chore: save scroll pos

frontend/app_flowy/lib/plugins/board/application/group_controller.dart

@@ -1,7 +1,7 @@
 import 'package:flowy_sdk/log.dart';
 import 'package:flowy_sdk/protobuf/flowy-error/errors.pb.dart';
 import 'package:flowy_sdk/protobuf/flowy-grid/protobuf.dart';
-
+import 'package:protobuf/protobuf.dart';
 import 'group_listener.dart';
 
 typedef OnGroupError = void Function(FlowyError);
@@ -42,7 +42,6 @@ class GroupController {
 
           for (final insertedRow in changeset.insertedRows) {
             final index = insertedRow.hasIndex() ? insertedRow.index : null;
-
             if (insertedRow.hasIndex() &&
                 group.rows.length > insertedRow.index) {
               group.rows.insert(insertedRow.index, insertedRow.row);
@@ -50,11 +49,7 @@ class GroupController {
               group.rows.add(insertedRow.row);
             }
 
-            delegate.insertRow(
-              group,
-              insertedRow.row,
-              index,
-            );
+            delegate.insertRow(group, insertedRow.row, index);
           }
 
           for (final updatedRow in changeset.updatedRows) {
@@ -74,6 +69,29 @@ class GroupController {
     });
   }
 
+  // GroupChangesetPB _transformChangeset(GroupChangesetPB changeset) {
+  //   final insertedRows = changeset.insertedRows
+  //       .where(
+  //         (delete) => !changeset.deletedRows.contains(delete.row.id),
+  //       )
+  //       .toList();
+
+  //   final deletedRows = changeset.deletedRows
+  //       .where((deletedRowId) =>
+  //           changeset.insertedRows
+  //               .indexWhere((insert) => insert.row.id == deletedRowId) ==
+  //           -1)
+  //       .toList();
+
+  //   return changeset.rebuild((rebuildChangeset) {
+  //     rebuildChangeset.insertedRows.clear();
+  //     rebuildChangeset.insertedRows.addAll(insertedRows);
+
+  //     rebuildChangeset.deletedRows.clear();
+  //     rebuildChangeset.deletedRows.addAll(deletedRows);
+  //   });
+  // }
+
   Future<void> dispose() async {
     _listener.stop();
   }

frontend/app_flowy/packages/appflowy_board/lib/src/widgets/board.dart

@@ -184,7 +184,7 @@ class _AFBoardContentState extends State<AFBoardContent> {
         );
 
         final reorderFlex = ReorderFlex(
-          key: widget.key,
+          key: const PageStorageKey<String>('AFBoardContent'),
           config: widget.reorderFlexConfig,
           scrollController: widget.scrollController,
           onDragStarted: widget.onDragStarted,
@@ -242,27 +242,23 @@ class _AFBoardContentState extends State<AFBoardContent> {
           value: widget.dataController.getColumnController(columnData.id),
           child: Consumer<AFBoardColumnDataController>(
             builder: (context, value, child) {
-              final scrollController =
-                  widget.columnState.scrollController(columnData.id);
               final boardColumn = AFBoardColumnWidget(
-                key: ValueKey(columnData.id),
+                key: const PageStorageKey<String>('AFBoardColumnWidget'),
                 margin: _marginFromIndex(columnIndex),
                 itemMargin: widget.config.columnItemPadding,
                 headerBuilder: _buildHeader,
                 footBuilder: widget.footBuilder,
                 cardBuilder: widget.cardBuilder,
                 dataSource: dataSource,
-                scrollController: scrollController,
+                scrollController: ScrollController(),
                 phantomController: widget.phantomController,
                 onReorder: widget.dataController.moveColumnItem,
                 cornerRadius: widget.config.cornerRadius,
                 backgroundColor: widget.config.columnBackgroundColor,
               );
 
-              widget.columnState.addColumn(
-                columnData.id,
-                boardColumn.globalKey,
-              );
+              widget.columnState
+                  .addColumn(columnData.id, boardColumn.globalKey);
 
               return ConstrainedBox(
                 constraints: widget.columnConstraints,
@@ -350,10 +346,4 @@ class BoardColumnState {
     final widget = flexGlobalKey.currentWidget as ReorderFlex;
     return widget;
   }
-
-  ScrollController scrollController(String columnId) {
-    ScrollController scrollController = ScrollController();
-
-    return scrollController;
-  }
 }

frontend/app_flowy/packages/appflowy_board/lib/src/widgets/board_column/board_column.dart

@@ -65,7 +65,6 @@ class AFBoardColumnWidget extends StatefulWidget {
   final AFBoardColumnDataDataSource dataSource;
   final ScrollController? scrollController;
   final ReorderFlexConfig config;
-
   final OnColumnDragStarted? onDragStarted;
   final OnColumnReorder onReorder;
   final OnColumnDragEnded? onDragEnded;
@@ -88,7 +87,7 @@ class AFBoardColumnWidget extends StatefulWidget {
 
   final Color backgroundColor;
 
-  final GlobalKey globalKey = GlobalKey();
+  final GlobalKey globalKey;
 
   AFBoardColumnWidget({
     Key? key,
@@ -98,14 +97,15 @@ class AFBoardColumnWidget extends StatefulWidget {
     required this.onReorder,
     required this.dataSource,
     required this.phantomController,
-    this.onDragStarted,
     this.scrollController,
+    this.onDragStarted,
     this.onDragEnded,
     this.margin = EdgeInsets.zero,
     this.itemMargin = EdgeInsets.zero,
     this.cornerRadius = 0.0,
     this.backgroundColor = Colors.transparent,
-  })  : config = const ReorderFlexConfig(),
+  })  : globalKey = GlobalKey(),
+        config = const ReorderFlexConfig(),
         super(key: key);
 
   @override
@@ -115,7 +115,6 @@ class AFBoardColumnWidget extends StatefulWidget {
 class _AFBoardColumnWidgetState extends State<AFBoardColumnWidget> {
   final GlobalKey _columnOverlayKey =
       GlobalKey(debugLabel: '$AFBoardColumnWidget overlay key');
-
   late BoardOverlayEntry _overlayEntry;
 
   @override