I am creating an application where I detect a 4-time press power button and perform some action on it I try my self but I unable to perform it please if you have any solution tell me
I am using hardware_buttons: ^1.0.0 packages in my this application.
my code
import 'dart:async';
import 'package:hardware_buttons/hardware_buttons.dart' as HardwareButtons;
void main() {
runApp(MyApp());
}
class MyApp extends StatefulWidget {
#override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
#override
Widget build(BuildContext context) {
return MaterialApp(debugShowCheckedModeBanner: false, home: MyHomeScreen());
}
}
class MyHomeScreen extends StatefulWidget {
MyHomeScreen({Key key, this.title}) : super(key: key);
final String title;
#override
_MyHomeScreenState createState() => _MyHomeScreenState();
}
class _MyHomeScreenState extends State<MyHomeScreen> {
String _latestHardwareButtonEvent;
var counter = 0;
StreamSubscription<HardwareButtons.LockButtonEvent> _lockButtonSubscription;
#override
void initState() {
super.initState();
_lockButtonSubscription =
HardwareButtons.lockButtonEvents.listen((event) {
setState(() {
_latestHardwareButtonEvent = 'LOCK_BUTTON';
});
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
automaticallyImplyLeading: false,
title: Text("Hardware Interaction"),
centerTitle: true,
),
body: Container(
child: Column(
children: [],
),
));
}
}
Related
This question already has answers here:
Flutter calling child class function from parent class
(6 answers)
Closed 7 months ago.
How do I call method of child widget?
class Parent extends StatefulWidget {
const Parent({Key? key}) : super(key: key);
#override
State<Parent> createState() => _ParentState();
}
class _ParentState extends State<Parent> {
#override
Widget build(BuildContext context) {
return Column(
children: [
FloatingActionButton(onPressed: (){
//call child function named funcToCallFromParent
}),
Child(),
],
);
}
}
class Child extends StatefulWidget {
const Child({Key? key}) : super(key: key);
#override
State<Child> createState() => _ChildState();
}
class _ChildState extends State<Child> {
void funcToCallFromParent(){
print('child func called from parent');
}
#override
Widget build(BuildContext context) {
return Container();
}
}
You can use ChangeNotifier to notify the child (or children if you have more than one child that need to be notified) when the parent's button is pressed:
class FloatingActionButtonNotifier extends ChangeNotifier {
void onFloatingActionButtonPressed() => notifyListeners();
}
class Parent extends StatefulWidget {
const Parent({super.key});
#override
State<Parent> createState() => _ParentState();
}
class _ParentState extends State<Parent> {
final FloatingActionButtonNotifier fabNotifier = FloatingActionButtonNotifier();
#override
Widget build(BuildContext context) {
return Column(
children: [
FloatingActionButton(onPressed: fabNotifier.onFloatingActionButtonPressed),
Child(fabNotifier: fabNotifier),
],
);
}
}
class Child extends StatefulWidget {
const Child({
super.key,
required this.fabNotifier,
});
final FloatingActionButtonNotifier fabNotifier;
#override
State<Child> createState() => _ChildState();
}
class _ChildState extends State<Child> {
void funcToCallFromParent() {
print('child func called from parent');
}
#override
void initState() {
super.initState();
widget.fabNotifier.addListener(funcToCallFromParent);
}
#override
void dispose() {
super.dispose();
widget.fabNotifier.removeListener(funcToCallFromParent);
}
#override
Widget build(BuildContext context) {
return Container();
}
}
You can use GlobalKey for Child, and get the state of Child(StatefulWidget). Then call the child's function in the parent widget.
GlobalKey<MyHomePageState> homePageStateKey = GlobalKey<MyHomePageState>();
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
homePageStateKey.currentState?._incrementCounterAfterOneSecond();
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(key: homePageStateKey, title: 'Flutter Demo Home Page'),
);
}
}
You can use a GlobalKey for that.
