Why i can't post data from signUp form to firebase

Question

i am a newbie to Flutter and I am building a Flutter mobile app, i don't why i can't post the data from my Sign Up form to the Authentication in fireBase,

It is my Auth class ----------------------------------------------------------------------------

class Auth with ChangeNotifier {
  late String _token;
  late DateTime _expirytDate;
  late String _userId;
  Future<void> signup(String email, String password) async {
    const url =
        'https://identitytoolkit.googleapis.com/v1/accounts:signInWithCustomToken?key=AIzaSyDL5WN64rhcYbYbiLutVA33Ekjixj0M3BE';
    final response = await http.post(Uri.parse(url),
        body: json.encode({
          'email': email,
          'password': password,
          'returnSecureToken': true,

        }));
  }
}

Here is my AuthCard Class

class AuthCard extends StatefulWidget {
  @override
  _AuthCardState createState() => _AuthCardState();
}

class _AuthCardState extends State<AuthCard> {
  final GlobalKey<FormState> _formKey = GlobalKey();
  AuthMode _authMode = AuthMode.Login;
  Map<String, String> _authData = {
    'email': '',
    'password': '',
  };
  var _isLoading = false;
  final _passwordController = TextEditingController();

  Future<void> _submit() async {
    if (!_formKey.currentState!.validate()) {
      // Invalid!
      return;
    }
     _formKey.currentState!.save();
    setState(() {
      _isLoading = true;
    });
    if (_authMode == AuthMode.Login) {
      // Log user in
    } else {
      // Sign user up
     await  Provider.of<Auth>(context).signup(_authData['email']! ,_authData['password']!   );
    }
    setState(() {
      _isLoading = false;
    });
  }

  void _switchAuthMode() {
    if (_authMode == AuthMode.Login) {
      setState(() {
        _authMode = AuthMode.Signup;
      });
    } else {
      setState(() {
        _authMode = AuthMode.Login;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    final deviceSize = MediaQuery.of(context).size;
    return Card(
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(10.0),
      ),
      elevation: 8.0,
      child: Container(
        height: _authMode == AuthMode.Signup ? 320 : 260,
        constraints:
            BoxConstraints(minHeight: _authMode == AuthMode.Signup ? 320 : 260),
        width: deviceSize.width * 0.75,
        padding: EdgeInsets.all(16.0),
        child: Form(
          key: _formKey,
          child: SingleChildScrollView(
            child: Column(
              children: <Widget>[
                TextFormField(
                  decoration: InputDecoration(labelText: 'E-Mail'),
                  keyboardType: TextInputType.emailAddress,
                  validator: (value) {
                    if (value!.isEmpty || !value.contains('@')) {
                      return 'Invalid email!';
                    }
                    return null;
                  },
                  onSaved: (value) {
                    _authData['email'] = value!;
                  },
                ),
                TextFormField(
                  decoration: InputDecoration(labelText: 'Password'),
                  obscureText: true,
                  controller: _passwordController,
                  validator: (value) {
                    if (value!.isEmpty || value.length < 5) {
                      return 'Password is too short!';
                    }
                  },
                  onSaved: (value) {
                    _authData['password'] = value!;
                  },
                ),
                if (_authMode == AuthMode.Signup)
                  TextFormField(
                    enabled: _authMode == AuthMode.Signup,
                    decoration: InputDecoration(labelText: 'Confirm Password'),
                    obscureText: true,
                    validator: _authMode == AuthMode.Signup
                        ? (value) {
                            if (value != _passwordController.text) {
                              return 'Passwords do not match!';
                            }
                          }
                        : null,
                  ),
                SizedBox(
                  height: 20,
                ),
                if (_isLoading)
                  CircularProgressIndicator()
                else
                  Padding(
                    padding: const EdgeInsets.all(8.0),
                    child: ElevatedButton(
                      child: Text(
                          _authMode == AuthMode.Login ? 'LOGIN' : 'SIGN UP'),
                      onPressed: _submit,
                    ),
                  ),
                TextButton(
                  child: Padding(
                    padding:
                        EdgeInsets.symmetric(horizontal: 30.0, vertical: 4),
                    child: Text(
                        '${_authMode == AuthMode.Login ? 'SIGNUP' : 'LOGIN'} INSTEAD'),
                  ),
                  onPressed: _switchAuthMode,
                  style: TextButton.styleFrom(primary: Colors.amber),
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }
}

Here is my Error and I don't understand the error.

