main.dart

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_core/firebase_core.dart';
import 'package:flutter/material.dart';
import 'PeopleList.dart';
import 'PeopleUpsert.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  runApp(Main(),);
}

class Main extends StatefulWidget {
  @override
  _MainState createState() => _MainState();
}

class _MainState extends State<Main> {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Chapter 12 Firebase',
      theme: ThemeData(
        primarySwatch: Colors.amber,
      ),
      routes: <String, WidgetBuilder>{
        '/': (BuildContext ctx) => Landing(),
        '/peopleUpsert': (BuildContext ctx) => PeopleUpsert(),
        '/peopleList': (BuildContext ctx) => PeopleList(),
      },
      initialRoute: '/peopleList',
    );
  }
}

class Landing extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Ajax and Firebase'),
      ),
      body: Container(
        color: Colors.amber,
      ),
    );
  }
}

PeopleList.dart

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';
import 'Person.dart';

class PeopleList extends StatefulWidget {
  @override
  _PeopleListState createState() => _PeopleListState();
}

class _PeopleListState extends State<PeopleList> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('People Maintenance'),
      ),
      body: body,
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          Navigator.pushNamed(context, '/peopleUpsert');
        },
        child: Icon(Icons.add),
      ),
    );
  }

  Widget get body {
    return StreamBuilder<QuerySnapshot>(
      stream: fetchPeople(),
      builder: (BuildContext context, AsyncSnapshot<dynamic> snapshot) {
        if (snapshot.hasError) {
          return Text('Oh no! Error! ${snapshot.error}');
        }
        if (!snapshot.hasData) {
          return const Text('No people found');
        }
        final List<Widget> widgets =
        snapshot.data.docs.map<Widget>((DocumentSnapshot p) {
          final Person person = Person.fromDocumentSnapshot(p);
          return InkWell(
            child: GestureDetector(
              onTap: () {
                print('tapped');
                Navigator.pushNamed<dynamic>(context, '/peopleUpsert',
                    arguments: person)
                    .then((dynamic person) {
                  print(
                      'Do something with person returned: ${person
                          .name['first']}');
                });
              },
              child: Container(
                margin: const EdgeInsets.all(5.0),
                child: Stack(
                  children: <Widget>[
                    if (person.imageUrl != null && person.imageUrl.length > 0)

                      Image.network(person.imageUrl,
                          height: 300, width: 300, fit: BoxFit.cover)
                    else
                      Image.asset('assets/images/NoImage.jpg'),
                    Row(
                      mainAxisAlignment: MainAxisAlignment.spaceBetween,
                      children: <Widget>[
                        Flexible(
                          child: Text(
                            '${p['name']['first']} ${p['name']['last']}',
                            style: Theme
                                .of(context)
                                .textTheme
                                .title
                                .copyWith(color: Colors.white),
                          ),
                        ),
                        IconButton(
                          icon: Icon(
                            Icons.delete,
                            color: Colors.white,
                          ),
                          onPressed: () {
                            deletePerson(person);
                          },
                        )
                      ],
                    ),
                    Align(
                      alignment: Alignment.bottomLeft,
                      child: Text(
                        p['email'],
                        style: Theme
                            .of(context)
                            .textTheme
                            .title
                            .copyWith(color: Colors.white),
                      ),
                    ),
                  ],
                ),
              ),
            ),
          );
        }).toList();
        return GridView.extent(
          maxCrossAxisExtent: 300,
          children: widgets,
        );
      },
    );
  }

  Stream<QuerySnapshot> fetchPeople() {
    return FirebaseFirestore.instance
        .collection('people')
        .limit(100)
        .snapshots();
  }

  void deletePerson(Person personToDelete) {
    FirebaseFirestore.instance
        .collection('people')
        .doc(personToDelete.documentID)
        .delete()
        .catchError((dynamic error) {
      print('Error! $error');
    });
  }
}

PeopleUpsert.dart

import 'package:flutter/material.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'Person.dart';

class PeopleUpsert extends StatefulWidget {
  @override
  _PeopleUpsertState createState() => _PeopleUpsertState();
}

class _PeopleUpsertState extends State<PeopleUpsert> {
  final GlobalKey<FormState> _key = GlobalKey<FormState>();
  Person _person;

  @override
  Widget build(BuildContext context) {
    _person = ModalRoute
        .of(context)
        .settings
        .arguments;
    _person = (_person == null) ? Person() : _person;
    return Scaffold(
      appBar: AppBar(
        title: const Text(
          'People Maintenance',
        ),
      ),
      body: _body,
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          _key.currentState.save();
          updatePersonToFirestore(_person);
          Navigator.pop<Person>(context, _person);
        },
        child: Icon(Icons.save),
      ),
    );
  }

  Widget get _body {
    return Form(
      key: _key,
      child: Container(
          padding: const EdgeInsets.all(20),
          child: Column(
            children: <Widget>[
              personFormField(
                  labelText: 'First name', initialValue: _person.name['first']),
              personFormField(
                  labelText: 'Last name', initialValue: _person.name['last']),
              personFormField(labelText: 'Email', initialValue: _person.email),
              personFormField(
                  labelText: 'Image URL', initialValue: _person.imageUrl),
            ],
          )),
    );
  }

  Widget personFormField(
      {String labelText, String fieldName, String initialValue}) {
    return TextFormField(
      initialValue: initialValue,
      decoration: InputDecoration(labelText: labelText),
      onSaved: (String val) {
        switch (labelText) {
          case 'First name':
            _person.name['first'] = val;
            break;
          case 'Last name':
            _person.name['last'] = val;
            break;
          case 'Email':
            _person.email = val;
            break;
          case 'Image URL':
            _person.imageUrl = val;
            break;
          default:
            throw "Bad person field name. I don't know $labelText";
        }
      },
    );
  }

  void updatePersonToFirestore(Person person) {
    FirebaseFirestore.instance
        .collection('people')
        .doc(_person.documentID)
        .set(<String, dynamic>{
      'name': person.name,
      'email': person.email,
      'imageUrl': person.imageUrl,
    }).then<void>((dynamic doc) {
      print('Document successfully written! $doc');
    }).catchError((dynamic error) {
      print('Error! $error');
    });
  }
}

Person.dart

import 'package:cloud_firestore/cloud_firestore.dart';

class Person {
  Person() {
    name = <String, String>{};
  }

  Person.fromJson(Map<String, dynamic> data) {
    name = data['name'];
    email = data['email'];
    imageUrl = data['imageUrl'];
  }

  Person.fromDocumentSnapshot(DocumentSnapshot data) {
    documentID = data.id;
    imageUrl = data['imageUrl'];
    email = data['email'];
    name = <String, String>{
      'first': data['name']['first'],
      'last': data['name']['last']
    };
  }

  String documentID;
  Map<String, String> name;
  String email;
  String imageUrl;
}