Develop Reference

Unexpected Line between Containers Flutter

Many Times in flutter I Found a Line between two Containers in flutter.
Code example
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
debugShowCheckedModeBanner: false,
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: const MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
final String title;
const MyHomePage({
Key? key,
required this.title,
}) : super(key: key);
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.white,
appBar: AppBar(
title: Text(widget.title),
),
body: SingleChildScrollView(
child: Column(
children: [
Container(
color: Colors.red,
width: double.infinity,
child: Column(
children: [
Container(
height: 150,
child: const Center(
child: Text('cdccd'),
),
),
Container(
height: 20,
color: Colors.red,
),
buildSeperator()
],
),
),
Container(
height: 300,
width: double.infinity,
child: Text('cdcdcd'),
),
],
),
),
);
}
///Build Seperator
Widget buildSeperator() {
return Stack(
children: [
Container(
height: 24,
color: Colors.red,
),
Container(
decoration: const BoxDecoration(
borderRadius: BorderRadius.only(
topLeft: Radius.circular(50),
topRight: Radius.circular(50),
),
color: Colors.white,
),
height: 24,
width: double.infinity,
),
],
);
}
}
Reference Image:
If It's a Flutter Issue: Flutter Team Request you to Resolve it.

Work Around but not final Solution,
Add Another Container Above the Container with a border with a higher height.
class _MyHomePageState extends State<MyHomePage> {
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.white,
appBar: AppBar(
elevation: 0,
backgroundColor: Color(0xFF842247),
title: Text(widget.title),
),
body: SingleChildScrollView(
child: Column(
children: [
Container(
color: const Color(0xFF842247),
height: 56,
),
Container(
color: const Color(0xFF842247),
width: double.infinity,
child: Column(
children: [
Container(
height: 24,
child: const Center(
child: Text('cdccd'),
),
),
buildSeperator()
],
),
),
Container(
height: 300,
// width: double.infinity,
child: Text('cdcdcd'),
),
],
),
),
);
}
///Build Seperator
Widget buildSeperator() {
return Stack(
clipBehavior: Clip.none,
children: [
Container(
height: 24,
color: const Color(0xFF842247),
),
Container(
decoration: const BoxDecoration(
borderRadius: BorderRadius.only(
topLeft: Radius.circular(50),
topRight: Radius.circular(50),
),
color: Colors.white,
),
height: 24,
width: double.infinity,
),
],
);
}
}

FLUTTER - A RenderFlex overflowed by 126 pixels on the right

please help me, i have a errpr in my code like this , "A RenderFlex overflowed by 126 pixels on the right". and this is my code.
I've searched the internet that most solutions use flexible, but I'm still confused where to place it. I want when the text increases, the height of the box also increases
ListView.builder(
itemCount: 5,
padding: EdgeInsets.only(left: 16, right: 16),
shrinkWrap: true,
itemBuilder: (context, index) {
return Container(
height: 76,
margin: EdgeInsets.only(bottom: 13),
padding:
EdgeInsets.only(left: 24, top: 12, bottom: 12, right: 22),
decoration: BoxDecoration(
color: Color(0xFFFFFFFF),
borderRadius: BorderRadius.circular(15),
boxShadow: [
BoxShadow(
offset: Offset(0, 10),
blurRadius: 50,
color: kPrimaryColor.withOpacity(0.23))
]),
child: Row(
children: <Widget>[
Row(
children: <Widget>[
Container(
height: 57,
width: 57,
decoration: BoxDecoration(
shape: BoxShape.circle,
image: DecorationImage(
image: AssetImage(
"assets/images/image_1.png"))),
),
SizedBox(
width: 13,
),
Text(
"testing123451 testing123451 testing123451 testing123451",
),
],
)
],
),
);
})
please give me the solution, thank you

