How can I add shadow to the widget in flutter?

Question

How can I add shadow to the widget like in the picture below?

This is my current widget code.

Answer 1

Check out BoxShadow and BoxDecoration

A Container can take a BoxDecoration (going off of the code you had originally posted) which takes a boxShadow

return Container(
  margin: EdgeInsets.only(left: 30, top: 100, right: 30, bottom: 50),
  height: double.infinity,
  width: double.infinity,
  decoration: BoxDecoration(
    color: Colors.white,
    borderRadius: BorderRadius.only(
      topLeft: Radius.circular(10),
        topRight: Radius.circular(10),
        bottomLeft: Radius.circular(10),
        bottomRight: Radius.circular(10)
    ),
    boxShadow: [
      BoxShadow(
        color: Colors.grey.withOpacity(0.5),
        spreadRadius: 5,
        blurRadius: 7,
        offset: Offset(0, 3), // changes position of shadow
      ),
    ],
  ),
)

Answer 2

Use BoxDecoration with BoxShadow.

Here is a visual demo manipulating the following options:

• opacity
• x offset
• y offset
• blur radius
• spread radius

The animated gif doesn't do so well with colors. You can try it yourself on a device.

Here is the full code for that demo:

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        body: ShadowDemo(),
      ),
    );
  }
}

class ShadowDemo extends StatefulWidget {
  @override
  _ShadowDemoState createState() => _ShadowDemoState();
}

class _ShadowDemoState extends State<ShadowDemo> {
  var _image = NetworkImage('https://placebear.com/300/300');

  var _opacity = 1.0;
  var _xOffset = 0.0;
  var _yOffset = 0.0;
  var _blurRadius = 0.0;
  var _spreadRadius = 0.0;

  @override
  Widget build(BuildContext context) {
    return Stack(
      children: <Widget>[
        Center(
          child:
          Container(
            decoration: BoxDecoration(
              color: Color(0xFF0099EE),
              boxShadow: [
                BoxShadow(
                  color: Color.fromRGBO(0, 0, 0, _opacity),
                  offset: Offset(_xOffset, _yOffset),
                  blurRadius: _blurRadius,
                  spreadRadius: _spreadRadius,
                )
              ],
            ),
            child: Image(image:_image, width: 100, height: 100,),
          ),
        ),
        Align(
          alignment: Alignment.bottomCenter,
          child: Padding(
            padding: const EdgeInsets.only(bottom: 80.0),
            child: Column(
              children: <Widget>[
                Spacer(),
                Slider(
                  value: _opacity,
                  min: 0.0,
                  max: 1.0,
                  onChanged: (newValue) =>
                  {
                    setState(() => _opacity = newValue)
                  },
                ),
                Slider(
                  value: _xOffset,
                  min: -100,
                  max: 100,
                  onChanged: (newValue) =>
                  {
                    setState(() => _xOffset = newValue)
                  },
                ),
                Slider(
                  value: _yOffset,
                  min: -100,
                  max: 100,
                  onChanged: (newValue) =>
                  {
                    setState(() => _yOffset = newValue)
                  },
                ),
                Slider(
                  value: _blurRadius,
                  min: 0,
                  max: 100,
                  onChanged: (newValue) =>
                  {
                    setState(() => _blurRadius = newValue)
                  },
                ),
                Slider(
                  value: _spreadRadius,
                  min: 0,
                  max: 100,
                  onChanged: (newValue) =>
                  {
                    setState(() => _spreadRadius = newValue)
                  },
                ),
              ],
            ),
          ),
        )
      ],
    );
  }
}