Flutter how to update ListView in FutureBuilder - firebase

Question

I want to update my listview which is created in futurebuilder, I want to update this on slider change
FlutterSlider(
values: [150],
min: 0,
max: 150,
onDragging: (handlerIndex, lowerValue, upperValue) {
radius = upperValue;
users.clear();
fut = _gdb.getUsersInRadius(radius);
},
),
and code of futurebuilder and list view
Expanded(
child: FutureBuilder(
future: fut,
builder: (BuildContext context, AsyncSnapshot<dynamic> snapshot) {
if(!snapshot.hasData && snapshot.connectionState == ConnectionState.done){
return Center(
child: Text("No users"));
}else if(snapshot.connectionState == ConnectionState.waiting){
return SpinKitWave(color: Theme.of(context).primaryColor);
}
return StreamBuilder(
stream: snapshot.data,
builder: (BuildContext context, AsyncSnapshot<dynamic> snapshot) {
if(!snapshot.hasData){
return Center(
child: SpinKitWave(
color: Theme.of(context).primaryColor,
));
}else{
print(snapshot.data.length);
users.addAll(snapshot.data);
return ListView.builder(
controller: _scrollController ,
itemCount: users.length,
itemBuilder: (BuildContext ctx, int index){
return GestureDetector(
onTap: (){
Navigator.pushNamed(context, '/userWidget', arguments: users[index]);
},
child: Card(
child: Column(
children: [
Text(users[index].data['username']),
FutureBuilder(
future: FirebaseStorage.instance.ref().child('profilepics').child('${users[index].documentID}.jpg').getDownloadURL(),
builder: (BuildContext context, AsyncSnapshot<dynamic> snapshot) {
if(!snapshot.hasData){
return CircleAvatar();
}
return CircleAvatar(backgroundImage: NetworkImage(snapshot.data) ,) ;//.network(snapshot.data)
},
),
Text(users[index].data['city'] == null ? "No city" : users[index].data['city'] )
],
),
),
);
});
}
},
);
},
),
)
When user will change value of slider new users nearby will be loaded to listview and old will be deleted
Users are downloaded from Firestore using Geoflutterfire,

Answer 1

just call setState when doing fut = _gdb.getUsersInRadius(radius);
About the slider part
FlutterSlider(
values: [sliderValue], // initialize it with 150
min: 0,
max: 150,
onDragging: (handlerIndex, lowerValue, upperValue) {
radius = upperValue;
users.clear();
setState(){(){
sliderValue = upperValue; // update it like this.
fut = _gdb.getUsersInRadius(radius);
}}
},
),