This type of dropdown.. I have tried more times in using a ListTile widget.
You have to use a RadioListTile for this purpose. this code is from the flutter documentation, you can try it:
import 'package:flutter/material.dart';
void main() => runApp(const MyApp());
/// This is the main application widget.
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
static const String _title = 'Flutter Code Sample';
#override
Widget build(BuildContext context) {
return MaterialApp(
title: _title,
home: Scaffold(
appBar: AppBar(title: const Text(_title)),
body: const MyStatefulWidget(),
),
);
}
}
enum SingingCharacter { lafayette, jefferson }
/// This is the stateful widget that the main application instantiates.
class MyStatefulWidget extends StatefulWidget {
const MyStatefulWidget({Key? key}) : super(key: key);
#override
State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
}
/// This is the private State class that goes with MyStatefulWidget.
class _MyStatefulWidgetState extends State<MyStatefulWidget> {
SingingCharacter? _character = SingingCharacter.lafayette;
#override
Widget build(BuildContext context) {
return Column(
children: <Widget>[
RadioListTile<SingingCharacter>(
title: const Text('Lafayette'),
value: SingingCharacter.lafayette,
groupValue: _character,
onChanged: (SingingCharacter? value) {
setState(() {
_character = value;
});
},
),
RadioListTile<SingingCharacter>(
title: const Text('Thomas Jefferson'),
value: SingingCharacter.jefferson,
groupValue: _character,
onChanged: (SingingCharacter? value) {
setState(() {
_character = value;
});
},
),
],
);
}
}
Related
Lets say i have a button. So..
String buttonTitle = "Upload";
Above is the button title.
Now i have set this in my text of the button. When i upload something, i want this text to be Uploaded so i use setState method for that and hence the title of the button will be updated. But let's suppose i have 100s of buttons which just says Upload and later have to be changed to just Uploaded if something has been uploaded using that button, am i going to create 100 Strings here? This approach doesn't seem good enough to me. Is there a better approach for this in flutter ?
Check this widget as you expect . click on main button it will update all button state after 3 second like uploading
class MyHomePages2 extends StatefulWidget {
MyHomePages2({Key? key}) : super(key: key);
var Upload = "Upload";
#override
State<MyHomePages2> createState() => _MyHomePages2State();
}
class _MyHomePages2State extends State<MyHomePages2> {
#override
Widget build(BuildContext context) {
return ListView(
children: [
ElevatedButton(
onPressed: () {
setState(() {
widget.Upload = "upload";
});
Future.delayed(Duration(seconds: 3), () {
setState(() {
widget.Upload = "uploaded";
});
});
},
child: Text("MainUpload")),
...List.generate(
100,
(index) => Padding(
padding: const EdgeInsets.all(8.0),
child: ElevatedButton(
onPressed: () {}, child: Text("$index ${widget.Upload}")),
))
],
);
}
}
SampleCode Dartpad live code
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
Future<void> main() async {
WidgetsFlutterBinding.ensureInitialized();
runApp(MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return MaterialApp(
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({Key? key, required this.title}) : super(key: key);
final String title;
#override
State<MyHomePage> createState() => _MyHomePageState();
}
int myvalue = 0;
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
#override
void initState() {
// functions().then((int value) {
// setState(() {
// myvalue = value;
// });
// future is completed you can perform your task
// });
}
Future<int> functions() async {
// do something here
return Future.value();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(),
body: MyHomePages2(),
);
}
}
class MyHomePages2 extends StatefulWidget {
MyHomePages2({Key? key}) : super(key: key);
var Upload = "Upload";
#override
State<MyHomePages2> createState() => _MyHomePages2State();
}
class _MyHomePages2State extends State<MyHomePages2> {
#override
Widget build(BuildContext context) {
return ListView(
children: [
ElevatedButton(
onPressed: () {
setState(() {
widget.Upload = "upload";
});
Future.delayed(Duration(seconds: 3), () {
setState(() {
widget.Upload = "uploaded";
});
});
},
child: Text("MainUpload")),
...List.generate(
100,
(index) => Padding(
padding: const EdgeInsets.all(8.0),
child: ElevatedButton(
onPressed: () {}, child: Text("$index ${widget.Upload}")),
))
],
);
}
}
I've made a custom Splashscreen but when I press back button from statless widget, it will go back to Splashcreen "Stateful widget". I've tried WillPopBack but it not work or at least I was not able to use it. How to prevent statless widget to go back to stateful widget?