Error: Assertion failed:
file:///C:/Users/DELL/development/SDK/flutter/.pub-cache/hosted/pub.dartlang.org/provider-6.0.3/lib/src/provider.dart:274:7
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart 266:49      throw_
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart 29:3        assertFailed       
packages/provider/src/provider.dart 276:11
of
packages/flutter_application_1/screens/auth_screen.dart 114:40
_submit
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/patch/async_patch.dart 84:54                runBody
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/patch/async_patch.dart 123:5                _async
packages/flutter_application_1/screens/auth_screen.dart 101:23
[_submit]
packages/flutter/src/material/ink_well.dart 1072:21
handleTap
packages/flutter/src/gestures/recognizer.dart 253:24
invokeCallback
packages/flutter/src/gestures/tap.dart 627:11
handleTapUp
packages/flutter/src/gestures/tap.dart 306:5
[_checkUp]
packages/flutter/src/gestures/tap.dart 239:7
handlePrimaryPointer
packages/flutter/src/gestures/recognizer.dart 615:9
handleEvent
packages/flutter/src/gestures/pointer_router.dart 98:12
[_dispatch]
packages/flutter/src/gestures/pointer_router.dart 143:9
<fn>
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/private/linked_hash_map.dart 21:13          forEach
packages/flutter/src/gestures/pointer_router.dart 141:17
[_dispatchEventToRoutes]
packages/flutter/src/gestures/pointer_router.dart 127:7
route
packages/flutter/src/gestures/binding.dart 460:19
handleEvent
packages/flutter/src/gestures/binding.dart 440:14
dispatchEvent
packages/flutter/src/rendering/binding.dart 337:11
dispatchEvent
packages/flutter/src/gestures/binding.dart 395:7
[_handlePointerEventImmediately]
packages/flutter/src/gestures/binding.dart 357:5
handlePointerEvent
packages/flutter/src/gestures/binding.dart 314:7
[_flushPointerEventQueue]
packages/flutter/src/gestures/binding.dart 295:7
[_handlePointerDataPacket]
C:/b/s/w/ir/cache/builder/src/out/host_debug/flutter_web_sdk/lib/_engine/engine/platform_dispatcher.dart 1183:13               invoke1

Answer 1

You must use Try-Catch Block when interacting with Futures and await. 2ndly when you are passing the email and password to the Auth class signup function make it clear with Cast that which value you are passing.

See the snippet below with firebase signup entry

class AuthCard extends StatefulWidget {
  const AuthCard({super.key});

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

class _AuthCardState extends State<AuthCard> {
  final GlobalKey<FormState> _formKey = GlobalKey();
  AuthMode _authMode = AuthMode.Login;
  Map<String, String> _authData = {
    'email': '',
    'password': '',
  };
  var _isLoading = false;
  final _passwordController = TextEditingController();

  Future<void> _submit() async {
    if (!_formKey.currentState!.validate()) {
      // Invalid!
      return;
    }
    _formKey.currentState!.save();
    setState(() {
      _isLoading = true;
    });

    try {
      if (_authMode == AuthMode.Login) {
        // return;
      } else {
        await Provider.of<Auth>(context, listen: false).userSignUp(
          _authData['email'] as String,
          _authData['password'] as String,
        );
      }
    } catch (error) {
      print(error);
    }

    setState(() {
      _isLoading = false;
    });
  }

  void _switchAuthMode() {
    if (_authMode == AuthMode.Login) {
      setState(() {
        _authMode = AuthMode.Signup;
      });
    } else {
      setState(() {
        _authMode = AuthMode.Login;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    final deviceSize = MediaQuery.of(context).size;
    return Card(
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(10.0),
      ),
      elevation: 8.0,
      child: Container(
        height: _authMode == AuthMode.Signup ? 320 : 260,
        constraints:
            BoxConstraints(minHeight: _authMode == AuthMode.Signup ? 320 : 260),
        width: deviceSize.width * 0.75,
        padding: EdgeInsets.all(16.0),
        child: Form(
          key: _formKey,
          child: SingleChildScrollView(
            child: Column(
              children: <Widget>[
                TextFormField(
                  decoration: InputDecoration(labelText: 'E-Mail'),
                  keyboardType: TextInputType.emailAddress,
                  validator: (value) {
                    if (value!.isEmpty || !value.contains('@')) {
                      return 'Invalid email!';
                    }
                    return null;
                  },
                  onSaved: (value) {
                    _authData['email'] = value!;
                  },
                ),
                TextFormField(
                  decoration: InputDecoration(labelText: 'Password'),
                  obscureText: true,
                  controller: _passwordController,
                  validator: (value) {
                    if (value!.isEmpty || value.length < 5) {
                      return 'Password is too short!';
                    }
                  },
                  onSaved: (value) {
                    _authData['password'] = value!;
                  },
                ),
                if (_authMode == AuthMode.Signup)
                  TextFormField(
                    enabled: _authMode == AuthMode.Signup,
                    decoration: InputDecoration(labelText: 'Confirm Password'),
                    obscureText: true,
                    validator: _authMode == AuthMode.Signup
                        ? (value) {
                            if (value != _passwordController.text) {
                              return 'Passwords do not match!';
                            }
                          }
                        : null,
                  ),
                SizedBox(
                  height: 20,
                ),
                if (_isLoading)
                  CircularProgressIndicator()
                else
                  Padding(
                    padding: const EdgeInsets.all(8.0),
                    child: ElevatedButton(
                      child: Text(
                          _authMode == AuthMode.Login ? 'LOGIN' : 'SIGN UP'),
                      onPressed: _submit,
                    ),
                  ),
                TextButton(
                  child: Padding(
                    padding:
                        EdgeInsets.symmetric(horizontal: 30.0, vertical: 4),
                    child: Text(
                        '${_authMode == AuthMode.Login ? 'SIGNUP' : 'LOGIN'} INSTEAD'),
                  ),
                  onPressed: _switchAuthMode,
                  style: TextButton.styleFrom(primary: Colors.amber),
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }
}

Here is the signup data posted to the firebase.