flutter:适配屏幕(flutter_screenutil: ^5.6.1 / flutter 3.7.0 )

https://pub.dev/packages/flutter_screenutil

https://github.com/OpenFlutter/flutter_screenutil

flutter_screenutil: ^5.6.1

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

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

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

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});
  final String title;
  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    //设置尺寸（填写设计中设备的屏幕尺寸）如果设计基于750dp * 1334dp的屏幕
    ScreenUtil.init(
        context,
        designSize: Size(750, 1334)
    );
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Column(
          children: <Widget>[
        Row(
         children: <Widget>[
          Container(
          decoration: new BoxDecoration(
            color: Colors.blue,
          ),
          width:345.w,
          height: 200.w,
          margin:EdgeInsets.only(top:20.w,left:20.w),
        ),
            Container(
    decoration: new BoxDecoration(
    color: Colors.red,
    ),
    width:345.w,
    height: 200.w,
              margin:EdgeInsets.only(top:20.w,left:20.w),
    ),
        ]),
    Row(
    children: <Widget>[
            Container(
                decoration: new BoxDecoration(
                  color: Colors.green,
                ),
                width:345.w,
                height: 200.w,
              margin:EdgeInsets.only(top:20.w,left:20.w),
              alignment: Alignment.topLeft,
            ),
      ]),
          ],
        ),
    );
  }
}