Flutter Cloud Firestore issue initializing futures - flutter

Question

I am trying to get my first cloud firestore app working, using the firestore_flutter master example for cloud firestore as a template. In the example app main.dart has all the firestore and other init and access logic, and consequently runs the Futre void() main() method as in the example main.dart section copy below. It does not have the
====================
import...
Future<void> main() async {
WidgetsFlutterBinding.ensureInitialized();
final FirebaseApp app = await FirebaseApp.configure(
name: 'test',
options: const FirebaseOptions(
googleAppID: '1:79601577497:ios:5f2bcc6ba8cecddd',
gcmSenderID: '79601577497',
apiKey: 'AIzaSyArgmRGfB5kiQT6CunAOmKRVKEsxKmy6YI-G72PVU',
projectID: 'flutter-firestore',
),
);
final Firestore firestore = Firestore(app: app);
runApp(MaterialApp(title: 'Firestore Example', home: MyHomePage(firestore: firestore)));
}
class MyHomePage extends StatelessWidget {
MyHomePage({this.firestore});
final Firestore firestore;
CollectionReference get messages => firestore.collection('messages');
====================
But in my app I want to load the data in the 3rd page after authenticating users with firebase_auth, but the main Future function never gets called (only 1 main right?)
Here is my code that does not work because main() never gets called. What do I need to do to make the code below work? PS: I tried making it a called function, moving it, but I am not able to make main run in my page source below.
It doesn't have the next line from teh example in it, because it didn't help either.
runApp(MaterialApp(title: 'Firestore Example', home: TopicList(firestore: firestore)));}
Thanks for any help in advance.
====================
import ...
Future<void> main() async {
WidgetsFlutterBinding.ensureInitialized();
final FirebaseApp app = await FirebaseApp.configure(
name: 'test',
options: const FirebaseOptions(
googleAppID: 'AIzaSyBPq8j3NT5DMmVgXLEN3Z91QJK32ZhrH90',
gcmSenderID: '36424891892',
apiKey: 'AIzaSyArgmRGfB5kiQT6CunAOmKRVKEsxKmy6YI',
projectID: 'usay-94b3a',
),
);
final Firestore firestore = Firestore(app: app);
}
class MessageList extends StatelessWidget {
MessageList({this.firestore});
final Firestore firestore;
#override
Widget build(BuildContext context) {
return StreamBuilder<QuerySnapshot>(
stream: firestore.collection("message").orderBy("timestamp", descending: true).snapshots(),
builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
if (!snapshot.hasData) return const Text('Loading...');
final int messageCount = snapshot.data.documents.length;
return ListView.builder(
itemCount: messageCount,
itemBuilder: (_, int index) {
final DocumentSnapshot document = snapshot.data.documents[index];
final dynamic message = document['message'];
return ListTile(
trailing: IconButton(
onPressed: () => document.reference.delete(),
icon: Icon(Icons.delete),
),
title: Text(
message != null ? message.toString() : '<No message retrieved>',
),
subtitle: Text('Message ${index + 1} of $messageCount'),
);
},
);
},
);
}
}
class TopicList extends StatelessWidget {
TopicList({this.firestore});
final Firestore firestore;
CollectionReference get messages => firestore.collection('message');
Future<void> _addMessage() async {
await messages.add(<String, dynamic>{
'messageTitle': 'Hello world!',
'messageDescription': 'Hello world!',
'timestamp': FieldValue.serverTimestamp(),
});
}
Future<void> _runTransaction() async {
firestore.runTransaction((Transaction transaction) async {
final allDocs = await firestore.collection("message").getDocuments();
final toBeRetrieved = allDocs.documents.sublist(allDocs.documents.length ~/ 2);
final toBeDeleted = allDocs.documents.sublist(0, allDocs.documents.length ~/ 2);
await Future.forEach(toBeDeleted, (DocumentSnapshot snapshot) async {
await transaction.delete(snapshot.reference);
});
await Future.forEach(toBeRetrieved, (DocumentSnapshot snapshot) async {
await transaction.update(snapshot.reference, {
// "messageTitle": FieldValue.messageTitle,
// "messageDescription": FieldValue.messageDescription",
"timestamp": FieldValue.serverTimestamp()
});
});
});
await Future.forEach(List.generate(2, (index) => index), (item) async {
await firestore.runTransaction((Transaction transaction) async {
await Future.forEach(List.generate(10, (index) => index), (item) async {
await transaction.set(firestore.collection("message").document(), {
"messageTitle": "Created from Transaction $item",
"messageDescription": "Created from Transaction $item",
"timestamp": FieldValue.serverTimestamp()
});
});
});
});
}
Future<void> _runBatchWrite() async {
final batchWrite = firestore.batch();
final querySnapshot = await firestore.collection("message").orderBy("timestamp").limit(12).getDocuments();
querySnapshot.documents.sublist(0, querySnapshot.documents.length - 3).forEach((DocumentSnapshot doc) {
batchWrite.updateData(doc.reference, {
"messageTitle": "Batched messageTitle",
"messageDescription": "Batched messageDescription",
"timestamp": FieldValue.serverTimestamp()
});
});
batchWrite.setData(firestore.collection("message").document(), {
"messageTitle": "Batched message created",
"messageDescription": "Batched message created",
"timestamp": FieldValue.serverTimestamp()
});
batchWrite.delete(querySnapshot.documents[querySnapshot.documents.length - 2].reference);
batchWrite.delete(querySnapshot.documents.last.reference);
await batchWrite.commit();
}
#override
Widget build(BuildContext context) {
return FittedBox(
fit: BoxFit.scaleDown,
child: Scaffold(
appBar: AppBar(
title: const Text('Firestore Example'),
actions: <Widget>[
FlatButton(
onPressed: _runTransaction,
child: Text("Run Transaction"),
),
FlatButton(
onPressed: _runBatchWrite,
child: Text("Batch Write"),
)
],
),
body: MessageList(firestore: firestore),
floatingActionButton: FloatingActionButton(
onPressed: _addMessage,
tooltip: 'Increment',
child: const Icon(Icons.add),
),
),
);
}
}
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