Flutter setting variable of CupertinoPicker after showModalBottomSheet - flutter

Question

I'm referencing this answer:https://stackoverflow.com/a/57592970/8616895
Trying to get selectedValue when the bottommodal is closed with WhenComplete.
The function in WhenComplete() is called, but when I print the selectedValue, it only responds as the default, 0. I have checked and SelectedValue does change as I rotate, but the correct value is not retrieved when I close the modal, I assume it has something to do with async or scope. Please share any suggestions.
My class is as follows:
class PopupButton extends StatefulWidget {
final String initialValue;
final List<dynamic> options;
final Function callback;
int initialIndex;
PopupButton(
{#required this.initialValue,
#required this.options,
this.callback,
this.initialIndex = 0});
#override
_PopupButtonState createState() => _PopupButtonState();
}
class _PopupButtonState extends State<PopupButton> {
int selectedValue;
String text = "";
void showPicker(
BuildContext context,
) {
showModalBottomSheet(
context: context,
builder: (BuildContext context) {
return Container(
height: 200,
child: CupertinoPicker(
itemExtent: 32,
onSelectedItemChanged: (value) {
if (mounted) {
setState(() {
selectedValue = value;
});
}
},
children: (widget.options.map((option) => Text(
option,
style: TextStyles.headerLight,
))).toList()),
);
}).whenComplete(() {
// THIS ALWAYS PRINTS 0
print("Selected: $selectedValue");
if (widget.callback != null) {
widget.callback(selectedValue);
}
TextEditingController();
return;
});
}
#override
Widget build(BuildContext context) {
selectedValue = widget.initialIndex;
text = widget.initialValue;
return GestureDetector(
child: Text(text),
onTap: () {
showPicker(context);
},
);
}
}

Answer 1

your mistake is initialization selectedValue in build method.
Every time you call
setState(() {
selectedValue = value;
});
the selectedValue initiated by widget.initialIndex.
Please move selectedValue = widget.initialIndex; to initState method.
#override
void initState() {
super.initState();
selectedValue = widget.initialIndex;
text = widget.initialValue;
}
#override
Widget build(BuildContext context) {
return GestureDetector(
child: Text(text),
onTap: () {
showPicker(context);
},
);
}