flutter_chess_board

A full-fledged Chessboard widget for Flutter. Includes the Chessboard widget, stores game state, and includes a controller to check and manipulate game state.

Full support for formats like PGN, FEN as well as ASCII. Supports multiple colors and displaying arrows on the board. Easy access to making / undoing moves on the board.

Note: v1.0+ is a major refactor and the earlier architecture which used scoped_model internally is no longer in use. The ChessBoardController now stores the state of the game as well as contains options to change and check state. Arrows on the board are now supported.

Setting Up

Add a ChessBoard widget and attach a ChessBoardController to it.

Let's also set the board color and specify the board orientation (default is towards white).

import 'package:flutter/material.dart';
import 'package:flutter_chess_board/flutter_chess_board.dart';
        
class HomePage extends StatefulWidget {
  const HomePage({Key? key}) : super(key: key);

  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  ChessBoardController controller = ChessBoardController();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Chess Demo'),
      ),
      body: Center(
        child: ChessBoard(
          controller: controller,
          boardColor: BoardColor.orange,
          boardOrientation: PlayerColor.white,
        ),
      ),
    );
  }
}

Let's try to display arrows on the board and also display moves of the current game:

import 'package:flutter/material.dart';
import 'package:flutter_chess_board/flutter_chess_board.dart';
        
class HomePage extends StatefulWidget {
  const HomePage({Key? key}) : super(key: key);

  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  ChessBoardController controller = ChessBoardController();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Chess Demo'),
      ),
      body: Column(
        children: [
          Expanded(
            child: Center(
              child: ChessBoard(
                controller: controller,
                boardColor: BoardColor.orange,
                lastMoveHighlightColor: Colors.yellow.withOpacity(.3),
                arrows: [
                  BoardArrow(
                    from: 'd2',
                    to: 'd4',
                    color: Colors.red.withOpacity(0.5),
                  ),
                ],
                highlightedSquares: [
                  BoardHighlightedSquare(
                    'd2',
                    color: Colors.green.withOpacity(.5),
                  ),
                ],
                boardOrientation: PlayerColor.white,
              ),
            ),
          ),
          Expanded(
            child: ValueListenableBuilder<Chess>(
              valueListenable: controller,
              builder: (context, game, _) {
                return Text(
                  controller.getSan().fold(
                        '',
                        (previousValue, element) =>
                            previousValue + '\n' + (element ?? ''),
                      ),
                );
              },
            ),
          ),
        ],
      ),
    );
  }
}

This gives us:

Watch for game changes

You can listen to game state changes (move, half moves, etc) using either a listener or a ValueListenableBuilder:

  ChessBoardController controller = ChessBoardController();
  
  @override
  void initState() {
    super.initState();
    controller.addListener(() {
      // Do something here
    });
  }

  ValueListenableBuilder<Chess>(
    valueListenable: controller,
    builder: (context, game, _) {
      // Build on new game state
    },
  ),

Checking Game States

The ChessBoardController holds the game itself and you can do various kinds of things using it:

Load New Game

controller.loadPgn('demo PGN')

controller.loadFen('demo FEN')

Make Move:

controller.makeMove(from: 'd2', to: 'd4')

Undo Move:

controller.undoMove()

Check states:

controller.isCheckMate()

controller.isDraw()

controller.isStaleMate()

controller.isThreefoldRepetition

...and more...

Move Count

controller.getMoveCount()

controller.getHalfMoveCount()

Other Board Types

Import the package

To use this package, add chess_board as a dependency in your pubspec.yaml