Flutter add a black outline to top of BottomNavigationBar - flutter

Question

I am trying to figure out how to add a very subtle black line to the top of a BottomNavigationBar to make it's start more distinct from the rest of the content. AirBnb would be a good example of this.
Is there a way to achieve this with Flutter?
Below is the widget I am currently using to render the BottomNavigationBar and I have attached a sample below where there is a distinct grey line at the top of the navbar for AirBnb.
#override
Widget build(BuildContext context) {
return Scaffold(
body: currentPage,
bottomNavigationBar: PreferredSize(
preferredSize: Size.fromHeight(50),
child: Container (
decoration: BoxDecoration(
border: Border.all(color: Colors.black)
),
)
),
);
}
The parent of this Widget:
void main() => runApp(MaterialApp(
home: new MyApp(),
debugShowCheckedModeBanner: true,
));
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Navbar();
}
}

Answer 1

How to add line on top of bottom navigation view in flutter ?
Code
class BottomNavigationBarHandler {
Widget bar(int currentIndex) {
return Container(
decoration: BoxDecoration(
color: Colors.white,
border: Border(top: BorderSide(color: Colors.white, width: 3.0))),
child: BottomNavigationBar(
backgroundColor: Colors.black,
selectedItemColor: Colors.pinkAccent,
unselectedItemColor: Colors.white,
showSelectedLabels: false,
showUnselectedLabels: false,
onTap: onTabTapped,
currentIndex: currentIndex,
items: [
BottomNavigationBarItem(
icon: Icon(Icons.home_outlined),
title: Text('Home')),
BottomNavigationBarItem(
icon: Icon(Icons.search),
title: Text('Messages')),
BottomNavigationBarItem(
icon: Icon(Icons.add),
title: Text('Profile'))]));
}
void onTabTapped(int index) {
print('BottomNavigationBarIndex ::' + index.toString());
}
}
Output

Answer 2

Widget build(BuildContext context) {
return Scaffold(
appBar: PreferredSize(
preferredSize: Size.fromHeight(200),
child: Container(
alignment: Alignment.center,
color: globals.white,
height: 100,
child: Text('imyadunandan'),
),
),
body: Container(
color: globals.white,
),
bottomNavigationBar: Container(
decoration: BoxDecoration(
color: globals.white,
boxShadow: [
BoxShadow(
color: globals.black,
),
],
),
child: BottomNavigationBar(
items: [
BottomNavigationBarItem(
icon: Icon(Icons.android),
title: Text('Android'),
),
BottomNavigationBarItem(
icon: Icon(Icons.desktop_windows),
title: Text('Windows'),
),
],
backgroundColor: globals.white,
elevation: 0,
),
),
);
}
this code achieves the fallowing