Flutter/Firebase - Merge 2 streams and utilise result in PageView Builder - firebase

Question

I am trying to take two streams of data from firebase and merge them into one, then use in my PageView builder in my flutter app. I have managed to get my first stream working (default occasions) but I now need to add another. Here are the two streams:
Stream<QuerySnapshot> getDefaultOccasions(BuildContext context) async*{
yield* Firestore.instance.collection('datestoremember').document('default').collection('Dates_to_Remember').snapshots();
}
Stream<QuerySnapshot> getPersonalOccasions(BuildContext context) async*{
final uid = await Provider.of(context).auth.getCurrentUID();
yield* Firestore.instance.collection('datestoremember').document(uid).collection('Dates_to_Remember').snapshots();
}
I'm not sure the best way to merge the two streams together and then use the result in a Page View Builder:
child: StreamBuilder(
stream: getDefaultOccasions(context),
builder: (context, snapshot) {
if(!snapshot.hasData) return const Text("Loading...");
return new PageView.builder(
itemCount: snapshot.data.documents.length,
controller: PageController(viewportFraction: 0.5),
onPageChanged: (int index) => setState(() => _index = index),
itemBuilder: (_, i) {
return Transform.scale(
scale: i == _index ? 1 : 0.5,
child: Card(
elevation: 6,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(10)),
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Text(snapshot.data.documents[i]['Date'].toDate().day.toString()),
Text(DateFormat.MMMM()
.format(
formatter.parse(snapshot.data.documents[i]['Date'].toDate().toString()))
.toString()),
Padding(
padding: const EdgeInsets.only(
left: 8.0, right: 8.0),
child: FittedBox(
fit: BoxFit.contain,
child: Text(
snapshot.data.documents[i]['Title'],
overflow: TextOverflow.ellipsis,
),
),
)
],
),
),
);
},
);},
),
Here is all the code:
class AccountPage extends StatefulWidget {
#override
_AccountPageState createState() => _AccountPageState();
}
class _AccountPageState extends State<AccountPage> {
List<Category> _categories = [
Category('My History', Icons.history, MyHistory()),
Category('Dates to Remember', Icons.event_note, DatesToRemember()),
Category('Terms and Conditions', Icons.assignment, TermsandConditions()),
Category('Privacy Notice', Icons.security, PrivacyNotice()),
Category('Rate us', Icons.stars, RateUs()),
Category('Send us Feedback', Icons.feedback, GiveUsFeedback())
];
DateFormat formatter = DateFormat('dd-MM-yyyy');
int _index = 0;
#override
Widget build(BuildContext context) {
return SingleChildScrollView(
scrollDirection: Axis.vertical,
child: Column(
children: [
Container(
child: SizedBox(
height: 75, // card height
child: StreamBuilder(
stream: getDefaultOccasions(context),
builder: (context, snapshot) {
if(!snapshot.hasData) return const Text("Loading...");
return new PageView.builder(
itemCount: snapshot.data.documents.length,
controller: PageController(viewportFraction: 0.5),
onPageChanged: (int index) => setState(() => _index = index),
itemBuilder: (_, i) {
return Transform.scale(
scale: i == _index ? 1 : 0.5,
child: Card(
elevation: 6,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(10)),
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Text(snapshot.data.documents[i]['Date'].toDate().day.toString()),
Text(DateFormat.MMMM()
.format(
formatter.parse(snapshot.data.documents[i]['Date'].toDate().toString()))
.toString()),
Padding(
padding: const EdgeInsets.only(
left: 8.0, right: 8.0),
child: FittedBox(
fit: BoxFit.contain,
child: Text(
snapshot.data.documents[i]['Title'],
overflow: TextOverflow.ellipsis,
),
),
)
],
),
),
);
},
);},
),
),
),
// SizedBox(height: 100.0,),
Container(
// Page Options
height: MediaQuery
.of(context)
.size
.height * 0.7,
child: ListView.builder(
itemCount: _categories.length,
itemBuilder: (context, index) {
return Column(
children: <Widget>[
ListTile(
leading: Icon(
_categories[index].icon,
color: Colors.black,
),
title: Text(_categories[index].name),
trailing: Icon(Icons.arrow_forward_ios),
onTap: () =>
Navigator.push(
context,
MaterialPageRoute(
builder: (context) =>
_categories[index].route)),
),
Divider(), // <-- Divider
],
);
}),
),
],
),
);
}
}
Stream<QuerySnapshot> getDefaultOccasions(BuildContext context) async*{
yield* Firestore.instance.collection('datestoremember').document('default').collection('Dates_to_Remember').snapshots();
}
Stream<QuerySnapshot> getPersonalOccasions(BuildContext context) async*{
final uid = await Provider.of(context).auth.getCurrentUID();
yield* Firestore.instance.collection('datestoremember').document(uid).collection('Dates_to_Remember').snapshots();
}

Answer 1

You can Merge your two Streams like this:
StreamGroup.merge([getDefaultOccasions(context), getPersonalOccasions(context)]).asBroadcastStream();