flutter sample

register.dart

import 'package:firebase_auth/firebase_auth.dart';
import 'package:flutter/material.dart';

class RegistrationScreen extends StatefulWidget {
  static const routeName = '/register';

  @override
  State<StatefulWidget> createState() {
    return _RegistrationState();
  }
}

class _RegistrationState extends State<RegistrationScreen> {
  final _formKey = GlobalKey<FormState>();

  final _nameController = TextEditingController();
  final _emailController = TextEditingController();
  final _passwordController = TextEditingController();
  final _passwordConfirmController = TextEditingController();

  @override
  void dispose() {
    _nameController.dispose();
    _emailController.dispose();
    _passwordController.dispose();
    _passwordConfirmController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        leading: IconButton(
          icon: Icon(Icons.menu),
          tooltip: 'Navigation menu',
          onPressed: null,
        ),
        title: Text('Registration'),
        actions: [
          IconButton(
            icon: Icon(Icons.search),
            tooltip: 'Search',
            onPressed: null,
          )
        ],
      ),
      body: Padding(
        padding: EdgeInsets.all(16.0),
        child: Form(
          key: _formKey,
          child: Column(
            children: <Widget>[
              TextFormField(
                controller: _nameController,
                decoration: InputDecoration(
                  labelText: 'Enter your name',
                ),
                validator: (value) {
                  if (value.isEmpty) {
                    return 'Please enter your name';
                  }
                  return null;
                },
              ),
              TextFormField(
                controller: _emailController,
                decoration: InputDecoration(
                  labelText: 'Enter your email',
                ),
                validator: (value) {
                  if (value.isEmpty) {
                    return 'Please enter your email';
                  }
                  return null;
                },
              ),
              TextFormField(
                controller: _passwordController,
                decoration: InputDecoration(
                  labelText: 'Enter a valid password',
                ),
                validator: (value) {
                  if (value.isEmpty) {
                    return 'Please enter a valid password';
                  }
                  return null;
                },
              ),
              TextFormField(
                controller: _passwordConfirmController,
                decoration: InputDecoration(
                  labelText: 'Confirm your password',
                ),
                validator: (value) {
                  if (value.isEmpty) {
                    return 'Please confirm your password';
                  }
                  return null;
                },
              ),
              Row(
                children: [
                  RaisedButton(
                    child: Text('Cancel'),
                    onPressed: () {
                      Navigator.pop(context);
                    },
                  ),
                  RaisedButton(
                    onPressed: () async {
                      if (_formKey.currentState.validate()) {
                        String email = _emailController.text;
                        String password = _passwordController.text;
                        await FirebaseAuth.instance
                            .createUserWithEmailAndPassword(
                                email: email, password: password)
                            .then((value) => showDialog(
                                  context: context,
                                  builder: (context) {
                                    return AlertDialog(
                                        content: Text(value.user.uid));
                                  },
                                ))
                            .catchError((error) => print(error));
                      } else {
                        Scaffold.of(context).showSnackBar(
                            SnackBar(content: Text('Error in the form')));
                      }
                    },
                    child: Text('Submit'),
                  )
                ],
              )
            ],
          ),
        ),
      ),
    );
  }
}