At first remove row's parent Row widget and wrap Text widget with Expanded.
import 'package:flutter/material.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
visualDensity: VisualDensity.adaptivePlatformDensity,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
#override
void initState() {
super.initState();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: _buildBody(),
floatingActionButton: FloatingActionButton(
onPressed: () {},
tooltip: 'Increment',
child: Icon(Icons.add),
),
);
}
Widget _buildBody() {
return ListView.builder(
itemCount: 5,
padding: EdgeInsets.only(left: 16, right: 16),
shrinkWrap: true,
itemBuilder: (context, index) {
return Container(
// height: 76,
margin: EdgeInsets.only(bottom: 13),
padding: EdgeInsets.only(left: 24, top: 12, bottom: 12, right: 22),
decoration: BoxDecoration(
color: Color(0xFFFFFFFF),
borderRadius: BorderRadius.circular(15),
boxShadow: [
BoxShadow(
offset: Offset(0, 10),
blurRadius: 50,
color: Colors.blue.withOpacity(0.23))
]),
child: Row(
children: <Widget>[
Container(
height: 57,
width: 57,
decoration: BoxDecoration(
shape: BoxShape.circle,
image: DecorationImage(
image: AssetImage("assets/images/image_1.png"))),
),
SizedBox(
width: 13,
),
Expanded(
child: Text(
"testing123451 testing123451 testing123451 testing123451",
),
),
],
),
);
});
}
}

You could use the Expanded widget and wrap it around the Text widget, like this:
Expanded(
child: Text(
"testing123451 testing123451 testing123451 testing123451"
)
),

flutter - curved_navigation_bar setting navigation page

good afternoon, i'm new in flutter, i'm trying to use curved_navigation_bar, but i'm confused how to set the page navigation, this is my code, index 0 will go to news.dart page, index 1 will go to cells.dart page, index 2 will go to home.dart page, index 3 goes to book.dart page,
index 4 goes to info.dart page,
The first page that appears is index 2, thank you
import 'package:curved_navigation_bar/curved_navigation_bar.dart';
import 'package:flutter/material.dart';
import 'package:flutter_svg/flutter_svg.dart';
import 'package:statistik_malang/body.dart';
import 'package:statistik_malang/constants.dart';
class HomeScreen extends StatefulWidget {
// const HomeScreen({ Key? key }) : super(key: key);
#override
_HomeScreenState createState() => _HomeScreenState();
}
class _HomeScreenState extends State<HomeScreen> {
#override
Widget build(BuildContext context) {
return Scaffold(
// appBar: AppBar(),
body: Body(),
extendBody: true,
bottomNavigationBar: CurvedNavigationBar(
backgroundColor: Colors.transparent,
buttonBackgroundColor: kPrimaryColor,
animationDuration: Duration(milliseconds: 300),
height: 50,
items: <Widget>[
SvgPicture.asset(
"assets/icons/news.svg",
width: 20.0,
height: 20.0,
),
SvgPicture.asset(
"assets/icons/cells.svg",
width: 20.0,
height: 20.0,
),
SvgPicture.asset(
"assets/icons/home.svg",
width: 20.0,
height: 20.0,
),
SvgPicture.asset(
"assets/icons/book.svg",
width: 20.0,
height: 20.0,
),
SvgPicture.asset(
"assets/icons/information.svg",
width: 20.0,
height: 20.0,
),
],
onTap: (index) {},
),
);
}
}

Just add navigationKey and start index with 0, it will be solved
Edited:
class _HomeScreenState extends State<HomeScreen> {
int _page = 0;
GlobalKey<CurvedNavigationBarState> _bottomNavigationKey = GlobalKey();
#override
Widget build(BuildContext context) {
return Scaffold(
// appBar: AppBar(),
body: Container(
color: Colors.blueAccent,
child: Center(
child: Column(
children: <Widget>[
Text(_page.toString(), textScaleFactor: 10.0),
],
),
)),
extendBody: true,
bottomNavigationBar: CurvedNavigationBar(
key: _bottomNavigationKey,
backgroundColor: Colors.transparent,
// buttonBackgroundColor: kPrimaryColor,
animationDuration: Duration(milliseconds: 300),
height: 50,
index: 0,
items: <Widget>[
SvgPicture.asset(
"assets/icons/news.svg",
width: 20.0,
height: 20.0,
),
SvgPicture.asset(
"assets/icons/cells.svg",
width: 20.0,
height: 20.0,
),
SvgPicture.asset(
"assets/icons/home.svg",
width: 20.0,
height: 20.0,
),
SvgPicture.asset(
"assets/icons/book.svg",
width: 20.0,
height: 20.0,
),
SvgPicture.asset(
"assets/icons/information.svg",
width: 20.0,
height: 20.0,
),
],
onTap: (index) {
setState(() {
_page = index;
});
},
),
);
}
}

Is it possible to implement widgets using list in flutter?

