// main.dart
import 'package:flutter/material.dart';
void main() {
  runApp(const MyApp());
}
class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: '大前端之旅小课堂',
      theme: ThemeData(
        primarySwatch: Colors.indigo,
      ),
      home: const HomePage(),
    );
  }
}
class HomePage extends StatefulWidget {
  const HomePage({Key? key}) : super(key: key);
  @override
  _HomePageState createState() => _HomePageState();
}
class _HomePageState extends State<HomePage> {
  bool _isSHown = true;
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('大前端之旅小课堂'),
        actions: [
          Switch(
              activeColor: Colors.white,
              activeTrackColor: Colors.yellow,
              value: _isSHown,
              onChanged: (_) {
                setState(() {
                  _isSHown = !_isSHown;
                });
              })
        ],
      ),
      body: GridPaper(
        // Set the color of the lines
        color: _isSHown ? Colors.black54 : Colors.transparent,
        // The number of major divisions within each primary grid cell
        divisions: 2,
        // The number of minor divisions within each major division, including the major division itself
        subdivisions: 2,
        // GridPaper's child
        child: Container(
          alignment: Alignment.center,
          width: double.infinity,
          height: double.infinity,
          color: Colors.yellow.shade200,
          child: const Center(
            child: Text(
              '新年快乐',
              style: TextStyle(fontSize: 150, color: Colors.red),
            ),
          ),
        ),
      ),
    );
  }
}
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