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
debugShowCheckedModeBanner: false,
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: const MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
final String title;
const MyHomePage({
Key? key,
required this.title,
}) : super(key: key);
#override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
final _key = GlobalKey<_ChildState>();
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(child: Child(key: _key)),
floatingActionButton: FloatingActionButton(
onPressed: () {
// The current state can be null,
// i.e. there is no widget in the tree because it has been unmounted.
_key.currentState?.funcToCallFromParent();
},
tooltip: 'Increment',
child: const Icon(Icons.add),
),
);
}
}
class Child extends StatefulWidget {
const Child({Key? key}) : super(key: key);
#override
State<Child> createState() => _ChildState();
}
class _ChildState extends State<Child> {
void funcToCallFromParent() {
print('child func called from parent');
}
#override
Widget build(BuildContext context) {
return Container();
}
}
See https://api.flutter.dev/flutter/widgets/GlobalKey-class.html
Minimum example:
import 'package:flutter/material.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatefulWidget {
const MyApp({super.key});
#override
State<MyApp> createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
#override
Widget build(BuildContext context) {
return const MaterialApp(
title: 'Welcome to Flutter',
home: Scaffold(
body: CustomScrollView(
slivers: [Example()],
),
));
}
}
class Example extends StatefulWidget {
const Example({Key? key}) : super(key: key);
#override
State<Example> createState() => ExampleState();
}
class ExampleState extends State<Example> with AutomaticKeepAliveClientMixin {
#override
Widget build(BuildContext context) {
super.build(context);
return SliverList(
delegate: SliverChildListDelegate(const <Widget>[
SizedBox(
height: 1400,
),
CheckboxWidget()
], addAutomaticKeepAlives: true));
}
#override
bool get wantKeepAlive => true;
}
class CheckboxWidget extends StatefulWidget {
const CheckboxWidget({Key? key}) : super(key: key);
#override
State<CheckboxWidget> createState() => _CheckboxWidgetState();
}
class _CheckboxWidgetState extends State<CheckboxWidget> {
late bool _personalData = false;
#override
Widget build(BuildContext context) {
return Checkbox(
checkColor: Colors.black,
onChanged: (bool? value) {
setState(() {
_personalData = value!;
});
},
value: _personalData,
);
}
}
If you click the checkbox, then scroll out of view and then back in to view.. The box becomes unchecked. This is because the widget rebuilds...setting the _personalData to false. I would of thought addAutomaticKeepAlives would prevent the widget rebuilding and keep the state of the checkbox. How do I prevent CheckboxWidget from rebuilding?
Firstly, I will choose state management or passing value to the CheckboxWidget. To answer this question, we need to save (keep alive) the state of CheckboxWidget. Therefore, we need to use AutomaticKeepAliveClientMixin on _CheckboxWidgetState instead of parent widget.
class CheckboxWidget extends StatefulWidget {
const CheckboxWidget({Key? key}) : super(key: key);
#override
State<CheckboxWidget> createState() => _CheckboxWidgetState();
}
class _CheckboxWidgetState extends State<CheckboxWidget>
with AutomaticKeepAliveClientMixin {
late bool _personalData = false;
#override
Widget build(BuildContext context) {
super.build(context);
return Checkbox(
checkColor: Colors.black,
onChanged: (bool? value) {
setState(() {
_personalData = value!;
});
},
value: _personalData,
);
}
#override
bool get wantKeepAlive => true;
}
class Example extends StatefulWidget {
const Example({Key? key}) : super(key: key);
#override
State<Example> createState() => ExampleState();
}
class ExampleState extends State<Example> {
#override
Widget build(BuildContext context) {
return SliverList(
delegate: SliverChildListDelegate(
const <Widget>[
SizedBox(
height: 1400,
),
CheckboxWidget()
],
),
);
}
}
please somebody learn me how to do this
the below is very simple version of my code but i want it exactly like this
we have three different files. every one them has one statefull widget
like this
Home.dart
import 'package:flutter/material.dart';
import 'package:gtradar_test_1/GG/appbarz.dart';
