Flutter框架：从入门到实战，构建跨平台移动应用的全流程解析

import 'package:flutter/material.dart';
 
void main() => runApp(MyApp());
 
class MyApp extends StatelessWidget {
  // 此处可以定义应用的主题样式、字体样式等
  final ThemeData theme = ThemeData(
    primarySwatch: Colors.blue,
    visualDensity: VisualDensity.adaptivePlatformDensity,
  );
 
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: theme,
      home: MyHomePage(title: 'Flutter 实战'),
    );
  }
}
 
class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);
 
  final String title;
 
  @override
  _MyHomePageState createState() => _MyHomePageState();
}
 
class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;
 
  void _incrementCounter() {
    setState(() {
      _counter++;
    });
  }
 
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              '点击次数:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headline4,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: '增加',
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

这段代码是一个简单的Flutter应用示例，它展示了如何创建一个包含计数器逻辑的页面，并且使用了Flutter的Material组件和主题定义。通过这个例子，开发者可以学习到如何在Flutter中构建用户界面、管理状态和响应用户输入。