Flutter游戏插件snake的使用

Flutter游戏插件snake的使用

1. 创建 SnakeGame

首先，我们需要创建一个 SnakeGame 实例。这个实例将负责管理游戏的状态和逻辑。

final snakeGame = SnakeGame(
  renderer: render, // 渲染回调函数
  boardWidth: 16,   // 游戏板的宽度
  boardHeight: 16,  // 游戏板的高度
  initialSnakeX: 3, // 蛇的初始X坐标
  initialSnakeY: 0, // 蛇的初始Y坐标
  initialSnakeDirection: SnakeDirection.right, // 蛇的初始方向
  initialSnakeSize: 3, // 蛇的初始长度
  maxTicksBeforeFood: 20, // 最大等待时间（以tick为单位）生成食物
  minTicksBeforeFood: 5,  // 最小等待时间（以tick为单位）生成食物
  startWithFood: false,   // 游戏开始时是否生成食物
);

2. 设置时钟

为了使游戏能够持续运行，我们需要设置一个定时器来定期调用 tick() 方法，以更新游戏状态。

final clock = Timer.periodic(
  const Duration(milliseconds: 250), // 每250毫秒触发一次
  (clock) {
    if (_snakeGame.completed) { // 如果游戏结束，取消定时器
      clock.cancel();
    } else {
      snakeGame.tick(); // 更新游戏状态
    }
  },
);

3. 处理渲染回调

在Flutter中，我们可以通过 setState() 来触发UI的重新绘制。我们需要定义一个渲染回调函数 _render()，并在 initState() 中初始化 SnakeGame 和游戏板。

class _SnakeGameWidgetState extends State<SnakeGameWidget> {
  late final SnakeGame _snakeGame;
  late final List<List<SnakeItem>> _board;

  // 渲染回调函数
  void _render() => setState(() => _board = _snakeGame.getBoardWithSnake());

  @override
  void initState() {
    super.initState();
    _snakeGame = SnakeGame(
      renderer: _render, // 设置渲染回调
      boardWidth: 16,
      boardHeight: 16,
      initialSnakeX: 3,
      initialSnakeY: 0,
      initialSnakeDirection: SnakeDirection.right,
      initialSnakeSize: 3,
      maxTicksBeforeFood: 20,
      minTicksBeforeFood: 5,
      startWithFood: false,
    );
    _board = _snakeGame.getBoardWithSnake(); // 获取初始的游戏板
  }

  @override
  Widget build(BuildContext context) => SnakeGameBoardDisplay(board: _board); // 渲染游戏板
}

4. 添加控制

为了让玩家能够控制蛇的方向，我们需要监听键盘事件并根据按键更改蛇的移动方向。

final key = getPressedKey();
switch (key) {
  case Key.upArrow:
    snakeGame.directionNextTick = SnakeDirection.up; // 下次移动时向上
    break;
  case Key.downArrow:
    snakeGame.directionNextTick = SnakeDirection.down; // 下次移动时向下
    break;
  case Key.leftArrow:
    snakeGame.directionNextTick = SnakeDirection.left; // 下次移动时向左
    break;
  case Key.rightArrow:
    snakeGame.directionNextTick = SnakeDirection.right; // 下次移动时向右
    break;
}

5. 等待游戏结束

当游戏结束时，我们可以等待 gameFuture 完成，并显示游戏结束的消息。

await _snakeGame.gameFuture;
alert('Game over! Score: ${snakeGame.score}'); // 显示游戏结束信息和分数

6. 完整示例代码

以下是一个完整的Flutter示例代码，展示了如何使用 snake 插件来创建一个简单的贪吃蛇游戏。

import 'package:flutter/material.dart';
import 'package:snake/snake.dart'; // 引入snake包

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Snake Game',
      theme: ThemeData(
        primarySwatch: Colors.green,
      ),
      home: SnakeGameScreen(),
    );
  }
}

class SnakeGameScreen extends StatefulWidget {
  @override
  _SnakeGameScreenState createState() => _SnakeGameScreenState();
}

class _SnakeGameScreenState extends State<SnakeGameScreen> {
  late final SnakeGame _snakeGame;
  late final List<List<SnakeItem>> _board;

  // 渲染回调函数
  void _render() => setState(() => _board = _snakeGame.getBoardWithSnake());

  @override
  void initState() {
    super.initState();
    _snakeGame = SnakeGame(
      renderer: _render, // 设置渲染回调
      boardWidth: 16,
      boardHeight: 16,
      initialSnakeX: 3,
      initialSnakeY: 0,
      initialSnakeDirection: SnakeDirection.right,
      initialSnakeSize: 3,
      maxTicksBeforeFood: 20,
      minTicksBeforeFood: 5,
      startWithFood: false,
    );
    _board = _snakeGame.getBoardWithSnake(); // 获取初始的游戏板

    // 设置定时器，每250毫秒更新一次游戏状态
    Timer.periodic(const Duration(milliseconds: 250), (timer) {
      if (_snakeGame.completed) {
        timer.cancel(); // 游戏结束时取消定时器
      } else {
        _snakeGame.tick(); // 更新游戏状态
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Flutter Snake Game'),
      ),
      body: Column(
        children: [
          Expanded(
            child: SnakeGameBoardDisplay(board: _board), // 渲染游戏板
          ),
          Row(
            mainAxisAlignment: MainAxisAlignment.spaceEvenly,
            children: [
              ElevatedButton(
                onPressed: () => _snakeGame.directionNextTick = SnakeDirection.up,
                child: Icon(Icons.arrow_upward),
              ),
              ElevatedButton(
                onPressed: () => _snakeGame.directionNextTick = SnakeDirection.left,
                child: Icon(Icons.arrow_back),
              ),
              ElevatedButton(
                onPressed: () => _snakeGame.directionNextTick = SnakeDirection.right,
                child: Icon(Icons.arrow_forward),
              ),
              ElevatedButton(
                onPressed: () => _snakeGame.directionNextTick = SnakeDirection.down,
                child: Icon(Icons.arrow_downward),
              ),
            ],
          ),
        ],
      ),
    );
  }
}

// 游戏板的显示组件
class SnakeGameBoardDisplay extends StatelessWidget {
  final List<List<SnakeItem>> board;

  SnakeGameBoardDisplay({required this.board});

  @override
  Widget build(BuildContext context) {
    return GridView.builder(
      gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
        crossAxisCount: board[0].length, // 列数
      ),
      itemCount: board.length * board[0].length, // 总单元格数
      itemBuilder: (context, index) {
        final row = index ~/ board[0].length;
        final col = index % board[0].length;
        final item = board[row][col];

        // 根据单元格的内容显示不同的颜色
        if (item == SnakeItem.snake) {
          return Container(color: Colors.green);
        } else if (item == SnakeItem.food) {
          return Container(color: Colors.red);
        } else {
          return Container(color: Colors.grey);
        }
      },
    );
  }
}

7. 示例图片

8. 许可证

该插件使用MIT许可证，具体内容如下：

MIT License

Copyright (c) 2021 hacker1024

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.