import 'package:gtradar_test_1/GG/bodyz.dart';
class Home extends StatefulWidget {
const Home({ Key? key }) : super(key: key);
#override
State<Home> createState() => _HomeState();
}
class _HomeState extends State<Home> {
#override
Widget build(BuildContext context) {
return Scaffold(
body: Bodyz(),
appBar: PreferredSize(preferredSize: Size(20,20),child: AppBarz(),),
);
}
}
Bodyz.dart
import 'package:flutter/material.dart';
class Bodyz extends StatefulWidget {
const Bodyz({ Key? key }) : super(key: key);
#override
State<Bodyz> createState() => _BodyzState();
}
class _BodyzState extends State<Bodyz> {
bool xxx = false;
void xxx_Changer(){
setState(() {
xxx = !xxx;
});
}
#override
Widget build(BuildContext context) {
return Container(
color: Colors.white,
child: xxx? Container(color: Colors.black):SizedBox(),
);
}
}
Appbarz
import 'package:flutter/material.dart';
class AppBarz extends StatefulWidget {
const AppBarz({ Key? key }) : super(key: key);
#override
State<AppBarz> createState() => _AppBarzState();
}
class _AppBarzState extends State<AppBarz> {
#override
Widget build(BuildContext context) {
return AppBar(
leading: IconButton(
icon: Icon(Icons.menu),
onPressed: ?,
),
)
;
}
}
ok,how can i call xxx_Changer() in appbar icon button on pressed or change xxx in appbar?
final ValueChanged onValueChanged;
above Field do the trick... you have to use this and can get the value from appbar class to homeclass then use setState to update your UI
You need to pass xxx_Changer as a function to the AppBarz and get xxx variable as a parameter in Bodyz widget. Like this;
Home.dart
import 'package:flutter/material.dart';
import 'package:gtradar_test_1/GG/appbarz.dart';
import 'package:gtradar_test_1/GG/bodyz.dart';
class Home extends StatefulWidget {
const Home({ Key? key }) : super(key: key);
#override
State<Home> createState() => _HomeState();
}
class _HomeState extends State<Home> {
bool xxx = false;
void xxx_Changer(){
setState(() {
xxx = !xxx;
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
body: Bodyz(xxx: xxx),
appBar: PreferredSize(preferredSize: Size(20,20),child: AppBarz(xxx_Changer: xxx_Changer),),
);
}
}
Bodyz.dart
import 'package:flutter/material.dart';
class Bodyz extends StatefulWidget {
final String xxx;
const Bodyz({ Key? key, this.xxx }) : super(key: key);
#override
State<Bodyz> createState() => _BodyzState();
}
class _BodyzState extends State<Bodyz> {
#override
Widget build(BuildContext context) {
return Container(
color: Colors.white,
child: widget.xxx? Container(color: Colors.black):SizedBox(),
);
}
}
Appbarz
import 'package:flutter/material.dart';
class AppBarz extends StatefulWidget {
final Function xxx_Changer;
const AppBarz({ Key? key, Function xxx_Changer }) : super(key: key);
#override
State<AppBarz> createState() => _AppBarzState();
}
class _AppBarzState extends State<AppBarz> {
#override
Widget build(BuildContext context) {
return AppBar(
leading: IconButton(
icon: Icon(Icons.menu),
onPressed: widget.xxx_Changer(),
),
)
;
}
}
On the example below, since MyStatefulWidget has a state, it doesn't matter if setState is called on _MyAppState, because it will not be redrawn.
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatefulWidget {
#override
State<StatefulWidget> createState() {
return _MyAppState();
}
}
class _MyAppState extends State<MyApp> {
int value = 0;
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(title: Text('App Example')),
body: Row(children:[
MyStatefulWidget(title: value.toString()),
RaisedButton(
textColor: Colors.white,
color: Colors.blue,
onPressed: (){setState(() { value+=1; });},
child: new Text("Add"),
)
]),
),
);
}
}
class MyStatefulWidget extends StatefulWidget {
MyStatefulWidget({Key key, this.title}):super(key: key);
final String title;
#override
State<StatefulWidget> createState() {
return _MyStatefulWidgetState();
}
}
class _MyStatefulWidgetState extends State<MyStatefulWidget> {
String title;
#override
void initState() {
super.initState();
if (widget.title!=null) {
title = widget.title;
} else {
title = "";
}
}
int value = 0;
#override
Widget build(BuildContext context) {
return Text(title);
}
}
If I used a StatelessWidget it'd be redrawn, but this is just an example, there are cases where I need to redraw a StatefulWidget when setState is called.
