How to return data from custom function which uses bottom sheet in flutter - flutter

Question

I made a custom function which opens modal bottom sheet in flutter. Now, I want to get some data back from the sheet to my previous page. How should I do it? I tried to make function's return type as Future<FilterDataModel> and Future, but it's not working. I want that whenever the user clicks on cancel, it should return false and when he presses apply, i should get true with the data.
Here is what I tried -
Future<FilterDataModel> showFilterBottomSheet<T>(
{required BuildContext context}) async {
Some code ...........
FilterDataModel filterData = FilterDataModel();
showModalBottomSheet(
context: context,
isScrollControlled: true,
builder: (context) {
String val = "One";
return StatefulBuilder(
builder: (context, StateSetter setState) {
return Wrap(
children: [
Padding(
padding: EdgeInsets.symmetric(
vertical: getProportionateScreenHeight(20),
horizontal: getProportionateScreenWidth(16),
),
child: Column(
..............
Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
Expanded(
child: InkWell(
onTap: () {
Navigator.pop(context, [false, filterData]);
},
child: Container(
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(8),
border: Border.all(color: Colors.white),
),
padding: EdgeInsets.symmetric(
vertical: getProportionateScreenHeight(16),
),
child: Center(
child: Text(
'Cancel',
style: TextStyle(
color: primaryText2,
fontSize: 16,
),
),
),
),
),
),
SizedBox(
width: getProportionateScreenWidth(20),
),
Expanded(
child: InkWell(
onTap: () {
Navigator.pop(context, [true, filterData]);
},
child: Container(
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(8),
border: Border.all(color: Colors.black38),
),
padding: EdgeInsets.symmetric(
vertical: getProportionateScreenHeight(16),
),
child: Center(
child: Text(
'Apply',
style: TextStyle(
color: primaryOrange,
fontSize: 16,
),
),
),
),
),
),
],
),
],
),
),
],
);
},
);
},
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(16.0),
),
).then((value) {
debugPrint("Coming data");
debugPrint(filterData.academicYear.toString());
return filterData;
});
return filterData;
}
And how I am calling it -
onPressed: () async {
FilterDataModel f = await showFilterBottomSheet(
context: context,
);
print("Here - ${f.academicYear}");
},
I also tried to do it like this -
onPressed: () async {
await showFilterBottomSheet(
context: context,
).then((value) {
print("Inside then");
print(value[0]);
print(value[1].toString());
});
print("Here - ${f.academicYear}");
},
But it's not working.

Answer 1

You need to await your bottom sheet, to get the result that was returned from the Navigator.pop(context, value). so it will be like.
final res = await showModalBottomSheet(context, ....);
/// this is to make sure that the Navigator.pop(context) from the bottom sheet did not return a null.
if (res != null) {
FilterDataModel filterData = FilterDataModel();
return filterData;
} else {
return anything;
}

Answer 2

looks like when you pop navigator you return List< dynamic> (boolean + filterDataModel)
so the scheme is:
final result = await showModalBottomSheet<dynamic>(){
...
...
return YourWidget(
...
onTap: ()=> Navigator.of(context).pop([false, filterDataModel])
...
)
}
final boolResult = result[0] as boolean;
final dataResult = result[1] as FilterDataModel;`
take a note that if modal is dismissible then return will be null in case it is dismissed without returned value and you will have to handle this case also