Display different fab depending on active View of TabBarView - flutter

Question

If PageA is selected, fabA should be displayed. If PageB is selected, fabB respectively.
Whats the best way to achieve this?
var fabA = FloatingActionButton();
var fabB = FloatingActionButton();
...
Scaffold(
body: TabBarView(children: [
PageA(),
PageB(),
]),
floatingActionButton: fabA,
)

Answer 1

You can copy paste run full code below
You can declare a List<FloatingActionButton> and return based on tabController.index
code snippet
_tabController = TabController(vsync: this, length: choices.length)
..addListener(() {
if (_tabController.indexIsChanging) {
print(
"tab is animating. from active (getting the index) to inactive(getting the index) ");
} else {
setState(() {});
...
floatingActionButton: floatButton[_tabController.index],
...
List<FloatingActionButton> floatButton = [
FloatingActionButton(
onPressed: () {
// Add your onPressed code here!
},
child: Icon(Icons.navigation),
backgroundColor: Colors.green,
),
FloatingActionButton(
onPressed: () {
// Add your onPressed code here!
},
child: Icon(Icons.share),
backgroundColor: Colors.green,
),
working demo
full code
import 'package:flutter/material.dart';
class AppBarBottomSample extends StatefulWidget {
#override
_AppBarBottomSampleState createState() => _AppBarBottomSampleState();
}
class _AppBarBottomSampleState extends State<AppBarBottomSample>
with SingleTickerProviderStateMixin {
TabController _tabController;
#override
void initState() {
super.initState();
_tabController = TabController(vsync: this, length: choices.length)
..addListener(() {
if (_tabController.indexIsChanging) {
print(
"tab is animating. from active (getting the index) to inactive(getting the index) ");
} else {
//tab is finished animating you get the current index
//here you can get your index or run some method once.
print(_tabController.index);
setState(() {});
}
});
}
#override
void dispose() {
_tabController.dispose();
super.dispose();
}
void _nextPage(int delta) {
final int newIndex = _tabController.index + delta;
if (newIndex < 0 || newIndex >= _tabController.length) return;
_tabController.animateTo(newIndex);
}
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: const Text('AppBar Bottom Widget'),
leading: IconButton(
tooltip: 'Previous choice',
icon: const Icon(Icons.arrow_back),
onPressed: () {
_nextPage(-1);
},
),
actions: <Widget>[
IconButton(
icon: const Icon(Icons.arrow_forward),
tooltip: 'Next choice',
onPressed: () {
_nextPage(1);
},
),
],
bottom: PreferredSize(
preferredSize: const Size.fromHeight(48.0),
child: Theme(
data: Theme.of(context).copyWith(accentColor: Colors.white),
child: Container(
height: 48.0,
alignment: Alignment.center,
child: TabPageSelector(controller: _tabController),
),
),
),
),
body: TabBarView(
controller: _tabController,
children: choices.map((Choice choice) {
return Padding(
padding: const EdgeInsets.all(16.0),
child: ChoiceCard(choice: choice),
);
}).toList(),
),
floatingActionButton: floatButton[_tabController.index],
),
);
}
}
List<FloatingActionButton> floatButton = [
FloatingActionButton(
onPressed: () {
// Add your onPressed code here!
},
child: Icon(Icons.navigation),
backgroundColor: Colors.green,
),
FloatingActionButton(
onPressed: () {
// Add your onPressed code here!
},
child: Icon(Icons.share),
backgroundColor: Colors.green,
),
FloatingActionButton(
onPressed: () {
// Add your onPressed code here!
},
child: Icon(Icons.create),
backgroundColor: Colors.green,
),
FloatingActionButton(
onPressed: () {
// Add your onPressed code here!
},
child: Icon(Icons.repeat),
backgroundColor: Colors.green,
),
FloatingActionButton(
onPressed: () {
// Add your onPressed code here!
},
child: Icon(Icons.forward),
backgroundColor: Colors.green,
),
FloatingActionButton(
onPressed: () {
// Add your onPressed code here!
},
child: Icon(Icons.link),
backgroundColor: Colors.green,
)
];
class Choice {
const Choice({this.title, this.icon});
final String title;
final IconData icon;
}
const List<Choice> choices = const <Choice>[
const Choice(title: 'CAR', icon: Icons.directions_car),
const Choice(title: 'BICYCLE', icon: Icons.directions_bike),
const Choice(title: 'BOAT', icon: Icons.directions_boat),
const Choice(title: 'BUS', icon: Icons.directions_bus),
const Choice(title: 'TRAIN', icon: Icons.directions_railway),
const Choice(title: 'WALK', icon: Icons.directions_walk),
];
class ChoiceCard extends StatelessWidget {
const ChoiceCard({Key key, this.choice}) : super(key: key);
final Choice choice;
#override
Widget build(BuildContext context) {
final TextStyle textStyle = Theme.of(context).textTheme.display1;
return Card(
color: Colors.white,
child: Center(
child: Column(
mainAxisSize: MainAxisSize.min,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
Icon(choice.icon, size: 128.0, color: textStyle.color),
Text(choice.title, style: textStyle),
],
),
),
);
}
}
void main() {
runApp(AppBarBottomSample());
}