One option would be to give it a name and build it from the setState, but I need it to be draw in the place where it's draw right now.
Dartpad: https://dartpad.dev/968be8755d5deab1ca5c8c84a993eafc
You could directly use widget.title in the Text widget to update the counter on screen. Please see the code below :
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatefulWidget {
#override
State<StatefulWidget> createState() {
return _MyAppState();
}
}
class _MyAppState extends State<MyApp> {
void changeVal(int val) {
setState(() {
value = val;
});
}
int value = 0;
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(title: const Text('App Example')),
body: Row(children: [
MyStatefulWidget(
title: value.toString(),
groupValue: value % 10,
chnageVal: changeVal),
RaisedButton(
textColor: Colors.white,
color: Colors.blue,
onPressed: () {
setState(() {
value += 1;
});
},
child: const Text("Add"),
)
]),
),
);
}
}
class MyStatefulWidget extends StatefulWidget {
const MyStatefulWidget({Key key, this.title, this.groupValue, this.chnageVal})
: super(key: key);
final String title;
final int groupValue;
final Function(int) chnageVal;
#override
State<StatefulWidget> createState() {
return _MyStatefulWidgetState();
}
}
class _MyStatefulWidgetState extends State<MyStatefulWidget> {
//String title;
// #override
// void initState() {
// super.initState();
// if (widget.title!=null) {
// title = widget.title;
// } else {
// title = "";
// }
// }
//int value = 0;
List<int> numbers = List.generate(10, (index) => index);
#override
Widget build(BuildContext context) {
return Container(
width: 120,
child: Column(children: [
Text(widget.title),
...numbers
.map((number) => RadioListTile<int>(
title: Text('$number'),
value: number,
groupValue: widget.groupValue,
onChanged: (val) {
widget.chnageVal(val);
},
))
.toList()
]),
);
}
}
Just provide a unique key while calling MyStatefulWidget like MyStatefulWidget(key: UniqueKey(), title: value.toString()),.
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatefulWidget {
#override
State<StatefulWidget> createState() {
return _MyAppState();
}
}
class _MyAppState extends State<MyApp> {
int value = 0;
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(title: Text('App Example')),
body: Row(children: [
MyStatefulWidget(key: UniqueKey(), title: value.toString()),
RaisedButton(
textColor: Colors.white,
color: Colors.blue,
onPressed: () {
setState(() {
value += 1;
});
},
child: new Text("Add"),
)
]),
),
);
}
}
class MyStatefulWidget extends StatefulWidget {
MyStatefulWidget({Key key, this.title}) : super(key: key);
final String title;
#override
State<StatefulWidget> createState() {
return _MyStatefulWidgetState();
}
}
class _MyStatefulWidgetState extends State<MyStatefulWidget> {
String title;
#override
void initState() {
super.initState();
if (widget.title != null) {
title = widget.title;
} else {
title = "";
}
}
int value = 0;
#override
Widget build(BuildContext context) {
return Text(title);
}
}
To know more about key please go through this article.
I will recommend using Stream, better performance and not so hard to use for refresh partial UI.
