dismiss database data with listview - flutter

Question

now i made the code like this
FutureBuilder(
future: getData2(),
builder: (context, snapshot) {
if (snapshot.hasData) {
List data = snapshot.data;
return ListView.builder(
shrinkWrap: true,
itemCount: data.length,
itemBuilder: (context, index) {
final item = data[index];
return Dismissible(
key: Key(item['loc3']),
onDismissed: (direction) {
setState(() async {
await openData2().then((value) {
value.delete(
'test2',
where: 'loc3 = ?',
whereArgs: ['loc3'],
);
});
});
},
child: ListTile(
title: Text(item['loc3']),
),
);
},
);
but when i dismiss one item
there's some note in console 'Another exception was thrown: setState() callback argument returned a Future.'
in setState i don't return any variable why they say like this?
and when i first delete one item there is more detail error
The following assertion was thrown while notifying listeners for AnimationController:
I/flutter ( 6018): setState() callback argument returned a Future.
I/flutter ( 6018): The setState() method on PositionedTilesState#6d110 was called with a closure or method that
I/flutter ( 6018): returned a Future. Maybe it is marked as "async".
I/flutter ( 6018): Instead of performing asynchronous work inside a call to setState(), first execute the work (without
I/flutter ( 6018): updating the widget state), and then synchronously update the state inside a call to setState().
I/flutter ( 6018): When the exception was thrown, this was the stack:

Answer 1

I think the 1 problem is that you have an async function inside setState. Change it to this:
...
onDismissed: (direction) async {
await openData2().then((value) {
value.delete(
'test2',
where: 'loc3 = ?',
whereArgs: ['loc3'],
);
});
setState(() {});
},
'''
or this (more readable):
...
onDismissed: (direction) {
Future<void> delete() async {
await openData2().then((value) {
value.delete(
'test2',
where: 'loc3 = ?',
whereArgs: ['loc3'],
);
});
}
setState(() {
delete();
});
},
'''
The point is, you can't have async operations performed inside setState.