Child has an error, I tried invcache/restart, cache restart, nothing happens!!
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Try this,let me know it is work for you
Code
import 'package:flutter/cupertino.dart';
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: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
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>[
TextButton(
onPressed: () {
_handleClickMe();
},
child: Text(
"CLICK ME!",
),
)
],
),
),
);
}
Future<void> _handleClickMe() async {
return showDialog<void>(
context: context,
barrierDismissible: false, // user must tap button!
builder: (BuildContext context) {
return CupertinoAlertDialog(
title: Text('Alert'),
content: Text("Are you Sure"),
actions: <Widget>[
CupertinoDialogAction(
child: Text('OK'),
onPressed: () {
Navigator.of(context).pop();
},
),
CupertinoDialogAction(
child: Text('Cancel'),
onPressed: () {
Navigator.of(context).pop();
},
),
],
);
},
);
}
}
This should do the trick for you:
showDialog(
context: context,
builder: (BuildContext context){
return CupertinoAlertDialog(
...
)
}
)
you didn't implement builder: (BuildContext, context){ return Widget}
let me know if this works for you :)
Related
I'm trying to use Markdown (from package flutter_markdown: ^0.6.6) in a dialog box. Following example returns error:
RenderShrinkWrappingViewport does not support returning intrinsic
dimensions.
This is my code:
import 'package:flutter/material.dart';
import 'package:flutter_markdown/flutter_markdown.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Package flutter_markdown'),
),
body: Center(
child: HelpButtonWithDialog(
title: 'markdown test',
content: '# Help Text\n\n* Text line 1\n*Text Line 2',
),
),
);
}
}
class HelpButtonWithDialog extends StatelessWidget {
final String title;
final String content;
HelpButtonWithDialog({
required this.title,
required this.content,
});
#override
Widget build(BuildContext context) {
return IconButton(
icon: Icon(Icons.help_outline),
onPressed: () => showDialog(
barrierDismissible: true,
context: context,
builder: (BuildContext ctx) => AlertDialog(
title: Text(title),
content: Markdown(
data: content,
shrinkWrap: true,
),
actions: [
TextButton(
onPressed: () => Navigator.of(context).pop(),
child: Text('OK'),
)
],
),
),
);
}
}
I found a workaround by using Dialog and copying parts from AlertDialog. I also filed an enhancement request https://github.com/flutter/flutter/issues/89464 to the Flutter team to get this proper.
Here is the workaround code:
import 'package:flutter/material.dart';
import 'package:flutter_markdown/flutter_markdown.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Package flutter_markdown'),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Text(
'flutter_markdown: Please add example how to use in showDialog'),
Text('https://github.com/flutter/flutter/issues/89464'),
HelpButtonWithDialog(
title: 'markdown test',
content: '# Help Text\n\n* Text line 1\n* Text Line 2',
),
],
),
),
);
}
}
class HelpButtonWithDialog extends StatelessWidget {
final String title;
final String content;
HelpButtonWithDialog({
required this.title,
required this.content,
});
#override
Widget build(BuildContext context) {
final ThemeData theme = Theme.of(context);
final DialogTheme dialogTheme = DialogTheme.of(context);
return IconButton(
icon: Icon(Icons.help_outline),
onPressed: () => showDialog(
barrierDismissible: true,
context: context,
builder: (BuildContext ctx) => Dialog(
child: Column(
mainAxisSize: MainAxisSize.min,
children: [
Container(
padding: EdgeInsets.fromLTRB(24.0, 24.0, 24.0, 24.0),
child: DefaultTextStyle(
style:
dialogTheme.titleTextStyle ?? theme.textTheme.headline6!,
child: Text(title),
),
),
MarkdownBody(
data: content,
shrinkWrap: true,
),
TextButton(
onPressed: () => Navigator.of(context).pop(),
child: Text('OK'),
),
],
),
),
),
);
}
}
Having a problem with getting text to display in my home.dart file when it's entered in the FloatingActionButton.
Below is the code sample. Any suggestions where I am getting it wrong. I believe that the 'String value;' line must be within the same MaterialButton function, though not sure how to do it without ruining it further.