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatefulWidget {
#override
State<StatefulWidget> createState() {
return _MyAppState();
}
}
class _MyAppState extends State<MyApp> {
StreamController<int> _streamController = StreamController();
int value = 0;
#override
void dispose() {
_streamController.close();
super.dispose();
}
#override
Widget build(BuildContext context) {
return MaterialApp(
home:
StreamBuilder<int>(
stream: _streamController.stream,
initialData: value,
builder:
(BuildContext context, AsyncSnapshot<int> snapshot) {
return Scaffold(
appBar: AppBar(title: Text('App Example')),
body: Row(children:[
MyStatefulWidget(title: value.toString()),
RaisedButton(
textColor: Colors.white,
color: Colors.blue,
onPressed: (){_streamController.sink.add(value++);},
child: new Text("Add"),
)
]),
);},),
);
}
}
class MyStatefulWidget extends StatefulWidget {
MyStatefulWidget({Key key, this.title}):super(key: key);
final String title;
#override
State<StatefulWidget> createState() {
return _MyStatefulWidgetState();
}
}
class _MyStatefulWidgetState extends State<MyStatefulWidget> {
String title;
#override
void initState() {
super.initState();
if (widget.title!=null) {
title = widget.title;
} else {
title = "";
}
}
int value = 0;
#override
Widget build(BuildContext context) {
return Text(title);
}
}
I'm trying to store some state during page changes. So old data values are available when a page is reloaded.
I've been looking into PageStorage but haven't figured out how it works yet.
I'm writing into the storage with PageStorage.of(context)?.writeState(context, 'Some text is here', identifier: ValueKey('test')); and then unloading the page with the back button.
When I reload the page (with Navigator.of(context).push()), using PageStorage.of(context)?.readState(context, identifier: ValueKey('test')); just gives me null;
Here's a short sample that I wrote to demonstrate how I'm using it. Does anyone know what I'm doing wrong?
void main() => runApp(new MyApp());
class MyApp extends StatefulWidget {
#override
MyAppState createState() {
return new MyAppState();
}
}
class MyAppState extends State<MyApp> {
final PageStorageBucket _bucket = new PageStorageBucket();
#override
Widget build(BuildContext context) {
return new MaterialApp(
home: PageStorage(
child: new MyHomePage(),
bucket: _bucket,
),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key}) : super(key: key);
#override
_MyHomePageState createState() => new _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
#override
Widget build(BuildContext context) {
return Center(
child: FloatingActionButton(
onPressed: () {
Navigator.of(context).push(new MaterialPageRoute(builder: (context) {
return new NewPage();
}));
},
),
);
}
}
class NewPage extends StatefulWidget {
NewPageState createState() => NewPageState();
}
class NewPageState extends State<NewPage> {
String _text = '';
#override
void initState() {
super.initState();
_text = PageStorage
.of(context)
?.readState(context, identifier: ValueKey('test'));
}
#override
Widget build(BuildContext context) {
return Center(
child: Column(
children: <Widget>[
Text('The text is $_text'),
FloatingActionButton(
onPressed: () {
setState(() {
PageStorage.of(context)?.writeState(
context, 'Some text is here',
identifier: ValueKey('test'));
});
},
)
],
),
);
}
}
There were multiple issues with the code you provided.
The first one being in your MyAppState where you didn't provided a key to your PageStorage. Indeed without the key , the written data cannot be saved and I quote :
writeState(BuildContext context, dynamic data, {Object identifier}) → void
package:flutter
Write the given data into this page storage bucket using the specified identifier or an identifier computed from the given context. The computed identifier is based on the PageStorageKeys found in the path from context to the PageStorage widget that owns this page storage bucket.
If an explicit identifier is not provided and no PageStorageKeys are found, then the data is not saved.
To resolve this just create a global variable PageStorageKey mykey = new PageStorageKey("testkey"); and pass it along the creation of your PageStorage:
class MyAppState extends State<MyApp> {
final PageStorageBucket _bucket = new PageStorageBucket();
#override
Widget build(context) {
return new MaterialApp(
home: PageStorage(
child: new MyHomePage(),
bucket: _bucket,
key: mykey,
),
);
}
}
Then use the same key again to write the data :
onPressed: () {
setState(() {
PageStorage.of(context).writeState(context, 'Data saved',
identifier: ValueKey(mykey));
updateText();
});
Finally the way you update the text is, in my opinion not the best way to do it.
