Having a different StreamBuilder for every tab in TabBarView - flutter

Question

I am trying to create a home page that has 3 tabs: Friends, Groups and Events.
After finally managing to load events for the current user only, I realised ill have a hard time loading different data for each tab - as the StreamBuilder stream: will always be the same for all the tabs.
I need help finding a way to have a different StreamBuilder for each of my tabs.
Code below:
StreamBuilder(
stream: _streamer(),//Firestore.instance.collection("Events").snapshots(),
builder: (BuildContext context, AsyncSnapshot<List<dynamic>> snapshot) {
if (!snapshot.hasData) return const Text("Loading...");
return new SizedBox(
height: MediaQuery.of(context).size.height - 42 - MediaQuery.of(context).padding.bottom -AppBar().preferredSize.height - kToolbarHeight,
child: Column(
children: <Widget>[
Expanded(
child: TabBarView(
controller: _tabController,
children: <Widget>[
Container(
child: ListView.separated(
itemCount: snapshot.data.length,
itemBuilder: (context, index) =>
_buildListItem(context,
snapshot.data[index]),
separatorBuilder: (context, index) {
return Divider();
},
shrinkWrap: true,
),
),
Container(
child: ListView.separated(
itemCount: snapshot.data.length,
itemBuilder: (context, index) =>
_buildListItem(context,
snapshot.data[index]),
separatorBuilder: (context, index) {
return Divider();
},
shrinkWrap: true,
),
),
Container(
child: ListView.separated(
itemCount: snapshot.data.length,
itemBuilder: (context, index) =>
_buildListItem(context,
snapshot.data[index]),
separatorBuilder: (context, index) {
return Divider();
},
shrinkWrap: true,
),
),
],
),
)
],
));
},
)
This is how the home page looks

Answer 1

I assume you're loading all data required for all your tabs using that stream. What you could do is have distinct pairs of stream/StreamBuilder for each tab:
... // widgets leading up to the TabBarView
TabBarView(
controller: _controller,
children: <Widget>[
StreamBuilder(
stream: friendsStream,
builder: (BuildContext context, AsyncSnapshot<SomeData> snapshot) {
return FriendsWidget();
}
),
StreamBuilder(
stream: groupsStream,
builder: (BuildContext context, AsyncSnapshot<SomeData> snapshot) {
return GroupsWidget();
}
),
//... etc
]
)
You could also wrap ONLY the widgets that should be rebuilt with a StreamBuilder instead of wrapping the whole parent widget:
... // widgets leading up to the TabBarView
TabBarView(
controller: _controller,
children: <Widget>[
Column(
children: <Widget>[
SomeWidget(),
AnotherWidget(),
StreamBuilder(
stream: friendsStream,
builder: (BuildContext context, AsyncSnapshot<SomeData> snapshot) {
return FriendsWidget();
}
)
]
),
// ... etc
]
)
If you are compelled to load all your data from the database at once, you could use a Repository class to load and store all your data, and then, depending on your architecture, have streams built from that class.
As a side note, I highly recommend using a Bloc with BlocBuilder. Blocs are just far superior to other designs (in most cases). flutter_bloc is my favorite.