}`
I'm using a simple app here to demonstrade the behavior. You can test by copy and running this:
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: SomeScreen(),
);
}
}
class SomeScreen extends StatefulWidget {
#override
_SomeScreenState createState() => _SomeScreenState();
}
class _SomeScreenState extends State<SomeScreen> {
String value = '';
#override
Widget build(BuildContext context) {
return Scaffold(
floatingActionButton: FloatingActionButton(
onPressed: () async {
await _createDialog(context);
setState(() {});
},
child: Icon(Icons.add),
backgroundColor: Colors.red,
),
body: Container(
color: Colors.blue,
child: Center(
child: Text(value),
),
),
);
}
_createDialog(context) async {
await showDialog(
context: context,
builder: (BuildContext dialogContext) {
return AlertDialog(
title: Text('title'),
content: TextField(
onChanged: (text) {
value = text;
},
),
actions: <Widget>[
FlatButton(
child: Text('buttonText'),
onPressed: () {
Navigator.pop(context);
},
),
],
);
},
);
}
}
I did a simple alert function
Github : https://github.com/mohammad092/first
void newAlert(BuildContext context) {
showDialog(
context: context,
builder: (BuildContext context){
return AlertDialog(
title: Text('title text'),
content: Text('content text'),
actions: [
FlatButton(
onPressed: (){
Navigator.of(context).pop();
},
child: Text('dismiss'),
),
],
);
},
);
}
and i import it to my main.dart
also i imported the file which has the alert function
body: RaisedButton(
child: Text('Alert'),
onPressed: () {
newAlert(context);
}),
...
when i press the button on my device its keeps saying:
======== Exception caught by gesture library ================
The following RangeError was thrown while routing a pointer event:
RangeError (index): Invalid value: Only valid value is 0: 1
You are getting the error because your main.dart is not implemented correctly.You're declaring your RaisedButton directly in the MyApp class, instead you should make another Widget and pass that to MyApp, that will give the correct context to show the alert.
Change your main.dart to this :
import 'package:flutter/material.dart';
import 'package:your_project/alert.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
visualDensity: VisualDensity.adaptivePlatformDensity,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
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(
body: Center(
child: RaisedButton(
child: Text('Alert'),
onPressed: () {
newAlert(context);
},
),
),
);
}
}
Use the below code
Future<void> _showMyDialog() async {
return showDialog<void>(
context: context,
barrierDismissible: false, // user must tap button!
builder: (BuildContext context) {
return AlertDialog(
title: Text('AlertDialog Title'),
content: SingleChildScrollView(
child: ListBody(
children: <Widget>[
Text('This is a demo alert dialog.'),
Text('Would you like to approve of this message?'),
],
),
),
actions: <Widget>[
TextButton(
child: Text('Approve'),
onPressed: () {
Navigator.of(context).pop();
},
),
],
);
},
);
}
body: RaisedButton(
child: Text('Alert'),
onPressed: () {
_showMyDialog()
}),
...
I create a new flutter demo and modify it to use the provider package. But it doesn't work. And here is my code.
class MyState {
MyState();
int cnt = 0;
void increase() {
print("increase. $cnt");
cnt++;
}
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
visualDensity: VisualDensity.adaptivePlatformDensity,
),
home: Provider<MyState>(
create: (_) => MyState(),
child: MyHomePage(title: 'Flutter Demo Home Page'),
),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
'You have pushed the button this many times:',
),
Consumer<MyState>(
builder: (context, state, _) {
return Text(
"${state.cnt}",
style: Theme.of(context).textTheme.headline4,
);
},
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: Provider.of<MyState>(context, listen: false).increase,
tooltip: 'Increment',
child: Icon(Icons.add),
),
);
}
}
When press the button, the UI is not rebuilt. And as the printed messages show, the cnt field of Mystate had been changed. Why? May provider can not be used in statefulwidget?
Provider: You can use Provider to provide a value anywhere in the widget tree. It will not rebuild the widget tree whenever the value changes. It simply passes the model to its descendant's widget in the widget tree.
ChangeNotifierProvider: ChangeNotifierProvider listens for changes in the model object. It rebuilds the dependents widgets whenever ChangeNotifier.notifyListeners is called.
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
home: MyHomePage(),
);
}
}
class MyState with ChangeNotifier {
MyState();
int cnt = 0;
void increase() {
print("increase. $cnt");
cnt++;
notifyListeners();
}
}
class MyHomePage extends StatelessWidget {
#override
Widget build(BuildContext context) {
return ChangeNotifierProvider<MyState>(
create: (context) => MyState(),
child: Scaffold(
appBar: AppBar(
title: Text("Page Title"),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Text(
'You have pushed the button this many times:',
),
Consumer<MyState>(
builder: (context, counter, child) => Text(
'${counter.cnt}',
style: Theme.of(context).textTheme.display1,
),
),
],
),
),
floatingActionButton: Builder(builder: (context) {
return FloatingActionButton(
onPressed: Provider.of<MyState>(context, listen: false).increase,
tooltip: 'Increment',
child: Icon(Icons.add),
);
}),
),
);
}
}
You can copy paste run full code below
Step 1: MyState extends ChangeNotifier and use notifyListeners()
Step 2: Use ChangeNotifierProvider
code snippet
class MyState extends ChangeNotifier {
MyState();
int cnt = 0;
void increase() {
print("increase. $cnt");
cnt++;
notifyListeners();
}
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
...
