The following NoSuchMethodError was thrown building Builder: The getter 'alOne' was called on null. Receiver: null Tried calling: alOne

[Error Place]

anyone knows what has gone wrong here?

i am not getting any warnings in the dart analysis but this error is thrown and the page crashes!

thank you all.

class MondayScreen extends StatefulWidget {
  static final String id = 'monday_screen';
  final User user;

  MondayScreen({this.user});

  @override
  _MondayScreenState createState() => _MondayScreenState();
}

class _MondayScreenState extends State<MondayScreen> {
  final _formKey = GlobalKey<FormState>();

  String _alOne = '';


  @override
  void initState() {
    super.initState();
    _alOne = widget.user.alOne;
  }

  _submit() async {
    if (_formKey.currentState.validate()) {
      _formKey.currentState.save();
      User user = User(
        id: widget.user.id,
        alOne: _alOne,
      );

      DatabaseService.updateUser(user);
      Navigator.pop(context);
    }
  }

//user_models

class User(
final String id;
final String name;

final String profileImageUrl;

final String email;

final String alOne;

)


User({
this.id;
this.name;

this.profileImageUrl;

this.email;

this.bio;

this.alOne;
)}

[Souvik Dutta]

You forgot await inside your async function. That is needed because it takes some time to complete the query. So the initial value is set to null.

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[Error Place]

 TextFormField(
    initialValue: _alOne,
    style: TextStyle(fontSize: 18.0),
    decoration: InputDecoration(
      labelText: 'Alternativ',
    ),
    validator: (input) => input.trim().length > 100
        ? 'Please enter a valid name'
        : null,
    onSaved: (input) => _alOne = input),

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[Suzuki Tomohiro]

Would you share stack trace and your code with line number?

Then I will point out that the variable left to “.alOne” was null.

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[Error Place]

hi suziki.

this is the stack trace

════════ Exception caught by widgets library ═══════════════════════════════════════════════════════

The following NoSuchMethodError was thrown building Builder:

The getter 'alOne' was called on null.

Receiver: null

Tried calling: alOne

The relevant error-causing widget was: 

  MaterialApp file:///Users/alirezamohebbi/AndroidStudioProjects/lunch_nu/lib/main.dart:38:14

When the exception was thrown, this was the stack: 

#0      Object.noSuchMethod (dart:core-patch/object_patch.dart:53:5)

#1      _MondayScreenState.initState (package:lun/screen/monday_screen.dart:28:26)

#2      StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4355:58)

#3      ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)

#4      Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)

...

and this is the line

_alOne = widget.user.alOne;

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[Andy Greenshaw]

So widget.user is null

---

From: flutt...@googlegroups.com <flutt...@googlegroups.com> on behalf of Error Place <reza7....@gmail.com>
Sent: Monday, April 13, 2020 5:02:26 PM
To: Flutter Development (flutter-dev) <flutt...@googlegroups.com>
Subject: Re: The following NoSuchMethodError was thrown building Builder: The getter 'alOne' was called on null. Receiver: null Tried calling: alOne

 

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[Souvik Dutta]

What is the 38th line of your project?

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[Suzuki Tomohiro]

widget.user was null.

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[Suzuki Tomohiro]

Great to heat it’s solved.

On Mon, Apr 13, 2020 at 12:28 PM Error Place <reza7....@gmail.com> wrote:

Thank you guys, Suzuki 🙌🏼 Solved 

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[Souvik Dutta]

Who solved the problem? And how was it solved?

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