I am creating a Journal mobile application which would work as a medium to view magazines and daily news updates. This is my first flutter project and I am totally new to flutter. So kindly excuse me if I had said something wrong about something or didnt provide enough information.
I used a code from github for the main page of my application and made few changes to accommodate my needs. Now in my code, the home page consists of a side menu bar and this bar consists of 4 buttons, namely Home, My Profile, Premium and FAQ. The GlobalKeys for the side menu bar is called using a list by the name _keys which is of the type GlobalKey. I tried changing the data type of the list _keys to Widget and then called the corresponding Widgets of the classes. But then two errors popped out.
The getter 'currentContext' isn't defined for the class 'Widget'.
The argument type 'Widget' can't be assigned to the parameter type 'GlobalKey<State>'.
Now I would like the list _keys to be of the type Widget in order for me to call upon it's corresponding widgets of Home, My Profile, Premium and FAQ from each of it's classes in order for me to view the corresponding pages. Or if it is not possible, I would love to know an alternative for it to start working.
Following is the code of my application.
import 'dart:math' as math;
import 'package:flutter/scheduler.dart';
import 'package:google_signin_example/google%20sign%20in/logged_in_widget.dart';
import 'package:google_signin_example/main app/lib/ui_3/TravelBean.dart';
import 'package:google_signin_example/main app/lib/ui_3/magazine/screens/home_screen.dart';
import 'package:google_signin_example/main%20app/lib/ui_3/FAQ/faq.dart';
import 'package:google_signin_example/main%20app/lib/ui_3/Newspaper%20and%20Kiddos/lib_kiddos/main.dart';
import 'package:google_signin_example/main%20app/lib/ui_3/Newspaper%20and%20Kiddos/lib_news/main.dart';
import 'package:google_signin_example/main%20app/lib/ui_3/premium/premium.dart';
import 'package:google_signin_example/widget/sign_up_widget.dart';
import 'detail_page.dart';
class HomePage1 extends StatefulWidget {
#override
_HomePage1State createState() => _HomePage1State();
}
class _HomePage1State extends State<HomePage1> {
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.white,
body: Container(
child: Row(
children: <Widget>[
LeftWidget(),
Expanded(
child: RightWidget(),
)
],
),
),
);
}
}
class LeftWidget extends StatefulWidget {
#override
_LeftWidgetState createState() => _LeftWidgetState();
}
class _LeftWidgetState extends State<LeftWidget> with TickerProviderStateMixin {
List<String> _list = ["Home", "My profile", "Premium", "FAQ"];
List <Widget> _keys = [
HomePage1(), //These are the widgets from different classes.
LoggedInWidget(),
premium(),
faq(),
/*GlobalKey(), //This was available before I made the changes.
GlobalKey(),
GlobalKey(),
GlobalKey()*/
];
int checkIndex = 0;
Offset checkedPositionOffset = Offset(0, 0);
Offset lastCheckOffset = Offset(0, 0);
Offset animationOffset = Offset(0, 0);
Animation _animation;
AnimationController _animationController;
#override
void initState() {
checkIndex = _list.length - 1;
super.initState();
SchedulerBinding.instance.endOfFrame.then((value) {
calcuteCheckOffset();
addAnimation();
});
}
void calcuteCheckOffset() {
lastCheckOffset = checkedPositionOffset;
RenderBox renderBox = _keys[checkIndex].currentContext.findRenderObject(); //This is where the first error occurs.
Offset widgetOffset = renderBox.localToGlobal(Offset(0, 0));
