import 'package:flutter/material.dart';

void main() {
  runApp(MaterialApp(
    home: Scaffold(
      appBar: AppBar(
        title: const Text('Welcome'),
      ),
      body: Center(
        child: Container(
          alignment: Alignment.topCenter,
          height: 260,
          width: 260,
          decoration: const BoxDecoration(
            color: Colors.blue,
            //borderRadius: BorderRadius.all(Radius.circular(20)),
            borderRadius: BorderRadius.only(
              topLeft: Radius.circular(20),
              topRight: Radius.circular(30),
              bottomLeft: Radius.elliptical(100, 50),
              bottomRight: Radius.elliptical(70, 150),
            ),
            boxShadow: [
              BoxShadow(
                color: Colors.grey.withOpacity(0.5),
                blurRadius: 10,
                spreadRadius: 5,
                offset: Offset(.5, 0),
                blurStyle: BlurStyle.outer,
              ),
            ],
          ),
          padding: const EdgeInsets.all(10.0),
          margin: const EdgeInsets.only(left: 10),
          child: const Text(
            'Hello World!',
            //textAlign: TextAlign.center,
            style: TextStyle(
              fontSize: 50,
              color: Colors.white,
              fontWeight: FontWeight.bold,
            ),
          ),
        ),
      ),
    ),
  ));
}

CodePudding user response：

Please remove "const" before BoxDecoration widget. And then you could assign withOpacity for Color in the BoxShadow.

Before

After

CodePudding user response：

Try this, Need to remove const

Center(
        child: Container(
          alignment: Alignment.topCenter,
          height: 260,
          width: 260,
          decoration: BoxDecoration(
              color: Colors.blue,
              borderRadius: BorderRadius.only(
                topLeft: Radius.circular(20),
                topRight: Radius.circular(30),
                bottomLeft: Radius.elliptical(100, 50),
                bottomRight: Radius.elliptical(70, 150),
              ),
              boxShadow: [
                BoxShadow(
                  color: Colors.grey.withOpacity(0.5),
                  blurRadius: 10,
                  spreadRadius: 5,
                  offset: Offset(.5, 0),
                  blurStyle: BlurStyle.outer,
                ),
              ]),
          padding: const EdgeInsets.all(10.0),
          margin: const EdgeInsets.only(left: 10),
          child: const Text(
            'Hello World!',
            //textAlign: TextAlign.center,
            style: TextStyle(
              fontSize: 50,
              color: Colors.white,
              fontWeight: FontWeight.bold,
            ),
          ),
        ),
      ),