dart_topic_pack 是一个用于 Flutter 应用的主题管理插件。它允许开发者轻松地管理和切换应用的主题，支持自定义主题、动态主题切换等功能。以下是如何使用 dart_topic_pack 插件的基本步骤：

1. 添加依赖

首先，在 pubspec.yaml 文件中添加 dart_topic_pack 的依赖：

dependencies:
  flutter:
    sdk: flutter
  dart_topic_pack: ^1.0.0  # 请使用最新版本

然后运行 flutter pub get 来安装依赖。

2. 创建主题

在使用 dart_topic_pack 之前，你需要定义你的应用主题。你可以创建多个主题，例如 lightTheme 和 darkTheme。

import 'package:flutter/material.dart';

final ThemeData lightTheme = ThemeData(
  primarySwatch: Colors.blue,
  brightness: Brightness.light,
);

final ThemeData darkTheme = ThemeData(
  primarySwatch: Colors.indigo,
  brightness: Brightness.dark,
);

3. 初始化主题管理

在你的应用启动时，初始化 dart_topic_pack 并设置默认主题。

import 'package:flutter/material.dart';
import 'package:dart_topic_pack/dart_topic_pack.dart';

void main() {
  // 初始化主题管理
  TopicPack.initialize(
    themes: {
      'light': lightTheme,
      'dark': darkTheme,
    },
    defaultTheme: 'light',
  );

  runApp(MyApp());
}

4. 使用主题

在应用中使用 TopicPack 来获取当前主题，并在 MaterialApp 中应用主题。

class MyApp extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Theme Demo',
      theme: TopicPack.currentTheme, // 使用当前主题
      home: MyHomePage(),
    );
  }
}

5. 动态切换主题

你可以在应用中的任何地方使用 TopicPack 来动态切换主题。

class MyHomePage extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Theme Demo'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            ElevatedButton(
              onPressed: () {
                TopicPack.setTheme('light'); // 切换到亮色主题
              },
              child: Text('Light Theme'),
            ),
            ElevatedButton(
              onPressed: () {
                TopicPack.setTheme('dark'); // 切换到暗色主题
              },
              child: Text('Dark Theme'),
            ),
          ],
        ),
      ),
    );
  }
}

6. 监听主题变化

如果你需要在主题变化时执行某些操作，你可以监听主题变化事件。

TopicPack.addListener(() {
  // 主题变化时的回调
  print('Theme changed to ${TopicPack.currentThemeName}');
});

7. 持久化主题

你可以将用户选择的主题保存到本地存储中，以便在应用重启时恢复主题。

import 'package:shared_preferences/shared_preferences.dart';

void saveTheme(String themeName) async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  await prefs.setString('theme', themeName);
}

Future<String?> loadTheme() async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  return prefs.getString('theme');
}

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  
  String? savedTheme = await loadTheme();
  
  TopicPack.initialize(
    themes: {
      'light': lightTheme,
      'dark': darkTheme,
    },
    defaultTheme: savedTheme ?? 'light',
  );

  runApp(MyApp());
}

8. 完整示例

以下是一个完整的示例，展示了如何使用 dart_topic_pack 管理主题：

import 'package:flutter/material.dart';
import 'package:dart_topic_pack/dart_topic_pack.dart';
import 'package:shared_preferences/shared_preferences.dart';

final ThemeData lightTheme = ThemeData(
  primarySwatch: Colors.blue,
  brightness: Brightness.light,
);

final ThemeData darkTheme = ThemeData(
  primarySwatch: Colors.indigo,
  brightness: Brightness.dark,
);

void saveTheme(String themeName) async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  await prefs.setString('theme', themeName);
}

Future<String?> loadTheme() async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  return prefs.getString('theme');
}

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  
  String? savedTheme = await loadTheme();
  
  TopicPack.initialize(
    themes: {
      'light': lightTheme,
      'dark': darkTheme,
    },
    defaultTheme: savedTheme ?? 'light',
  );

  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Theme Demo',
      theme: TopicPack.currentTheme,
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Theme Demo'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            ElevatedButton(
              onPressed: () {
                TopicPack.setTheme('light');
                saveTheme('light');
              },
              child: Text('Light Theme'),
            ),
            ElevatedButton(
              onPressed: () {
                TopicPack.setTheme('dark');
                saveTheme('dark');
              },
              child: Text('Dark Theme'),
            ),
          ],
        ),
      ),
    );
  }
}