Here my code:
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(primarySwatch: Colors.blue, fontFamily: 'Monserrat'),
home: const MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({Key? key, required this.title}) : super(key: key);
final String title;
#override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> with TickerProviderStateMixin {
#override
void initState() {
super.initState();
Future.delayed(Duration(seconds: 4), () {
Navigator.of(context).push(
PageRouteBuilder(
transitionDuration: Duration(milliseconds: 1000),
pageBuilder: (BuildContext context, Animation<double> animation,
Animation<double> secondaryAnimation) {
return MainScreen();
},
transitionsBuilder: (BuildContext context,
Animation<double> animation,
Animation<double> secondaryAnimation,
Widget child) {
return Align(
child: FadeTransition(
opacity: animation,
child: child,
),
);
},
),
);
});
}
#override
Widget build(BuildContext context) {
return [...]
}
}
class MainScreen extends StatelessWidget {
#override
Widget build(BuildContext context) {
return [...]
}
}
Thanks in advance
Use pushReplacement instead of push like
super.initState();
Future.delayed(Duration(seconds: 4), () {
Navigator.of(context).pushReplacement( //< this
PageRouteBuilder(
transitionDuration: Duration(milliseconds: 1000),
pageBuilder: (BuildContext context, Animation<double> animation,
Animation<double> secondaryAnimation) {
return MainScreen();
},
More about push and pushReplacement
Code
import 'package:flutter/foundation.dart';
import 'package:web_socket_channel/io.dart';
import 'package:flutter/material.dart';
import 'package:web_socket_channel/web_socket_channel.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
final title = 'WebSocket Demo';
return MaterialApp(
title: title,
home: MyHomePage(
title: title,
channel: IOWebSocketChannel.connect('ws://192.168.0.164:6001/app/KEY'),
),
);
}
}
class MyHomePage extends StatefulWidget {
final String title;
final WebSocketChannel channel;
MyHomePage({Key key, #required this.title, #required this.channel}) : super(key: key);
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Padding(
padding: const EdgeInsets.all(20.0),
child: StreamBuilder(
stream: widget.channel.stream,
builder: (context, snapshot) {
if(snapshot.hasError)
print(snapshot.error);
else {
widget.channel.sink.add("123");
print("XXX : ${snapshot.data}");
}
return Padding(
padding: const EdgeInsets.symmetric(vertical: 24.0),
child: Text(snapshot.hasData ? '${snapshot.data}' : ''),
);
},
),
),
);
}
#override
void dispose() {
widget.channel.sink.close();
super.dispose();
}
}
The output of the Print Statement is
XXX : {"event":"pusher:connection_established","data":"{"socket_id":"943971557.707744157","activity_timeout":30}"}
It does not fetch refreshed data as the Event and Channel isn't mentioned for my laravel backend. Is there a way that can be mentioned or have i got it wrong somewhere else?
class Astate extends State<A>
{
List b=new List<B>();
#override
Widget build(BuildContext context){
b.add(B());
//how do I access theMethod() for the state object for b[0]?
}
}
class B extends StatefulWidget
{
#override
Bstate createState() => Bstate();
}
class Bstate extends State<B>
{
theMethod()
{
//some content
}
#override
Widget build(BuildContext context) {
}
}
Is there a way to access the theMethod() using b[0] from it's corresponding state object?
If not, is there another way to achieve the same?
