当然，下面是一个关于如何使用 dynamic_theme_mode 插件在 Flutter 中实现主题动态切换的代码示例。这个插件允许你轻松地管理应用的日间和夜间主题模式。

首先，确保你已经在 pubspec.yaml 文件中添加了 dynamic_theme 依赖：

dependencies:
  flutter:
    sdk: flutter
  dynamic_theme: ^3.0.1  # 请检查最新版本号

然后，运行 flutter pub get 来获取依赖。

接下来，你可以按照以下步骤实现主题动态切换：

1. 定义主题数据：

在你的 main.dart 文件中，首先定义两个主题（例如，日间和夜间主题）：

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

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

class MyApp extends StatelessWidget {
  final ThemeData lightTheme = ThemeData(
    brightness: Brightness.light,
    primarySwatch: Colors.blue,
    // 其他主题配置...
  );

  final ThemeData darkTheme = ThemeData(
    brightness: Brightness.dark,
    primarySwatch: Colors.blueGrey,
    // 其他主题配置...
  );

  @override
  Widget build(BuildContext context) {
    return DynamicTheme(
      defaultBrightness: Brightness.light, // 默认亮度
      data: (brightness) {
        return brightness == Brightness.light ? lightTheme : darkTheme;
      },
      themedWidgetBuilder: (context, theme) {
        return MaterialApp(
          title: 'Flutter Demo',
          theme: theme,
          home: MyHomePage(),
          builder: (context, child) {
            // 包裹 MaterialApp 以处理状态重建（可选）
            return DynamicTheme.builder(
              theme: theme,
              builder: (context, widget) => widget!,
              child: child,
            );
          },
        );
      },
    );
  }
}

1. 创建一个切换主题的按钮：

在你的 MyHomePage 中，添加一个按钮来切换主题：

import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:dynamic_theme/dynamic_theme.dart';

class MyHomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Theme Switcher Demo'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              'Current Theme Mode: ${Theme.of(context).brightness == Brightness.light ? 'Light' : 'Dark'}',
              style: Theme.of(context).textTheme.headline4,
            ),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: () {
                DynamicTheme.of(context).setBrightness(
                  Theme.of(context).brightness == Brightness.light
                      ? Brightness.dark
                      : Brightness.light,
                );
              },
              child: Text('Switch Theme'),
            ),
          ],
        ),
      ),
    );
  }
}

在这个例子中，我们使用了 DynamicTheme.of(context).setBrightness() 方法来切换主题的亮度。这会自动触发 DynamicTheme 小部件的重建，并应用新的主题。

1. 持久化主题设置（可选）：

如果你希望应用重启后仍然保持用户选择的主题，可以使用 shared_preferences 或其他存储机制来持久化主题设置。在启动时，根据存储的值设置初始主题。

这里是一个简单的例子，使用 shared_preferences 来持久化主题设置：

import 'package:shared_preferences/shared_preferences.dart';

// 在 MyApp 的 build 方法中添加以下代码来初始化主题
@override
Widget build(BuildContext context) {
  return FutureBuilder<SharedPreferences>(
    future: SharedPreferences.getInstance(),
    builder: (context, snapshot) {
      if (snapshot.connectionState == ConnectionState.done) {
        final SharedPreferences prefs = snapshot.data!;
        bool isDarkMode = prefs.getBool('isDarkMode') ?? false;

        return DynamicTheme(
          defaultBrightness: isDarkMode ? Brightness.dark : Brightness.light,
          data: (brightness) {
            return brightness == Brightness.light ? lightTheme : darkTheme;
          },
          themedWidgetBuilder: (context, theme) {
            return MaterialApp(
              title: 'Flutter Demo',
              theme: theme,
              home: MyHomePage(
                initialBrightness: brightness,
              ),
              builder: (context, child) {
                return DynamicTheme.builder(
                  theme: theme,
                  builder: (context, widget) => widget!,
                  child: child,
                );
              },
            );
          },
        );
      } else {
        return CircularProgressIndicator();
      }
    },
  );
}

// 在 MyHomePage 中添加对 SharedPreferences 的依赖和保存逻辑
class MyHomePage extends StatefulWidget {
  final Brightness initialBrightness;

  MyHomePage({Key? key, required this.initialBrightness}) : super(key: key);

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

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Theme Switcher Demo'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'Current Theme Mode: ${Theme.of(context).brightness == Brightness.light ? 'Light' : 'Dark'}',
              style: Theme.of(context).textTheme.headline4,
            ),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: () async {
                bool isDarkMode =
                    Theme.of(context).brightness == Brightness.dark;
                DynamicTheme.of(context).setBrightness(
                  isDarkMode ? Brightness.light : Brightness.dark,
                );

                final SharedPreferences prefs = await SharedPreferences.getInstance();
                prefs.setBool('isDarkMode', isDarkMode ? false : true);
              },
              child: Text('Switch Theme'),
            ),
          ],
        ),
      ),
    );
  }
}

以上代码展示了如何使用 dynamic_theme_mode 插件来实现主题动态切换，并持久化用户的主题选择。希望这对你有所帮助！