debugPrint('Move $fromGroupId:$fromIndex to $toGroupId:$toIndex');
},
);
```
Provide an initial value of the board by initializing the `AppFlowyGroupData`. It represents a group data and contains list of items. Each item displayed in the group requires to implement the `AppFlowyGroupItem` class.
```dart
void initState() {
final group1 = AppFlowyGroupData(id: "To Do", items: [
TextItem("Card 1"),
TextItem("Card 2"),
]);
final group2 = AppFlowyGroupData(id: "In Progress", items: [
TextItem("Card 3"),
TextItem("Card 4"),
]);
final group3 = AppFlowyGroupData(id: "Done", items: []);
controller.addGroup(group1);
controller.addGroup(group2);
controller.addGroup(group3);
super.initState();
}
class TextItem extends AppFlowyGroupItem {
final String s;
TextItem(this.s);
@override
String get id => s;
}
```
Finally, return a `AppFlowyBoard` widget in the build method.
* A Board widget is created via instantiating an `AppFlowyBoard` object.
* In the `AppFlowyBoard` object, you can find the `AppFlowyBoardController`, which is defined in board_data.dart, is feeded with prepopulated mock data. It also contains callback functions to materialize future user data.
* Three builders: AppFlowyBoardHeaderBuilder, AppFlowyBoardFooterBuilder, AppFlowyBoardCardBuilder. See below image for what they are used for.
Contributions are what make the open source community such an amazing place to learn, inspire, and create. Any contributions you make are greatly appreciated.
Please look at [CONTRIBUTING.md](https://appflowy.gitbook.io/docs/essential-documentation/contribute-to-appflowy/contributing-to-appflowy) for details.
## License
Distributed under the AGPLv3 License. See [LICENSE](https://github.com/AppFlowy-IO/AppFlowy-Docs/blob/main/LICENSE) for more information.