No busques más por otros sitios ya que estás al espacio justo, tenemos la solución que necesitas sin complicaciones.
Solución:
Surgen problemas si necesita modificar las matrices. Consisten en que al modificar un array no tiene la oportunidad de utilizar el mismo controlador.
Puede utilizar el siguiente widget personalizado para este caso:
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget
@override
Widget build(BuildContext context)
return MaterialApp(
title: 'Flutter Demo',
home: MyHomePage(),
);
class MyHomePage extends StatefulWidget
@override
_MyHomePageState createState() => _MyHomePageState();
class _MyHomePageState extends State
List data = ['Page 0', 'Page 1', 'Page 2'];
int initPosition = 1;
@override
Widget build(BuildContext context)
return Scaffold(
body: SafeArea(
child: CustomTabView(
initPosition: initPosition,
itemCount: data.length,
tabBuilder: (context, index) => Tab(text: data[index]),
pageBuilder: (context, index) => Center(child: Text(data[index])),
onPositionChange: (index)
print('current position: $index');
initPosition = index;
,
onScroll: (position) => print('$position'),
),
),
floatingActionButton: FloatingActionButton(
onPressed: ()
setState(()
data.add('Page $data.length');
);
,
child: Icon(Icons.add),
),
);
/// Implementation
class CustomTabView extends StatefulWidget
final int itemCount;
final IndexedWidgetBuilder tabBuilder;
final IndexedWidgetBuilder pageBuilder;
final Widget stub;
final ValueChanged onPositionChange;
final ValueChanged onScroll;
final int initPosition;
CustomTabView(
@required this.itemCount,
@required this.tabBuilder,
@required this.pageBuilder,
this.stub,
this.onPositionChange,
this.onScroll,
this.initPosition,
);
@override
_CustomTabsState createState() => _CustomTabsState();
class _CustomTabsState extends State with TickerProviderStateMixin
TabController controller;
int _currentCount;
int _currentPosition;
@override
void initState()
_currentPosition = widget.initPosition ?? 0;
controller = TabController(
length: widget.itemCount,
vsync: this,
initialIndex: _currentPosition,
);
controller.addListener(onPositionChange);
controller.animation.addListener(onScroll);
_currentCount = widget.itemCount;
super.initState();
@override
void didUpdateWidget(CustomTabView oldWidget)
if (_currentCount != widget.itemCount)
controller.animation.removeListener(onScroll);
controller.removeListener(onPositionChange);
controller.dispose();
if (widget.initPosition != null)
_currentPosition = widget.initPosition;
if (_currentPosition > widget.itemCount - 1)
_currentPosition = widget.itemCount - 1;
_currentPosition = _currentPosition < 0 ? 0 :
_currentPosition;
if (widget.onPositionChange is ValueChanged)
WidgetsBinding.instance.addPostFrameCallback((_)
if(mounted)
widget.onPositionChange(_currentPosition);
);
_currentCount = widget.itemCount;
setState(()
controller = TabController(
length: widget.itemCount,
vsync: this,
initialIndex: _currentPosition,
);
controller.addListener(onPositionChange);
controller.animation.addListener(onScroll);
);
else if (widget.initPosition != null)
controller.animateTo(widget.initPosition);
super.didUpdateWidget(oldWidget);
@override
void dispose()
controller.animation.removeListener(onScroll);
controller.removeListener(onPositionChange);
controller.dispose();
super.dispose();
@override
Widget build(BuildContext context)
if (widget.itemCount < 1) return widget.stub ?? Container();
return Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: [
Container(
alignment: Alignment.center,
child: TabBar(
isScrollable: true,
controller: controller,
labelColor: Theme.of(context).primaryColor,
unselectedLabelColor: Theme.of(context).hintColor,
indicator: BoxDecoration(
border: Border(
bottom: BorderSide(
color: Theme.of(context).primaryColor,
width: 2,
),
),
),
tabs: List.generate(
widget.itemCount,
(index) => widget.tabBuilder(context, index),
),
),
),
Expanded(
child: TabBarView(
controller: controller,
children: List.generate(
widget.itemCount,
(index) => widget.pageBuilder(context, index),
),
),
),
],
);
onPositionChange()
if (!controller.indexIsChanging)
_currentPosition = controller.index;
if (widget.onPositionChange is ValueChanged)
widget.onPositionChange(_currentPosition);
onScroll()
if (widget.onScroll is ValueChanged)
widget.onScroll(controller.animation.value);
Prueba esto.
Para hacer una pestaña dinámica, puede usar una Lista y seguir agregando la lista en cada clic de botón.
Truco: borre la lista y vuelva a dibujar un widget vacío y vuelva a dibujar los widgets según su lista.
import 'package:flutter/material.dart';
void main()
runApp(new MaterialApp(
home: new CardStack(),
));
class DynamicTabContent
IconData icon;
String tooTip;
DynamicTabContent.name(this.icon, this.tooTip);
class CardStack extends StatefulWidget
@override
_MainState createState() => new _MainState();
class _MainState extends State with TickerProviderStateMixin
List myList = new List();
TabController _cardController;
TabPageSelector _tabPageSelector;
@override
void initState()
super.initState();
myList.add(new DynamicTabContent.name(Icons.favorite, "Favorited"));
myList.add(new DynamicTabContent.name(Icons.local_pizza, "local pizza"));
_cardController = new TabController(vsync: this, length: myList.length);
_tabPageSelector = new TabPageSelector(controller: _cardController);
@override
void dispose()
_cardController.dispose();
super.dispose();
@override
Widget build(BuildContext context)
return new Scaffold(
backgroundColor: Colors.grey[300],
appBar: new AppBar(
actions: [
new Padding(
padding: const EdgeInsets.all(1.0),
child: new IconButton(
icon: const Icon(
Icons.add,
size: 30.0,
color: Colors.white,
),
tooltip: 'Add Tabs',
onPressed: ()
List tempList = new List();
myList.forEach((dynamicContent)
tempList.add(dynamicContent);
);
setState(()
myList.clear();
);
if (tempList.length % 2 == 0)
myList.add(new DynamicTabContent.name(Icons.shopping_cart, "shopping cart"));
else
myList.add(new DynamicTabContent.name(Icons.camera, "camera"));
tempList.forEach((dynamicContent)
myList.add(dynamicContent);
);
setState(()
_cardController = new TabController(vsync: this, length: myList.length);
_tabPageSelector = new TabPageSelector(controller: _cardController);
);
,
),
),
],
title: new Text("Title Here"),
bottom: new PreferredSize(
preferredSize: const Size.fromHeight(10.0),
child: new Theme(
data: Theme.of(context).copyWith(accentColor: Colors.grey),
child: myList.isEmpty
? new Container(
height: 30.0,
)
: new Container(
height: 30.0,
alignment: Alignment.center,
child: _tabPageSelector,
),
))),
body: new TabBarView(
controller: _cardController,
children: myList.isEmpty
? []
: myList.map((dynamicContent)
return new Card(
child: new Container(
height: 450.0,
width: 300.0,
child: new IconButton(
icon: new Icon(dynamicContent.icon, size: 100.0),
tooltip: dynamicContent.tooTip,
onPressed: null,
)),
);
).toList(),
),
);
Espero que esto ayude 🙂
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