Bagaimana cara menambahkan bayangan ke widget dengan flutter?

Bagaimana cara menambahkan bayangan ke widget seperti pada gambar di bawah ini?

Ini adalah kode widget saya saat ini.

Lihat BoxShadow dan BoxDecoration

A Containerdapat mengambil BoxDecoration(keluar dari kode yang awalnya Anda posting) yang mengambilboxShadow

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
      ),
    ],
  ),
)

Screenshot

Gunakan BoxDecorationdengan BoxShadow.

Berikut adalah demo visual yang memanipulasi opsi berikut:

• kegelapan
• x offset
• y offset
• radius blur
• radius penyebaran

Gif animasi tidak cocok dengan warna. Anda dapat mencobanya sendiri di perangkat.

Berikut kode lengkap untuk demo itu:

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)
                  },
                ),
              ],
            ),
          ),
        )
      ],
    );
  }
}

Tangkapan layar:

Container(
  decoration: BoxDecoration(
    boxShadow: [
      BoxShadow(
        color: Colors.grey.withOpacity(0.8),
        spreadRadius: 10,
        blurRadius: 5,
        offset: Offset(0, 7), // changes position of shadow
      ),
    ],
  ),
  child: Image.asset(chocolateImage),
)

Gunakan Material dengan shadowColor di dalam Container seperti ini:

Container(
  decoration: BoxDecoration(
      borderRadius: BorderRadius.only(
          bottomLeft: Radius.circular(10),
          bottomRight: Radius.circular(10)),
      boxShadow: [
        BoxShadow(
            color: Color(0xffA22447).withOpacity(.05),
            offset: Offset(0, 0),
            blurRadius: 20,
            spreadRadius: 3)
      ]),
  child: Material(
    borderRadius: BorderRadius.only(
        bottomLeft: Radius.circular(10),
        bottomRight: Radius.circular(10)),
    elevation: 5,
    shadowColor: Color(0xffA22447).withOpacity(.05),
    color: Color(0xFFF7F7F7),
    child: SizedBox(
      height: MediaQuery.of(context).size.height / 3,
    ),
  ),
)

ini adalah bagaimana saya melakukannya

    Container(
  decoration: new BoxDecoration(
    boxShadow: [
      BoxShadow(
        color: Colors.grey[200],
        blurRadius: 2.0, // has the effect of softening the shadow
        spreadRadius: 2.0, // has the effect of extending the shadow
        offset: Offset(
          5.0, // horizontal, move right 10
          5.0, // vertical, move down 10
        ),
      )
    ],
  ),
  child: Container( 
       color: Colors.white, //in your example it's blue, pink etc..
       child: //your content
  )

Jawaban yang diberikan melakukan trik untuk bayangan luar yaitu di sekitar widget. Saya ingin bayangan pada widget yang ada di dalam batas dan menurut masalah github belum ada atribut inset di ShadowBox. Solusi saya adalah menambahkan lapisan widget dengan gradien menggunakan widget tumpukan sehingga tampak seperti widget itu sendiri memiliki bayangan. Anda harus menggunakan mediaQuery untuk dimensi, jika tidak tata letak akan kacau balau di perangkat yang berbeda. Berikut contoh kode untuk pemahaman yang lebih baik:

Stack(
            children: <Widget>[
              Container(
                decoration: BoxDecoration(
                  image: DecorationImage(
                    fit: BoxFit.cover,
                    image: AssetImage("assets/sampleFaces/makeup.jpeg"),
                    // fit: BoxFit.cover,
                  ),
                ),
                height: 350.0,
              ),
              Container(
                decoration: BoxDecoration(
                  gradient: LinearGradient(
                    begin: FractionalOffset.topCenter,
                    end: FractionalOffset.bottomCenter,
                    colors: [
                      Colors.black.withOpacity(0.0),
                      Colors.black54,
                    ],
                    stops: [0.95, 5.0],
                  ),
                ),
              )
            ],
          ),

class ShadowContainer extends StatelessWidget {
  ShadowContainer({
    Key key,
    this.margin = const EdgeInsets.fromLTRB(0, 10, 0, 8),
    this.padding = const EdgeInsets.symmetric(horizontal: 8),
    this.circular = 4,
    this.shadowColor = const Color.fromARGB(
        128, 158, 158, 158), //Colors.grey.withOpacity(0.5),
    this.backgroundColor = Colors.white,
    this.spreadRadius = 1,
    this.blurRadius = 3,
    this.offset = const Offset(0, 1),
    @required this.child,
  }) : super(key: key);

  final Widget child;
  final EdgeInsetsGeometry margin;
  final EdgeInsetsGeometry padding;
  final double circular;
  final Color shadowColor;
  final double spreadRadius;
  final double blurRadius;
  final Offset offset;
  final Color backgroundColor;

  @override
  Widget build(BuildContext context) {
    return Container(
      margin: margin,
      padding: padding,
      decoration: BoxDecoration(
        color: backgroundColor,
        borderRadius: BorderRadius.circular(circular),
        boxShadow: [
          BoxShadow(
            color: shadowColor,
            spreadRadius: spreadRadius,
            blurRadius: blurRadius,
            offset: offset,
          ),
        ],
      ),
      child: child,
    );
  }
}

Tambahkan bayangan kotak ke wadah di flutter

  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
          ),
        ],
      ),
  )

Ini keluaran saya