Pass data from dropdown Button Flutter - firebase

Question

i wanted to get the dropdown widget out of there and put it to another place and pass the data to the another page which firestore use it to Query! ,tried many ways:( help! thanks.
String _currentlySelectedlanguage="USA";
final List<String> _dropdownValueslanguage = ["USA", "India"];
Widget dropdownWidgetlanguage() {
return DropdownButton(
isExpanded: false,
value: _currentlySelectedlanguage,
onChanged: (String newvalue) {
setState(() {
_currentlySelectedlanguage = newvalue;
});
},
items: _dropdownValueslanguage
.map((value) => DropdownMenuItem(
child: Text(value),
value: value,
))
.toList(),
);
}
Future<List<DocumentSnapshot>> getData(String filter) async {
final firestore = FirebaseFirestore.instance;
QuerySnapshot snapshot = await firestore
.collection('slideshow')
.where("lang", isEqualTo: _currentlySelectedlanguage)
.get();
return snapshot.docs;
}
}

Answer 1

Try below code
class Code extends StatefulWidget {
#override
_CodeState createState() => _CodeState();
}
String currentLanguage; //updated
class _CodeState extends State<Code> {
#override
Widget build(BuildContext context) {
return Column(
children: [
dropdownWidgetlanguage(),
FutureBuilder<List<DocumentSnapshot>>(
future: getData(_currentlySelectedlanguage),
builder: (context, snapshot) {
if(snapshot.hasData){
return ListView.builder(
itemCount: snapshot.data.length,
shrinkWrap: true,
itemBuilder: (context, index) => snapshot.data[index].data()['name'],);
}else{
return Container();
}
},)
],
);
}
Widget dropdownWidgetlanguage() {
return DropdownButton(
isExpanded: false,
value: _currentlySelectedlanguage,
onChanged: (String newvalue) {
setState(() {
_currentlySelectedlanguage = newvalue;
currentLanguage = newvalue; //updated
});
},
items: _dropdownValueslanguage
.map((value) => DropdownMenuItem(
child: Text(value),
value: value,
))
.toList(),
);
}
String _currentlySelectedlanguage;
final List<String> _dropdownValueslanguage = ["USA", "India"];
Future<List<DocumentSnapshot>> getData(String filter) async {
final firestore = FirebaseFirestore.instance;
QuerySnapshot snapshot = await firestore
.collection('slideshow')
.where("lang", isEqualTo: filter)
.get();
return snapshot.docs;
}
}
class SecondClass extends StatefulWidget {
#override
_Class2State createState() => _Class2State();
}
class _Class2State extends State<SecondClass> {
#override
Widget build(BuildContext context) {
return Container(
child: Text(currentLanguage),
);
}
}