You should create a method (updateText() for example) and call it after you wrote your data.
updateText() {
if (PageStorage.of(context) .readState(context, identifier: ValueKey(mykey)) != null) {
_text = PageStorage .of(context).readState(context, identifier: ValueKey(mykey));
}
else {
_text = 'PageStorageNull';
}
}
As always it's safer to check if the value is non-null to avoid errors.
Here is the full code :
void main() => runApp(new MyApp());
PageStorageKey mykey = new PageStorageKey("testkey");
class MyApp extends StatefulWidget {
#override
MyAppState createState() {
return new MyAppState();
}
}
class MyAppState extends State<MyApp> {
final PageStorageBucket _bucket = new PageStorageBucket();
#override
Widget build(context) {
return new MaterialApp(
home: PageStorage(
child: new MyHomePage(),
bucket: _bucket,
key: mykey,
),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key}) : super(key: key);
#override
_MyHomePageState createState() => new _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
#override
Widget build(context) {
return Center(
child: FloatingActionButton(
onPressed: () {
Navigator.push(context,
new MaterialPageRoute(builder: (context) => new NewPage()));
},
),
);
}
}
class NewPage extends StatefulWidget {
NewPageState createState() => NewPageState();
}
class NewPageState extends State<NewPage> {
String _text;
#override
void initState() {
super.initState();
}
updateText() {
if (PageStorage.of(context) .readState(context, identifier: ValueKey(mykey)) != null) {
_text = PageStorage .of(context).readState(context, identifier: ValueKey(mykey));
}
else {
_text = 'PageStorageNull';
}
}
#override
Widget build(context) {
return Center(
child: Column(
children: <Widget>[
Text('The text is $_text'),
FloatingActionButton(
onPressed: () {
setState(() {
PageStorage.of(context).writeState(context, 'Data saved',
identifier: ValueKey(mykey));
updateText();
});
},
)
],
),
);
}
}
With this code, press the button to go to the second page. On the second page press the button to update the text with the data provided in the writeState() method.
Hoping this can help you,
Regards
EDIT
Fist things first, sorry for misunderstanding the point.
And actually what you want is possible by using Buckets.
Indeed the : PageStorage .of(context).readState(context, identifier: ValueKey(mykey)); can be replace by :
_bucket.readState(context, identifier: ValueKey(mykey));
So what you have to do is make your _bucket variable global, then you need to wrap everything you have in your NewPageState within a PageStorage using the same Key and Bucket as your first PageStorage in the MyAppState
Doing so you will be able to read using the bucket too and keep your data through navigation.
Again he is the full code:
import 'package:flutter/material.dart';
void main() => runApp(new MyApp());
PageStorageKey mykey = new PageStorageKey("testkey");
final PageStorageBucket _bucket = new PageStorageBucket();
class MyApp extends StatefulWidget {
#override
MyAppState createState() {
return new MyAppState();
}
}
class MyAppState extends State<MyApp> {
#override
Widget build(context) {
return new MaterialApp(
home: PageStorage(
child: new MyHomePage(),
bucket: _bucket,
key: mykey,
),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key}) : super(key: key);
#override
_MyHomePageState createState() => new _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
#override
Widget build(context) {
return Center(
child: FloatingActionButton(
onPressed: () {
Navigator.push(context,
new MaterialPageRoute(builder: (context) => new NewPage()));
},
),
);
}
}
class NewPage extends StatefulWidget {
NewPageState createState() => NewPageState();
}
class NewPageState extends State<NewPage> {
String _text;
#override
void initState() {
super.initState();
updateText();
}
updateText() {
if (_bucket.readState(context, identifier: ValueKey(mykey)) != null) {
_text = _bucket.readState(context, identifier: ValueKey(mykey));
}
else {
print(_bucket.toString());
}
}
#override
Widget build(context) {
return PageStorage(
key:mykey,
bucket: _bucket,
child: Column(
children: <Widget>[
Text('The text is $_text'),
FloatingActionButton(
onPressed: () {
setState(() {
_bucket.writeState(context, 'Data saved',
identifier: ValueKey(mykey));
updateText();
});
},
)
],
),
);
}
}