Flutter开发（2）—— 第一个App

本文示例开发环境: Mac 11.2.3 / Android Studio 4.1.2
教程相关:
官网: https://flutter.dev/
Flutter中文网: https://flutterchina.club/
GitHub: https://github.com/flutter/flutter
bilibili视频教程: https://www.bilibili.com/video/BV1S4411E7LY?p=25&t=5

在 macOS 上安装和配置 Flutter 开发环境

https://flutterchina.club/get-started/install/

第一个App

新建Flutter工程

新建App

工程名

包名 / Bundle ID

Run

第一个App

code

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);
  
  final String title;

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

class _MyHomePageState extends State {
  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: [
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headline4,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

编译为本机

Flutter应用程序是用单个代码库 (Dart) 开发的，然后框架将代码库编译为本地iOS或Android。在目标平台中，仅代码的UI组件会转换为等效的本机UI组件。
我们在上面例子中demo1的根目录下, 会找到对应的Android和iOS工程:

Android.png

iOS.png

使用 Android Studio 或者 Xcode 能分别运行工程并生成对应的 Android/iOS App.