home: ChangeNotifierProvider(
create: (_) => MyState(),
child: MyHomePage(title: 'Flutter Demo Home Page'),
working demo
full code
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
void main() {
runApp(MyApp());
}
class MyState extends ChangeNotifier {
MyState();
int cnt = 0;
void increase() {
print("increase. $cnt");
cnt++;
notifyListeners();
}
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
visualDensity: VisualDensity.adaptivePlatformDensity,
),
home: ChangeNotifierProvider(
create: (_) => MyState(),
child: MyHomePage(title: 'Flutter Demo Home Page'),
),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
'You have pushed the button this many times:',
),
Consumer<MyState>(
builder: (context, state, _) {
return Text(
"${state.cnt}",
style: Theme.of(context).textTheme.headline4,
);
},
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: Provider.of<MyState>(context, listen: false).increase,
tooltip: 'Increment',
child: Icon(Icons.add),
),
);
}
}
I'm trying to show a dialog box that is in another file in a StatefullWidget but when I call its function nothing is happening.
The reason I want to do this is because there is too much nesting of code in my code so I want to keep things simple and clean.
Below is the dialog.dart file.
import 'package:flutter/material.dart';
class PersonDetailsDialog extends StatefulWidget {
PersonDetailsDialog({Key key}) : super(key: key);
#override
_PersonDetailsDialogState createState() {
return _PersonDetailsDialogState();
}
}
class _PersonDetailsDialogState extends State<PersonDetailsDialog> {
#override
Widget build(BuildContext context) {
Future<void> _neverSatisfied() async {
return showDialog<void>(
context: context,
barrierDismissible: false, // user must tap button!
builder: (BuildContext context) {
return AlertDialog(
title: Text('Rewind and remember'),
content: SingleChildScrollView(
child: ListBody(
children: <Widget>[
Text('You will never be satisfied.'),
Text('You\’re like me. I’m never satisfied.'),
],
),
),
actions: <Widget>[
FlatButton(
child: Text('Regret'),
onPressed: () {
Navigator.of(context).pop();
},
),
],
);
},
);
}
}
}
Below is the main.dart file.
mport 'package:flutter/material.dart';
import 'package:practical_0/homepage.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue
),
home: Homepage(),
);
}
}
Below is homepage.dart file where I'm trying to show the dialog when the user clicks RaisedButton but nothing happens.
import 'package:flutter/material.dart';
class Homepage extends StatelessWidget {
final double heightFactor = 600/896;
#override
Widget build(BuildContext context) {
return Scaffold(
body: Container(
child: RaisedButton(
onPressed: PersonDetailsDialog(), // show dialog
),
),
);
}
}
You have to use ShowDialog Where You want to show dialog.
I hope that following example clear your idea.
class Delete extends StatefulWidget {
#override
_DeleteState createState() => _DeleteState();
}
class _DeleteState extends State<Delete> {
BuildContext parent, child;
#override
Widget build(BuildContext context) => Scaffold(
body: Container(
child: Center(
child: RaisedButton(
onPressed: () {
showDialog(
context: context,
barrierDismissible: false,
child: PersonDetailsDialog());
}, // show dialog
),
),
),
);
}
class PersonDetailsDialog extends StatefulWidget {
PersonDetailsDialog({Key key}) : super(key: key);
#override
_PersonDetailsDialogState createState() {
return _PersonDetailsDialogState();
}
}
class _PersonDetailsDialogState extends State<PersonDetailsDialog> {
#override
Widget build(BuildContext context) {
return AlertDialog(
title: Text('Rewind and remember'),
content: SingleChildScrollView(
child: ListBody(
children: <Widget>[
Text('You will never be satisfied.'),
Text('You\’re like me. I’m never satisfied.'),
],
),
),
actions: <Widget>[
FlatButton(
child: Text('Regret'),
onPressed: () {
Navigator.of(context).pop();
},
),
],
);
}
}
Here is an example:
Show dialog is an async function
child: RaisedButton(
onPressed: () async{
final result = await showDialog(
context: context,
builder: (_) => AlertWidget(),
);
return result;
},