I am building a productivity app using Flutter, Provider, and Firebase. I currently have a number of streams where I take a collection from Firestore and turn them into lists of models. I am running into an issue where when I attempt to create a list of task models, I am returned a null list. Inside Firestore, I have a collection of tasks, statuses, and projects. I would like to set the task.project value equal to the associated Project model from the project collection. main.dart:
void main() {
WidgetsFlutterBinding.ensureInitialized();
runApp(ProductivityApp());
}
class ProductivityApp extends StatefulWidget {
@override
_ProductivityAppState createState() => _ProductivityAppState();
}
class _ProductivityAppState extends State<ProductivityApp> {
bool _initialized = false;
bool _error = false;
void initializeFlutterFire() async {
try {
await Firebase.initializeApp();
setState(() {
_initialized = true;
});
} catch (e) {
_error = true;
}
}
@override
void initState() {
initializeFlutterFire();
super.initState();
}
@override
Widget build(BuildContext context) {
if (_error) {
return Center(child: Text('Something went wrong'));
}
if (!_initialized) {
return Center(child: Text('Loading'));
}
return StreamProvider<User>.value(
value: AuthService().user,
child: MultiProvider( // TODO: fix the issue for user to be logged in for the first time
providers: [
StreamProvider<List<Project>>.value(value: ProjectService().streamProjects()),
StreamProvider<List<Task>>.value(value: TaskService().streamTasks(context)),
StreamProvider<List<Status>>.value(value: StatusService().streamStatuses())
],
child: MaterialApp(
title: 'ProductivityApp',
theme: appTheme(),
// home: Wrapper(),
// routes: routes,
onGenerateRoute: generateRoute,
initialRoute: '/',
),
),
);
}
}
Task Stream:
// Snapshot Conversion to Task Model and Stream
Stream<List<Task>> streamTasks(BuildContext context) {
var ref = _getTaskReference();
return ref.snapshots().map((querySnapshot) => querySnapshot.docs
.map((queryDocument) => Task.fromFirestore(queryDocument, context))
.toList());
}
Task Model:
class Task {
String taskID = '';
String taskName = 'Default Name';
Project project = Project();
Status status = Status();
int taskTime = 0;
DateTime dueDate = DateTime(1);
DateTime createDate = DateTime.now();
// List<String> subtasks = [];
Task(
{this.taskID,
this.taskName,
this.project,
this.status,
this.taskTime,
this.dueDate,
this.createDate});
factory Task.fromFirestore(DocumentSnapshot snapshot, BuildContext context) {
List<Project> projects = Provider.of<List<Project>>(context);
List<Status> statuses = Provider.of<List<Status>>(context);
Map data = snapshot.data();
Project associatedProject = projects
.firstWhere((project) => project.projectName == data['pojectName']);
print(associatedProject);
Status status = statuses
.firstWhere((status) => status.statusName == data['statusName']);
return Task(
taskID: snapshot.id ?? '',
taskName: data['taskName'].toString() ?? '',
project: associatedProject ?? Project(),
status: status ?? Status(),
taskTime: data['taskTime'] ?? 0,
dueDate:
DateTimeFunctions().timeStampToDateTime(date: data['dueDate']) ??
DateTime.now(),
createDate:
DateTimeFunctions().timeStampToDateTime(date: data['createDate']) ??
DateTime.now());
}
}
Thank you for any help!
I have finally figured out a solution to my problem! I used a number of different resources and combined them together to get a working model.
First, I implemented a Auth_widget_builder that is rebuilt based on user info based on this answer. This actually solved a previous issue that was set aside to fix later. By using this approach I am able to rebuild the authentication widget above the material design based on user which I need to access the correct firestore document in my user collection.
main.dart
@override
Widget build(BuildContext context) {
if (_error) {
return Center(child: Text('Something went wrong'));
}
if (!_initialized) {
return Center(child: Text('Loading'));
}
return Provider(
create: (context) => AuthService(),
child: AuthWidgetBuilder(builder: (context, userSnapshot) {
return MaterialApp(
title: 'Productivity App',
theme: appTheme(),
home: AuthWidget(userSnapshot: userSnapshot),
// onGenerateRoute: generateRoute,
// initialRoute: '/',
);
}),
);
}
}
Second, inside the Auth_widget_builder I nested two MultiProviders. The first created Providers that would produce my Service classes. I then added the builder: function based on this answer, which returned the second MultiProvider which held my StreamProviders. This worked because the builder: function rebuilds BuildContext so then I was able to access objects in other Providers to save as a field in another object.
auth_widget_builder.dart
/// Used to create user-dependant objects that need to be accessible by all widgets.
/// This widget should live above the [MaterialApp].
/// See [AuthWidget], a descendant widget that consumes the snapshot generated by this builder.
class AuthWidgetBuilder extends StatelessWidget {
const AuthWidgetBuilder({Key key, @required this.builder}) : super(key: key);
final Widget Function(BuildContext, AsyncSnapshot<UserModel>) builder;
@override
Widget build(BuildContext context) {
print('AuthWidgetBuilder rebuild');
final authService = Provider.of<AuthService>(context, listen: false);
return StreamBuilder<UserModel>(
stream: authService.onAuthStateChanged,
builder: (context, snapshot) {
print('StreamBuilder: ${snapshot.connectionState}');
final UserModel user = snapshot.data;
if (user != null) {
return MultiProvider(
providers: [
Provider<UserModel>.value(value: user),
Provider(create: (context) => ProjectService()),
Provider(create: (context) => StatusService()),
Provider(create: (context) => TaskService()),
Provider(create: (context) => TimeService()),
],
builder: (context, child) {
return MultiProvider(
providers: [
StreamProvider<List<Project>>.value(
value: Provider.of<ProjectService>(context)
.streamProjects()),
StreamProvider<List<Status>>.value(
value: Provider.of<StatusService>(context)
.streamStatuses()),
StreamProvider<List<Task>>.value(
value: Provider.of<TaskService>(context)
.streamTasks(context)),
StreamProvider<List<TimeEntry>>.value(
value: Provider.of<TimeService>(context)
.streamTimeEntries(context))
],
child: builder(context, snapshot),
);
},
child: builder(context, snapshot),
);
}
return builder(context, snapshot);
},
);
}
}
Third, I updated my service classes to find and pass the appropriate objects to the models.
tasks_data.dart
// Snapshot Conversion to Task Model and Stream
Stream<List<Task>> streamTasks(BuildContext context) {
CollectionReference ref = _getTaskReference();
List<Project> projects;
getProjects(context).then((projectList) => projects = projectList);
List<Status> statuses;
getStatuses(context).then((statusList) => statuses = statusList);
return ref.snapshots().map((QuerySnapshot querySnapshot) =>
querySnapshot.docs.map((QueryDocumentSnapshot queryDocument) {
Project project = projects[projects.indexWhere((project) =>
project.projectName ==
queryDocument.data()['projectName'].toString())];
Status status = statuses[statuses.indexWhere((status) =>
status.statusName == queryDocument.data()['status'].toString())];
return Task.fromFirestore(queryDocument, project, status);
}).toList());
}
Future<List<Project>> getProjects(BuildContext context) async {
List<Project> projects =
await Provider.of<ProjectService>(context).streamProjects().first;
return projects;
}
Future<List<Status>> getStatuses(BuildContext context) async {
List<Status> statuses =
await Provider.of<StatusService>(context).streamStatuses().first;
return statuses;
}
The best part about this implementation is that it all happens above the Material Widget which means that I can access it with widgets outside of the normal scope like Navigator.push(). Hopefully this works for anyone needing a similar solution.