Size widgetSise = renderBox.size;
checkedPositionOffset = Offset(widgetOffset.dx + widgetSise.width,
widgetOffset.dy + widgetSise.height);
}
#override
Widget build(BuildContext context) {
return Container(
child: Stack(
children: <Widget>[
Container(
width: 50,
decoration: BoxDecoration(
color: Color(0xff000000),
borderRadius: BorderRadius.circular(30),
),
child: Column(
children: _buildList(),
),
),
Positioned(
top: animationOffset.dy,
left: animationOffset.dx,
child: CustomPaint(
painter: CheckPointPainter(Offset(10, 0)),
),
)
],
),
);
}
List<Widget> _buildList() {
List<Widget> _widget_list = [];
_widget_list.add(Padding(
padding: EdgeInsets.only(
top: 50,
),
child: Icon(
Icons.settings,
color: Colors.white,
size: 30,
),
));
for (int i = 0; i < _list.length; i++) {
_widget_list.add(Expanded(
child: GestureDetector(
onTap: () {
indexChecked(i);
},
child: VerticalText(
_list[i],
_keys[i], //This is where the second error occurs.
checkIndex == i &&
(_animationController != null &&
_animationController.isCompleted))),
));
}
_widget_list.add(Padding(
padding: EdgeInsets.only(
top: 50,
bottom: 50,
),
child: Image(image: AssetImage('assets/images/Voix.png')),
));
return _widget_list;
}
void indexChecked(int i) {
if (checkIndex == i) return;
setState(() {
checkIndex = i;
calcuteCheckOffset();
addAnimation();
});
}
void addAnimation() {
_animationController =
AnimationController(duration: Duration(milliseconds: 300), vsync: this)
..addListener(() {
setState(() {
animationOffset =
Offset(checkedPositionOffset.dx, _animation.value);
});
});
_animation = Tween(begin: lastCheckOffset.dy, end: checkedPositionOffset.dy)
.animate(CurvedAnimation(
parent: _animationController, curve: Curves.easeInOutBack));
_animationController.forward();
}
}
class CheckPointPainter extends CustomPainter {
double pointRadius = 5;
double radius = 30;
Offset offset;
CheckPointPainter(this.offset);
#override
void paint(Canvas canvas, Size size) {
Paint paint = Paint()..style = PaintingStyle.fill;
double startAngle = -math.pi / 2;
double sweepAngle = math.pi;
paint.color = Color(0xff000000);
canvas.drawArc(
Rect.fromCircle(center: Offset(offset.dx, offset.dy), radius: radius),
startAngle,
sweepAngle,
false,
paint);
paint.color = Color(0xffffffff);
canvas.drawCircle(
Offset(offset.dx - pointRadius / 2, offset.dy - pointRadius / 2),
pointRadius,
paint);
}
#override
bool shouldRepaint(CustomPainter oldDelegate) {
return true;
}
}
class VerticalText extends StatelessWidget {
String name;
bool checked;
GlobalKey globalKey;
VerticalText(this.name, this.globalKey, this.checked);
#override
Widget build(BuildContext context) {
return RotatedBox(
key: globalKey,
quarterTurns: 3,
child: Text(
name,
style: TextStyle(
color: checked ? Color(0xffffffff) : Colors.grey,
fontSize: 16,
),
),
);
}
}
class RightWidget extends StatefulWidget {
#override
_RightWidgetState createState() => _RightWidgetState();
}
class _RightWidgetState extends State<RightWidget>
with TickerProviderStateMixin {
TabController _tabController;
#override
void initState() {
super.initState();
_tabController = TabController(vsync: this, length: 5);
}
#override
Widget build(BuildContext context) {
return Container(
margin: EdgeInsets.only(
left: 15,
),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Padding(
padding: EdgeInsets.only(top: 50, left: 20),
child: Text(
"Voix Home",
style: TextStyle(
color: Colors.black,
fontSize: 25,
),
),
),
Padding(
padding: const EdgeInsets.only(top: 15, left: 10),
child: SizedBox(
height: 30,
child: TabBar(
