TextField keeps old value - flutter

Question

I have an issue with a textfield in flutter.
I need to get a town or postal code to redirect the user to another page. But it seems like I keep old value even if the text inside textfield changes.
I tried to clear it, make conditions but I don't understand why the text does not keep the current value.
Here some code :
Check if it's Paris, for the borough
#override
void initState() {
editingController.addListener((){
setState(() {
if(editingController.text.isEmpty) {
editingController.clear();
isParis = false;
}
});
});
super.initState();
}
Button which redirect, the method getPcFromQuery (it's an async method) retrieve data relatives to a town name.
RaisedButton(
onPressed: (){
print(editingController.text);
getPCFromQuery(editingController.text)
.then((town) {city = town.featureName; postalCode = town.postalCode;});
setState(() {
if(city.toString().toLowerCase() == "paris")
isParis = true;
else
isParis = false;
});
print("postalCode : $postalCode");
postalCode != null && city.toString().toLowerCase() != "paris"?
Navigator.of(context).push(MaterialPageRoute(builder: (context) => PreferencesPage(postalCode: postalCode))) :
Container(child: Text(""));
})
But when I click on the next button (I need to click on it two times to make it work) and when I change the value inside my textfield, it keeps the previously entered value.
Do you know where it can come from?
This is TextField built:
class SearchBar extends StatelessWidget {
const SearchBar({
Key key,
#required this.editingController,
}) : super(key: key) ;
final TextEditingController editingController;
#override
Widget build(BuildContext context) {
return Container(
decoration: BoxDecoration(
color: Colors.grey.withOpacity(0.1),
borderRadius: BorderRadius.circular(10.0)),
child: TextField(
controller: editingController,
decoration: InputDecoration(
hintText: AppStrings.searchTown,
hintStyle: GoogleFonts.notoSans(fontSize: 14.0),
border: InputBorder.none,
fillColor: Colors.grey.withOpacity(0.5),
prefixIcon: Icon(Icons.search, color: Colors.grey)
),
)
);
}
}
And method _getPcFromQuery :
_getPCFromQuery(String city) async {
var addresses = await Geocoder.local.findAddressesFromQuery(city);
var first = addresses.first;
print(first.featureName);
print(first.addressLine);
return first;
}
The weird thing is, when I try the first time, the prints inside _getPcFromQuery method get text, but the print "print("postalCode : $postalCode");" on the onPressed method button is null.

Answer 1

Specify the key parameter for TextField.
class SearchBar extends StatelessWidget {
const SearchBar({
Key key,
#required this.editingController,
}) : super(key: key) ;
final TextEditingController editingController;
final searchKey = GlobalKey(); // <-- create a global key
#override
Widget build(BuildContext context) {
return Container(
decoration: BoxDecoration(
color: Colors.grey.withOpacity(0.1),
borderRadius: BorderRadius.circular(10.0)),
child: TextField(
key: searchKey, // <-- specify the declared key here
controller: editingController,
decoration: InputDecoration(
hintText: AppStrings.searchTown,
hintStyle: GoogleFonts.notoSans(fontSize: 14.0),
border: InputBorder.none,
fillColor: Colors.grey.withOpacity(0.5),
prefixIcon: Icon(Icons.search, color: Colors.grey)
),
)
);
}
}