Unable to use currentState Property of GlobalKey in flutter

Question

I m trying to print the current value of my TextField using Globalkey's currentstate as shown:

GlobalkeyName.currentState.value

when i do this inside a Statefull widget am i getting no issue , but when i try to do the same inside a showModalBottomSheet I am getting a error

The getter 'currentState' isn't defined for the class 'Key'.

P.S: I Know how to use TextEditingController Don't Suggest that.

Complete Source code below

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

/// This Widget is the main application widget.
class MyApp extends StatelessWidget {
  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: MyStatelessWidget(),
      ),
    );
  }
}

/// This is the stateless widget that the main application instantiates.
class MyStatelessWidget extends StatelessWidget {
  MyStatelessWidget({Key key}) : super(key: key);
    Key _coffeeformkey=GlobalKey<FormState>();
  Key _nametextfield=GlobalKey<FormFieldState>();
  Key _sugartextfield=GlobalKey<FormFieldState>();

  @override
  Widget build(BuildContext context) {
    return Center(
      child: RaisedButton(
        child: const Text('showModalBottomSheet'),
        onPressed: () {
          showModalBottomSheet<void>(
            context: context,
            builder: (BuildContext context) {
              return Container(
              child: Form(
                key: _coffeeformkey,
                child: Center(
                  heightFactor: 2,
                  child: Column(
                    mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                    // crossAxisAlignment: CrossAxisAlignment.center,
                    mainAxisSize: MainAxisSize.max,

                    children: [
                      //Text("${brews.documents}"),
                      FractionallySizedBox(
                        widthFactor: 0.7,
                        child: TextFormField(
                          key: _nametextfield,
                         // initialValue: usertoselect1.data['name'],
                          //controller: namecontroller,
                          decoration: InputDecoration(hintText: "Enter Email"),
                        ),
                      ),
                      SizedBox(
                        height: 30,
                      ),
                      FractionallySizedBox(
                        widthFactor: .7,
                        child: TextFormField(
                          key: _sugartextfield,
                          //controller: sugarcontroller,
                          //initialValue:await usertoselect1.data['sugar'],
                          decoration: InputDecoration(hintText: "Enter Password"),

                        ),
                      ),
                      SizedBox(
                        height: 30,
                      ),

                      RaisedButton(
                        onPressed:(){
                          //final DatabaseService _database= DatabaseService();
                          print("yyfdyyyyyyyyyyyyyy");
                          print(_sugartextfield.currentState.value);
                          //print(_sugartextfield.r);

                          //print(_sugartextfield.runtimeType);
                           //_database.updateUser(_nametextfield.currentState.value, sugarcontroller.text, 400);
                        },
                        child: Text("Update"),
                        color: Colors.brown,
                      )
                    ],
                  ),
                ),
              ),
            );
            },
          );
        },
      ),
    );
  }
}

Answer 1

Fix the error by changing the declaration of your key to the code below:

// use a global key instead
final GlobalKey<FormState> _formKey = GlobalKey<FormState>();

NOTE: The difference between a Key and GloablKey is explained below:

KEY

A Key is an identifier for Widgets, Elements and SemanticsNodes.

GLOBAL KEY

A key that is unique across the entire app.

To read more about keys, check the link below:

Keys in Flutter

Answer 2

well Apparently declaring the key like this:

final GlobalKey<FormState> _formKey = GlobalKey<FormState>();

instead of like this worked for me:

Key _sugartextfield=GlobalKey<FormFieldState>();