No Material widget found
FlutterFlutter Problem Overview
I am new to Flutter and I was trying do execute the example here. I just want to use the TextField widget to get some user input. The issue is that I get a "No Material widget found." error. What am I doing wrong ? Thank you.
Code:
import 'package:flutter/material.dart';
void main() {
runApp(new MyApp());
}
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return new MaterialApp(
title: 'Flutter Demo',
home: new ExampleWidget(),
);
}
}
/// Opens an [AlertDialog] showing what the user typed.
class ExampleWidget extends StatefulWidget {
ExampleWidget({Key key}) : super(key: key);
@override
_ExampleWidgetState createState() => new _ExampleWidgetState();
}
/// State for [ExampleWidget] widgets.
class _ExampleWidgetState extends State<ExampleWidget> {
final TextEditingController _controller = new TextEditingController();
@override
Widget build(BuildContext context) {
return new Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new TextField(
controller: _controller,
decoration: new InputDecoration(
hintText: 'Type something',
),
),
new RaisedButton(
onPressed: () {
showDialog(
context: context,
child: new AlertDialog(
title: new Text('What you typed'),
content: new Text(_controller.text),
),
);
},
child: new Text('DONE'),
),
],
);
}
}
This is the error stack:
Launching lib/main.dart on Android SDK built for x86 in debug mode...
Built build/app/outputs/apk/app-debug.apk (21.5MB).
I/flutter ( 5187): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter ( 5187): The following assertion was thrown building InputDecorator(decoration: InputDecoration(hintText:
I/flutter ( 5187): "Type something"); baseStyle: null; isFocused: false; isEmpty: true; dirty):
I/flutter ( 5187): No Material widget found.
I/flutter ( 5187): InputDecorator widgets require a Material widget ancestor.
I/flutter ( 5187): In material design, most widgets are conceptually "printed" on a sheet of material. In Flutter's
I/flutter ( 5187): material library, that material is represented by the Material widget. It is the Material widget
I/flutter ( 5187): that renders ink splashes, for instance. Because of this, many material library widgets require that
I/flutter ( 5187): there be a Material widget in the tree above them.
I/flutter ( 5187): To introduce a Material widget, you can either directly include one, or use a widget that contains
I/flutter ( 5187): Material itself, such as a Card, Dialog, Drawer, or Scaffold.
I/flutter ( 5187): The specific widget that could not find a Material ancestor was:
I/flutter ( 5187): InputDecorator(decoration: InputDecoration(hintText: "Type something"); baseStyle: null;
I/flutter ( 5187): isFocused: false; isEmpty: true)
I/flutter ( 5187): The ownership chain for the affected widget is:
I/flutter ( 5187): InputDecorator ← AnimatedBuilder ← Listener ← _GestureSemantics ← RawGestureDetector ←
I/flutter ( 5187): GestureDetector ← TextField ← Column ← ExampleWidget ← _ModalScopeStatus ← ⋯
I/flutter ( 5187):
I/flutter ( 5187): When the exception was thrown, this was the stack:
I/flutter ( 5187): #0 debugCheckHasMaterial.<anonymous closure> (package:flutter/src/material/debug.dart:26)
I/flutter ( 5187): #2 debugCheckHasMaterial (package:flutter/src/material/debug.dart:23)
I/flutter ( 5187): #3 InputDecorator.build (package:flutter/src/material/input_decorator.dart:334)
... <output omitted>
I/flutter ( 5187): (elided one frame from class _AssertionError)
I/flutter ( 5187): ════════════════════════════════════════════════════════════════════════════════════════════════════
I/flutter ( 5187): Another exception was thrown: No Material widget found.
Flutter Solutions
Solution 1 - Flutter
The error message says:
> To introduce a Material
widget, you can either directly include one,
> or use a widget that contains Material
itself, such as a Card
,
> Dialog
, Drawer
, or Scaffold
.
In your case, I'd probably wrap your Column
in a Scaffold
. This will make it easy to add other material widgets to your app later, such as an AppBar
, Drawer
, or FloatingActionButton
.
@override
Widget build(BuildContext context) {
return new Scaffold(
body: new Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new TextField(
controller: _controller,
decoration: new InputDecoration(
hintText: 'Type something',
),
),
new RaisedButton(
onPressed: () {
showDialog(
context: context,
child: new AlertDialog(
title: new Text('What you typed'),
content: new Text(_controller.text),
),
);
},
child: new Text('DONE'),
),
],
),
);
}
Solution 2 - Flutter
In my case, I was using a hero widget Inside a scaffold-like this
Scaffold(
body:Hero(
child:ListView(
children:<Widget>[
TextField(),
...
...
]
)
)
);
I simply moved the Hero Widget Outside Scaffold and it solved the problem
Hero(
child:Scaffold(
body:ListView(
children:<Widget>[
TextField(),
...
...
]
)
)
);
Solution 3 - Flutter
Put your widget inside a Scaffold, like this:
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Demo',
//home: MyWidget(), --> do not do this !!!
home: Home() --> this will wrap it in Scaffold
);
}
}
class Home extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Demo'),
),
body: MyWidget()); --> put your widget here
}
}
class MyWidget extends StatefulWidget {
...
Solution 4 - Flutter
Just Wrap your Widegt with Material widget
, it fixes the problem.
Material(
child: InkWell(
onTap: onPressed,));
Solution 5 - Flutter
The error means you have to wrap the column inside a Material widget, you could place it as a body to the scaffold or place it as a home to Materialapp. for instance:
return MaterialApp(
home: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
TextField(
controller: _controller,
decoration: new InputDecoration(hintText: 'Type something'),
),
]
),
);
or
return MaterialApp(
body: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
TextField(
controller: _controller,
decoration: new InputDecoration(hintText: 'Type something'),
),
]
),
);
Solution 6 - Flutter
Solution 7 - Flutter
Instead of InkWell
use GestureDetector
widget, for me fixed issue.
Solution 8 - Flutter
The easy fix is:
Instead of using:void main() {
runApp(new MyApp());
}
You should use:
void main() => runApp(
MaterialApp(
home: MyApp()
)
);
Hope this helps you!