Using TextField raises "No Material Widget" error

Question

Using TextField raises "No Material Widget" error

I'm a newbie to thrill and I tried to follow the example here . I just want to use a TextField widget to get user input. The problem is I am getting "Material widget not found". mistake. What am I doing wrong? Thank.

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.

+23

flutter

user8005219 May 12 '17 at 23:03

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3 answers

The error means that you need to wrap the column inside the Material widget, you can put it as a body on the scaffold or as a home for Materialapp. eg:

 'return MaterialApp(
       home:  new Column(
       mainAxisAlignment: MainAxisAlignment.center,
      children: <Widget>[
       new TextField(
      controller: _controller,
      decoration: new InputDecoration(
        hintText: 'Type something',
      ),
    ),
      );'

or

'return Scaffold(
       body:  new Column(
       mainAxisAlignment: MainAxisAlignment.center,
      children: <Widget>[
       new TextField(
      controller: _controller,
      decoration: new InputDecoration(
        hintText: 'Type something',
      ),
    ),
      );''

0

Maureen josephine 06 Sep At 11:10

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A simple solution:

Instead of using:

void main() {
  runApp(new MyApp());
}

You must use:

void main() => runApp(
  MaterialApp(
    home: MyApp()
  )
);

Hope this helps you!

-1

João rodrigues 23 Apr 19 at 19:05

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Collin jackson · Accepted Answer · 2017-05-13T00:56:22+0000

The error message says:

To enter the widget Material

, you can turn it either directly, or use the widget, containing himself Material

, such as Card

, Dialog

, Drawer

or Scaffold

.

In your case, I would probably wrap yours Column

in Scaffold

. This makes it easier to add other content widgets to the application, such as 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'),
        ),
      ],
    ),
  );
}

Using TextField raises "No Material Widget" error

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