isScrollable: true,
unselectedLabelColor: Colors.black,
labelColor: Color(0xffffffff),
controller: _tabController,
indicator: BoxDecoration(
color: Color(0xff9e9e9e),
borderRadius: BorderRadius.only(
topRight: Radius.circular(20),
bottomLeft: Radius.circular(20),
),
),
tabs: <Widget>[
Tab(
text: "Flash",
),
Tab(
text: "Magazine",
),
Tab(
text: "Newspaper",
),
Tab(
text: "Kiddos",
),
Tab(
text: "Editorial",
),
],
),
),
),
Expanded(
child: TabBarView(
controller: _tabController,
children: <Widget>[
TravelWidget(),
HomeScreen(),
News(),
Kiddos(),
RightBody(),
// RightBody(),
],
),
)
],
),
);
}
}
class RightBody extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Container(
margin: EdgeInsets.only(
left: 15,
),
color: Colors.white,
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Padding(
padding: EdgeInsets.only(
top: 20,
),
child: Text(
"Flash!",
style: TextStyle(
color: Colors.black,
fontSize: 20,
),
),
),
Expanded(
child: ListView(
scrollDirection: Axis.horizontal,
children: <Widget>[
Container(
width: 220,
margin: EdgeInsets.symmetric(
horizontal: 10,
vertical: 10,
),
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(40),
image: new DecorationImage(
image: new AssetImage('assets/images/bottom1.jpg'),
fit: BoxFit.cover,
),
boxShadow: [
BoxShadow(
spreadRadius: 5,
blurRadius: 5,
offset: Offset(1, 2),
color: Color(0x33757575),
),
],
),
),
Container(
width: 220,
margin: EdgeInsets.symmetric(
horizontal: 10,
vertical: 10,
),
decoration: BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.circular(40),
boxShadow: [
BoxShadow(
spreadRadius: 5,
blurRadius: 5,
offset: Offset(1, 2),
color: Color(0x33757575),
),
],
),
),
],
),
),
],
),
);
}
}
class TravelWidget extends StatelessWidget {
List<TravelBean> _list = TravelBean.generateTravelBean();
#override
Widget build(BuildContext context) {
return PageView.builder(
controller: PageController(viewportFraction: 0.9),
itemBuilder: (context, index) {
var bean = _list[index];
return GestureDetector(
onTap: () {
Navigator.of(context).push(MaterialPageRoute(builder: (context) {
return DetailPage(bean);
}));
},
child: Hero(
tag: bean.url,
child: Stack(
children: <Widget>[
Padding(
padding: const EdgeInsets.only(bottom: 30, right: 10),
child: ClipRRect(
borderRadius: BorderRadius.circular(5),
child: Image.asset(
bean.url,
width: MediaQuery.of(context).size.width,
fit: BoxFit.cover,
),
),
),
Positioned(
bottom: 80,
left: 15,
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Material(
color: Colors.transparent,
child: Text(
bean.location,
style: TextStyle(
color: Colors.black54,
fontSize: 15,
),
),
),
Material(
color: Colors.transparent,
child: Text(
bean.name,
style: TextStyle(
color: Colors.black,
fontSize: 20,
),
),
),
],
),
),
Positioned(
bottom: 0,
right: 30,
child: Container(
width: 60,
height: 60,
decoration: BoxDecoration(
color: Colors.black,
borderRadius: BorderRadius.circular(30),
),
child: Icon(
Icons.arrow_forward,
color: Colors.white,
size: 30,
),
),
)
],
),
),
);
},
itemCount: _list.length,
);
}
}
At the beginning, when I leave the list _keys to be of the type GlobalKey and don't comment out the following 4 GlobalKeys I get the output but the side menu bar won't work.
This is my application with GlobalKeys in place of those Widgets
I want those corresponding pages to display when clicked on. But that render object just switches between the options and the same page is displayed.
So kindly help me out.
PS : As said earlier I'm new to flutter, so kindly don't mistake me if I had something wrong.

