.box<CartPerson>(cartPersonBoxName).path;
                        String myCartName = 'carts.hive';
                        String personCartName = 'person.hive';
                        String path = await ExternalPath
                            .getExternalStoragePublicDirectory(
                                ExternalPath.DIRECTORY_DOWNLOADS);
                        String mainPath = '$path/MyCarts/Backup/';
                        await Permission.storage.request();
                        await Directory(mainPath).create(recursive: true);
                        Directory dirMyCart = Directory('$mainPath$myCartName');
                        Directory dirPersonCart =
                            Directory('$mainPath$personCartName');
                        String mainDirMyCart = dirMyCart.path;
                        String mainDirPersonCart = dirPersonCart.path;
                        File fileMyCartBackup = File('$pathMyCart');
                        File filePersonCartBackup = File('$pathPersonCart');
                        await fileMyCartBackup.copy(mainDirMyCart);
                        await filePersonCartBackup.copy(mainDirPersonCart);
                        ScaffoldMessenger.of(context).showSnackBar(
                          SnackBar(
                            content: Text(
                              'Backup completed successfully',
                              style: themeData.textTheme.headline6!
                                  .copyWith(color: themeData.primaryColor),
                            ),
                            backgroundColor:
                                themeData.textTheme.bodyText1!.color,
                          ),
                        );
                      },
                      child: Text(
                        'Backup',
                        style: themeData.textTheme.headline4!
                            .copyWith(color: themeData.backgroundColor),
                      ),
                    ),
                  ),

/////////////////////Restore Button
                  SizedBox(
                    width: double.infinity,
                    child: ElevatedButton(
                        onPressed: () async {
                          var status = await Permission.storage.status;
                          if (!status.isRestricted) {
                            await Permission.storage.request();
                          }

                          final String? pathMyCart =
                              Hive.box<Cart>(cartBoxName).path;
                          final String? pathPersonCart =
                              Hive.box<CartPerson>(cartPersonBoxName).path;
                          String myCartName = 'carts.hive';
                          String personCartName = 'person.hive';
                          String path = await ExternalPath
                              .getExternalStoragePublicDirectory(
                                  ExternalPath.DIRECTORY_DOWNLOADS);
                          String mainPath = '$path/MyCarts/Backup/';
                          Directory dirMyCart =
                              Directory('$mainPath$myCartName');
                          Directory dirPersonCart =
                              Directory('$mainPath$personCartName');
                          String mainDirMyCart = dirMyCart.path;
                          String mainDirPersonCart = dirPersonCart.path;
                          File fileMyCartBackup = File(mainDirMyCart);
                          File filePersonCartBackup = File(mainDirPersonCart);

                          fileMyCartBackup.copy('$pathMyCart');
                          filePersonCartBackup.copy('$pathPersonCart');

                          ScaffoldMessenger.of(context).showSnackBar(
                            SnackBar(
                              content: Text(
                                'The recovery was successful',
                                style: themeData.textTheme.headline6!
                                    .copyWith(color: themeData.primaryColor),
                              ),
                              backgroundColor:
                                  themeData.textTheme.bodyText1!.color,
                            ),
                          );
                        },
                        child: Text(
                          'recovery',
                          style: themeData.textTheme.headline4,
                        )),
                  ),

我已向应用程序授予以下权限

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE "/>

   <application
        android:requestLegacyExternalStorage="true"

解决方法是什么？请指导我