How can I show/hide a floatingActionButton in one tab to another? - flutter

Question

I was wondering how can I show/hide a FloatingActionButton in a TabBarView.
So for example in my first tab, I wanna a FloatingActionButton, but in the second tab I wanna hide it.
So in my case my code is:
class Notifications extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.white,
floatingActionButton: FloatingActionButton(
backgroundColor: kPink,
child: Icon(Icons.add),
onPressed: () => print(Localizations.localeOf(context)),
),
body: SafeArea(
child: Padding(
padding: const EdgeInsets.only(top: kBigSeparation),
child: DefaultTabController(
length: 2,
initialIndex: 0,
child: Padding(
padding: kPaddingTabBar,
child: Column(
children: <Widget>[
Container(
padding: EdgeInsets.all(kTinySeparation),
decoration: BoxDecoration(
color: kLightGrey,
borderRadius: BorderRadius.all(
Radius.circular(50),
),
),
child: TabBar(
tabs: <Tab>[
Tab(
text: AppLocalizations.of(context)
.translate('messages'),
),
Tab(
text: AppLocalizations.of(context)
.translate('notifications'),
)
],
unselectedLabelColor: Colors.black54,
labelColor: Colors.black,
unselectedLabelStyle: kBoldText,
labelStyle: kBoldText,
indicatorSize: TabBarIndicatorSize.tab,
indicator: BoxDecoration(
shape: BoxShape.rectangle,
borderRadius: BorderRadius.circular(50),
color: Colors.white,
),
),
),
const SizedBox(height: kMediumSeparation),
Expanded(
child: TabBarView(children: [
MessagesTab(),
NotificationsTab(),
]),
),
],
),
),
),
),
),
);
}
}

Answer 1

You can copy paste run full code below
Step 1 : You need to use TabController
Step 2 : Show/hide floatingActionButton based on tabIndex
code snippet
TabBar(
controller: _tabController,
tabs: <Tab>[
...
floatingActionButton: _tabController.index == 0
? FloatingActionButton(
backgroundColor: Colors.pink,
child: Icon(Icons.add),
onPressed: () => print(Localizations.localeOf(context)),
)
: Container(),
working demo
full code
import 'package:flutter/material.dart';
class Notifications extends StatefulWidget {
#override
_NotificationsState createState() => _NotificationsState();
}
class _NotificationsState extends State<Notifications>
with SingleTickerProviderStateMixin {
TabController _tabController;
#override
void initState() {
super.initState();
_tabController = TabController(length: 2, vsync: this, initialIndex: 0);
_tabController.addListener(_switchTabIndex);
}
void _switchTabIndex() {
print(_tabController.index);
setState(() {});
}
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.white,
floatingActionButton: _tabController.index == 0
? FloatingActionButton(
backgroundColor: Colors.pink,
child: Icon(Icons.add),
onPressed: () => print(Localizations.localeOf(context)),
)
: Container(),
body: SafeArea(
child: Padding(
padding: const EdgeInsets.only(top: 2.0),
child: Padding(
padding: EdgeInsets.all(1.0),
child: Column(
children: <Widget>[
Container(
padding: EdgeInsets.all(8.0),
decoration: BoxDecoration(
color: Colors.grey,
borderRadius: BorderRadius.all(
Radius.circular(50),
),
),
child: TabBar(
controller: _tabController,
tabs: <Tab>[
Tab(
text: 'messages',
),
Tab(
text: 'notifications',
)
],
unselectedLabelColor: Colors.black54,
labelColor: Colors.black,
//unselectedLabelStyle: kBoldText,
//labelStyle: kBoldText,
indicatorSize: TabBarIndicatorSize.tab,
indicator: BoxDecoration(
shape: BoxShape.rectangle,
borderRadius: BorderRadius.circular(50),
color: Colors.white,
),
),
),
const SizedBox(height: 10),
Expanded(
child: TabBarView(controller: _tabController, children: [
MessagesTab(),
NotificationsTab(),
]),
),
],
),
),
),
),
);
}
}
class MessagesTab extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Text("MessagesTab");
}
}
class NotificationsTab extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Text("NotificationsTab");
}
}
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: Notifications(),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
void _incrementCounter() {
setState(() {
_counter++;
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
'You have pushed the button this many times:',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.headline4,
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: Icon(Icons.add),
),
);
}
}