I suggest you check about flutter state management, especially Mobx with Provider, it will be kind easier for you.

Flutter shadow over other widgets

My base widget is a Column. The first element is a Container which has a BoxShadow. The second element is a ListView which builds several Card, depending on the context. If the scroll is 0 the shadow gets displayed. However when start scrolling, the card is "over" the shadow (higher z-index) and hides it.
unscrolled
scrolled
The shadow should stay always on top, over the Cards. How is this done?

EDIT
if you don't want container shadow to disappear on scroll remove the ScrollNotification and NotificationListener
There is a widget for that 😉
You can use ScrollNotification with NotificationListener. Try this;
Happy coding! 🤓
class TestPage extends StatefulWidget {
const TestPage({Key key}) : super(key: key);
#override
_TestPageState createState() => _TestPageState();
}
class _TestPageState extends State<TestPage> {
double blurRadius = 10.0;
double spreadRadius = 1.0;
#override
void initState() {
super.initState();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.blueGrey,
title: Text('Title'),
),
body: Container(
width: Get.width,
height: Get.height,
child: Stack(
children: [
Padding(
padding: const EdgeInsets.symmetric(horizontal: 16.0).copyWith(
top: 62.0,
),
child: NotificationListener<ScrollNotification>(
// ignore: missing_return
onNotification: (scrollNotification) {
if (scrollNotification is ScrollStartNotification) {
setState(() {
blurRadius = 0.0;
spreadRadius = 0.0;
});
} else if (scrollNotification is ScrollEndNotification) {
setState(() {
blurRadius = 10.0;
spreadRadius = 1.0;
});
}
},
child: ListView.builder(
// controller: _controller,
itemCount: 10,
itemBuilder: (context, index) {
return Card(
child: Container(
width: Get.width * .8,
height: 100.0,
child: Center(
child: Text('child # index : $index'),
)),
);
},
),
),
),
Positioned(
top: 0,
left: 0,
right: 0,
child: Container(
width: Get.width,
height: 60.0,
margin: EdgeInsets.only(),
decoration: BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.only(
bottomLeft: Radius.circular(20.0),
bottomRight: Radius.circular(20.0),
),
boxShadow: [
BoxShadow(
color: Colors.grey,
blurRadius: blurRadius,
spreadRadius: spreadRadius,
),
],
),
child: Center(
child: Text('TOP CONTAINER'),
),
),
),
],
),
),
);
}
}

According to your question, here is the concept of what is going wrong here.
The 1st child of Column is a Container with shadow. Shadow renders outside of the defined size. If you don't provide any spaces after this Container we won't be able to see the shadow. This space can be done by Container margin , SizedBox or wrapping our list with Padding. But now our main question is how we get shadow while index=0. I believe it is coming from ListChildren`. They contain upper spaces, that's why we can see only the 1st time.
On Ui render priority starts from bottom to Top.
How to solve this problem:
We can provide space at the bottom of our container or assign margin(not padding), or use a SizedBox after the container providing the same amount of height as shadow.
providing bottom margin on the container.
adding a SizedBox with height of shadow.
wrapping our list with Padding and providing top:.
In this image,
our shadow: white, background:amber.
Demo code:
import 'package:flutter/material.dart';
class ColumnWithContainerShadow extends StatelessWidget {
const ColumnWithContainerShadow({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.amber,
body: Column(
children: [
Container(
height: 50,
width: double.infinity,
////* we dont need margin if we have padding on ListView
// margin: EdgeInsets.only(bottom: 12),
decoration: BoxDecoration(
color: Colors.green,
boxShadow: [
BoxShadow(
offset: Offset(0, 12),
color: Colors.white,
)
],
),
child: Center(child: Text("Container A")),
),
Expanded(
child: Padding(
padding: const EdgeInsets.only(top: 12),
child: ListView(
children: [
...List.generate(
333,
(index) => Container(
/// enable this margine and remove other spaces to see 1st child shadow.(shadow depend on children position)
// margin: EdgeInsets.only(top: 12),
height: 60,
color: Colors.deepPurple,
child: Text("$index"),
),
)
],
),
),
),
Container(
height: 50,
width: double.infinity,
alignment: Alignment.center,
decoration: BoxDecoration(
color: Colors.green,
boxShadow: [
BoxShadow(
offset: Offset(0, 12),
color: Colors.white,
)
],
),
child: Text("Bottom Container"),
),
// Comment to close shadow
SizedBox(
height: 20,
)
],
),
);
}
}

Wrap this upper box in Material widget and provide an elevation.