how to add square container in a border of a container in flutter-CodePudding

So im new to flutter and I was wondering if how can I make a sqaure with a square inside but it center the border of the square? sorry for my bad explaination I will provide an image for it.

CodePudding user response：

You can use a Stack for that. for example:

return Stack(
  alignment: Alignment.bottomCenter,
  children: [
    Container(
      margin: const EdgeInsets.only(bottom: 20),
      width: 100, 
      height: 100,
      color: Colors.red
    ),
    Container(
      width: 60, 
      height: 60,
      color: Colors.yellow
    )
  ],);

Result:

CodePudding user response：

Please refer to below code, you can use stack and Positioned

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(
      // Application name
      title: 'Flutter Hello World',
      // Application theme data, you can set the colors for the application as
      // you want
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      // A widget which will be started on application startup
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatelessWidget {
  
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        // The title text which will be shown on the action bar
        title: Text("title"),
      ),
      body: Stack(
        clipBehavior: Clip.none,
        alignment: Alignment.center,
        children: [
          Container(
            height: 130.0,
            width: 190.0,
            decoration: BoxDecoration(
              border: Border.all(
                color: Colors.black,
                width: 2.0,
              ),
            ),
          ),
          Positioned(
            bottom: -40.0,
            child: Container(
              
              height: 90.0,
              width: 130.0,
              decoration: BoxDecoration(
                color: Colors.white,
                border: Border.all(
                  color: Colors.black,
                  width: 2.0,
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }
}

Try this using Stack with Alignment

 MyHomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final size = MediaQuery.of(context).size;
    return Scaffold(
      appBar: AppBar(
        // The title text which will be shown on the action bar
        title: Text("title"),
      ),
      body: Stack(
        clipBehavior: Clip.none,
        alignment: Alignment.center,
        children: [
          Container(
            width: size.width * 0.40,
            height: size.height * 0.20,
            decoration: BoxDecoration(
              border: Border.all(
                color: Colors.black,
                width: 2.0,
              ),
            ),
          ),
          Align(
            alignment: Alignment(0, 0.25),
            child: Container(
              width: size.width * 0.25,
              height: size.height * 0.15,
              decoration: BoxDecoration(
                color: Colors.white,
                border: Border.all(
                  color: Colors.black,
                  width: 2.0,
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }
}