BotZ_app/lib/ui/credentials_form.dart

import 'package:flutter/material.dart';
import 'package:logger/logger.dart';
import 'package:shared_preferences/shared_preferences.dart';

final log = Logger();

class CredentialsForm extends StatefulWidget {
  CredentialsForm({@required this.defaultNextRoute, Key key}) : super(key: key);
  final String defaultNextRoute;

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

class _CredentialsState extends State<CredentialsForm> {
  static String title = "Credentials";
  String username;
  String password;
  bool _hidden = true;
  final _credFormKey = GlobalKey<FormState>();
  final _scaffoldKey = GlobalKey<ScaffoldState>();
  InputDecoration _textFieldDecoration(String label, IconData icon) {
    return InputDecoration(
      labelText: label,
      icon: Icon(icon),
      hintText: 'Please, insert your zucchetti account $label',
    );
  }

  String validateUsername(String username) {
    if (username.isEmpty) {
      return 'Username must not be empty';
    }
    return null;
  }

  String validatePassword(String password) {
    if (password.isEmpty) {
      return 'Password must not be empty';
    }
    return null;
  }

  Future<String> getNextRoute() async {
    var persistence = await SharedPreferences.getInstance();
    String nextRoute = persistence.getString("nextRoute");
    if (nextRoute != null) {
      log.d("nextRoute: $nextRoute");
      return nextRoute;
    }
    log.d("defaultNextRoute: ${widget.defaultNextRoute}");
    return null;
  }

  Future<void> _onPressed() async {
    var persistence = await SharedPreferences.getInstance();
    if (_credFormKey.currentState.validate()) {
      _scaffoldKey.currentState
          .showSnackBar(SnackBar(content: Text('Processing Data')));
    }
    _credFormKey.currentState.save();
    log.d("username: ${this.username}\tpassword: ${this.password}");
    persistence.setString("username", this.username);
    persistence.setString("password", this.password);
    String nextRoute = await getNextRoute();
    if (nextRoute == null) {
      Navigator.pushNamedAndRemoveUntil(
          context, widget.defaultNextRoute, (Route<dynamic> route) => false);
    } else {
      Navigator.pushNamed(context, nextRoute);
    }
  }

  Form theForm() => Form(
      key: _credFormKey,
      child: Column(children: <Widget>[
        TextFormField(
            autofocus: true,
            autocorrect: false,
            decoration:
                this._textFieldDecoration("username", Icons.alternate_email),
            validator: this.validateUsername,
            onSaved: (String user) {
              username = user;
            }),
        TextFormField(
            autocorrect: false,
            decoration: this._textFieldDecoration("password", Icons.lock),
            validator: this.validatePassword,
            obscureText: this._hidden,
            onSaved: (String pass) {
              password = pass;
            }),
        Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: <Widget>[
              RaisedButton(
                onPressed: this._onPressed,
                child: Text('Validate'),
              ),
              Row(children: <Widget>[
                Text('Reveal password'),
                Checkbox(
                    value: !this._hidden,
                    onChanged: (bool value) {
                      setState(() {
                        _hidden = !value;
                      });
                      return;
                    })
              ])
            ]),
      ]));

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        key: _scaffoldKey, appBar: AppBar(title: Text(title)), body: theForm());
  }
}