Flutter Programmatically trigger FutureBuilder - dart

Question

Let's say I have something like this:
return FutureBuilder(
future: _loadingDeals,
builder: (BuildContext context, AsyncSnapshot snapshot) {
return RefreshIndicator(
onRefresh: _handleRefresh,
...
)
}
)
In the _handleRefresh method, I want to programmatically trigger the re-run of the FutureBuilder.
Is there such a thing?
The use case:
When a user pulls down the refreshIndicator, then the _handleRefresh simply makes the FutureBuilder rerun itself.
Edit:
Full code snippet end to end, without the refreshing part. I've switched to using the StreamBuilder, how will the refreshIndicator part fit in all of it?
class DealList extends StatefulWidget {
#override
State<StatefulWidget> createState() => new _DealList();
}
class _DealList extends State<DealList> with AutomaticKeepAliveClientMixin {
// prevents refreshing of tab when switch to
// Why? https://stackoverflow.com/q/51224420/1757321
bool get wantKeepAlive => true;
final RestDatasource api = new RestDatasource();
String token;
StreamController _dealsController;
#override
void initState() {
super.initState();
_dealsController = new StreamController();
_loadingDeals();
}
_loadingDeals() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
this.token = prefs.getString('token');
final res =
this.api.checkInterests(this.token).then((interestResponse) async {
_dealsController.add(interestResponse);
return interestResponse;
});
return res;
}
_handleRefresh(data) async {
SharedPreferences prefs = await SharedPreferences.getInstance();
final token = prefs.getString('token');
await this.api.checkInterests(token).then((interestResponse) {
_dealsController.add(interestResponse);
});
return null;
}
#override
Widget build(BuildContext context) {
super.build(context); // <-- this is with the wantKeepAlive thing
return StreamBuilder(
stream: _dealsController.stream,
builder: (BuildContext context, AsyncSnapshot snapshot) {
if (snapshot.hasError) {
...
}
if (snapshot.connectionState != ConnectionState.done) {
return Center(
child: CircularProgressIndicator(),
);
}
if (!snapshot.hasData &&
snapshot.connectionState == ConnectionState.done) {
return Text('No deals');
}
if (snapshot.hasData) {
return ListView.builder(
physics: const AlwaysScrollableScrollPhysics(),
itemCount: snapshot.data['deals'].length,
itemBuilder: (context, index) {
final Map deal = snapshot.data['deals'][index];
return ListTile(
onTap: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => DealsDetailPage(
dealDetail: deal,
),
),
);
},
title: Text(deal['name']),
subtitle: Text(deal['expires']),
);
},
),
}
},
);
}
}

Answer 1

Why not using a StreamBuilder and a Stream instead of a FutureBuilder?
Something like that...
class _YourWidgetState extends State<YourWidget> {
StreamController<String> _refreshController;
...
initState() {
super...
_refreshController = new StreamController<String>();
_loadingDeals();
}
_loadingDeals() {
_refreshController.add("");
}
_handleRefresh(data) {
if (x) _refreshController.add("");
}
...
build(context) {
...
return StreamBuilder(
stream: _refreshController.stream,
builder: (BuildContext context, AsyncSnapshot snapshot) {
return RefreshIndicator(
onRefresh: _handleRefresh(snapshot.data),
...
)
}
);
}
}
I created a Gist with the Flutter main example using the StreamBuilder, check it out

Answer 2

Using StreamBuilder is a solution, however, to trigger the FutureBuilder programmatically, just call setState, it'll rebuild the Widget.
return RefreshIndicator(
onRefresh: () {
setState(() {});
},
...
)

Answer 3

I prefer FutureBuilder over StreamBuilder since I am using Firestore for my project and you get billed by reads so my solution was this
_future??= getMyFuture();
shouldReload(){
setState(()=>_future = null)
}
FutureBuilder(
future: _future,
builder: (context, snapshot){
return Container();
},
)
and any user activity that needs you to get new data simply call shouldReload()