How to programmatically select BottomNavigationBar Tab in Flutter instead of built in onTap callback?
You can grab this BottomNavigationBar widget by using a GlobalKey. By this GlobalKey you can handle this widget. Here is an gist for the code
Here you assign a GlobalKey
GlobalKey globalKey = new GlobalKey(debugLabel: 'btm_app_bar');
And put that key in your BottomNavigationBar
new BottomNavigationBar(
key: globalKey,
items: [...],
onTap: (int index) {...},
),
Now you can call widget's method and use CurvedNavigationBar instead of BottomNavigationBar if you have to work with CurvedNavigationBar.
final BottomNavigationBar navigationBar = globalKey.currentWidget;
navigationBar.onTap(2);
Here is a complete example on how to achieve what you want.
import 'package:flutter/material.dart';
void main() => runApp(new MyApp());
const String page1 = "Page 1";
const String page2 = "Page 2";
const String page3 = "Page 3";
const String title = "BNB Demo";
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return new MaterialApp(
title: title,
home: new MyHomePage(title: title),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
@override
_MyHomePageState createState() => new _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
List<Widget> _pages;
Widget _page1;
Widget _page2;
Widget _page3;
int _currentIndex;
Widget _currentPage;
@override
void initState() {
super.initState();
_page1 = Page1();
_page2 = Page2();
_page3 = Page3();
_pages = [_page1, _page2, _page3];
_currentIndex = 0;
_currentPage = _page1;
}
void changeTab(int index) {
setState(() {
_currentIndex = index;
_currentPage = _pages[index];
});
}
@override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(
title: new Text(widget.title),
),
body: _currentPage,
bottomNavigationBar: BottomNavigationBar(
onTap: (index) => changeTab(index),
currentIndex: _currentIndex,
items: [
BottomNavigationBarItem(
title: Text(page1), icon: Icon(Icons.account_circle)),
BottomNavigationBarItem(
title: Text(page2), icon: Icon(Icons.account_circle)),
BottomNavigationBarItem(
title: Text(page3), icon: Icon(Icons.account_circle))
]),
drawer: new Drawer(
child: new Container(
margin: EdgeInsets.only(top: 20.0),
child: new Column(
children: <Widget>[
navigationItemListTitle(page1, 0),
navigationItemListTitle(page2, 1),
navigationItemListTitle(page3, 2),
],
),
),
),
);
}
Widget navigationItemListTitle(String title, int index) {
return new ListTile(
title: new Text(
title,
style: new TextStyle(color: Colors.blue[400], fontSize: 22.0),
),
onTap: () {
Navigator.pop(context);
changeTab(index);
},
);
}
}
class Page1 extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Center(
child: Text(page1),
);
}
}
class Page2 extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Center(
child: Text(page2),
);
}
}
class Page3 extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Center(
child: Text(page3),
);
}
}
whenever you want to change to a tab, call the changeTab(YOUR_TAB_INDEX)