You can use a GlobalKey with the Widget's state to access the child Widget's methods:
class Main extends StatefulWidget {
#override
_MainState createState() => _MainState();
}
class _MainState extends State<Main> {
GlobalKey<_HomeState> _key = GlobalKey();
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('StackOverflow'),
),
body: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Home(key: _key),
RaisedButton(
onPressed: () => _key.currentState.changeText('new text'),
child: Text('Change text'),
)
],
)
);
}
}
class Home extends StatefulWidget {
Home({Key key}) : super(key: key);
#override
_HomeState createState() => _HomeState();
}
class _HomeState extends State<Home> {
String text = 'initial text';
#override
Widget build(BuildContext context) {
return Center(
child: Text(text)
);
}
void changeText(String newText){
setState(() {
text = newText;
});
}
}
I want to implement a call back from a Stateful widget to another Stateful Widget. (child to parent). The hierarchy is Task (contains) -> ItemBought -> addImage
How do i implement this? Also will the callback function be defined in the Stateful widget or in its state?
This is my current code:
Task.dart
import 'package:flutter/material.dart';
import 'package:flutter_convertor/ItemBought.dart';
class task extends StatelessWidget{
#override
...
}
class taskScreen extends StatefulWidget{
#override
taskState createState() => new taskState();
}
class taskState extends State<taskScreen> {
bool isButtonEnabled = false;
//Callback function i want to call in order to change the state of my Button
formReady(){
setState(() {
isButtonEnabled = !isButtonEnabled ;
});
}
#override
Widget build(BuildContext context) {
Column taskScreen = Column(
children: <Widget>[...
ItemBought(), //ITEMBOUGHT WIDGET
...
Column(
children: <Widget>[
FlatButton(
onPressed: isButtonEnabled ? _completePage : null,
child: Text(
...
),
),
],
)]);
return Scaffold(
appBar: AppBar(
title: Text('Task Screen')),
body: taskScreen,
);
} }
ItemBought.dart
import 'package:flutter/material.dart';
import 'package:flutter_convertor/addImage.dart';
class ItemBought extends StatefulWidget{
#override
_ItemBoughtState createState() => _ItemBoughtState();
}
class _ItemBoughtState extends State<ItemBought> {
...
#override
Widget build(BuildContext context) {
return Container(
child: Column(
children: <Widget> [
...
addImage(),
...
]
)
);
}
}
addImage.dart
import 'package:flutter/material.dart';
import 'package:flutter_convertor/task.dart';
class addImage extends StatefulWidget{
const addImage({this.formReady});
final VoidCallback formReady;
#override
_addImageState createState() => _addImageState();
}
class _addImageState extends State<addImage> {
// const void({taskState.formReady});
// final VoidCallback formReady;
#override
Widget build(BuildContext context) {
return Container(
child: TextField(
onChanged: (text){
formReady(); //ERROR: The method formReady is not defined for the class _addImageState
},
)
);
}
}
How do i call the function formReady from the widget addImage ?
EDIT:
I tried this code, and removed all compile errors however still not getting the desired result:
in addImage.dart
TextField(
onChanged: (text){
addImage().formReady;
}
)
in Itembought.dart
addImage(formReady: (){
ItemBought().formReady;
}
in task.dart
ItemBought(formReady: (){
this.formReady();
}),
class task extends StatelessWidget {
#override
....
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new ItemBought(callback: (data){
String receivedData = data;
},)
],
),
),
);
}
}
class ItemBought extends StatefulWidget {
final void Function(String data) callback;
const ItemBought({Key key, this.callback}) : super(key: key);
#override
_ItemBoughtState createState() => _ItemBoughtState();
}
class _ItemBoughtState extends State<ItemBought> {
#override
Widget build(BuildContext context) {
return Container(
child: new FlatButton(onPressed: (){
widget.callback("Item Id Or name");
}, child: new Text("Bought Item"),),
);
}
}