BottomNavigationBar
sample.packages.flutter.lib.src.material.bottom_navigation_bar.109.
This example shows a [BottomNavigationBar] as it is used within a [Scaffold]
widget. The [BottomNavigationBar] has four [BottomNavigationBarItem]
widgets, which means it defaults to [BottomNavigationBarType.shifting], and
the [currentIndex] is set to index 0. The selected item is amber in color.
With each [BottomNavigationBarItem] widget, backgroundColor property is
also defined, which changes the background color of [BottomNavigationBar],
when that item is selected. The _onItemTapped
function changes the
selected item's index and displays a corresponding message in the center of
the [Scaffold].
import 'package:flutter/material.dart';
void main() => runApp(const MyApp());
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
static const String _title = 'Flutter Code Sample';
@override
Widget build(BuildContext context) {
return const MaterialApp(
title: _title,
home: MyStatefulWidget(),
);
}
}
class MyStatefulWidget extends StatefulWidget {
const MyStatefulWidget({Key? key}) : super(key: key);
@override
State createState() => _MyStatefulWidgetState();
}
class _MyStatefulWidgetState extends State {
int _selectedIndex = 0;
static const TextStyle optionStyle =
TextStyle(fontSize: 30, fontWeight: FontWeight.bold);
static const List _widgetOptions = [
Text(
'Index 0: Home',
style: optionStyle,
),
Text(
'Index 1: Business',
style: optionStyle,
),
Text(
'Index 2: School',
style: optionStyle,
),
Text(
'Index 3: Settings',
style: optionStyle,
),
];
void _onItemTapped(int index) {
setState(() {
_selectedIndex = index;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('BottomNavigationBar Sample'),
),
body: Center(
child: _widgetOptions.elementAt(_selectedIndex),
),
bottomNavigationBar: BottomNavigationBar(
items: const [
BottomNavigationBarItem(
icon: Icon(Icons.home),
label: 'Home',
backgroundColor: Colors.red,
),
BottomNavigationBarItem(
icon: Icon(Icons.business),
label: 'Business',
backgroundColor: Colors.green,
),
BottomNavigationBarItem(
icon: Icon(Icons.school),
label: 'School',
backgroundColor: Colors.purple,
),
BottomNavigationBarItem(
icon: Icon(Icons.settings),
label: 'Settings',
backgroundColor: Colors.pink,
),
],
currentIndex: _selectedIndex,
selectedItemColor: Colors.amber[800],
onTap: _onItemTapped,
),
);
}
}
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