Dart 语言优势

• Dart 既可以支持 JIT（动态编译），也可以支持 AOT（静态编译）。在开发阶段热加载的功能就是基于JIT，打包后的程序是通过AOT编译程序。

// 导入库
import 'package:flutter/material.dart';
// 程序入口
void main() {
  runApp(const MyApp());
}
// 无状态组件MyApp
class MyApp extends StatelessWidget {
  // 构造函数
  const MyApp({Key? key}) : super(key: key);
  // 这里是程序的根节点
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

变量声明

var content = 'Dart 语法'; // Declare and initialize a variable.
var switchOn = false;
var current = 0;
String name = "by 小德";
int count = 0;
dynamic example = 'example';
Object index = 100;

常量：final和const

// 当类创建的时候初始化
final content = 'Dart 语法'; 
// 编译时初始化
static const bool switchOn = false;

Dart 支持的数据类型