如何在下拉列表中获取所选选项的状态并在Firebase中显示

Question

我有一个用户输入和两个选择选项下拉列表。我从状态中检索了displayName(用户输入值(并将其显示在Firestore数据库中，但是，我无法从状态中获取所选选项(selectedItemA和selectedItemB(并将它们显示在数据库中。

如何获取数据库中显示的这些值(selectedItemA和selectedItemB(？

状态

class UserInfoState with ChangeNotifier {
String _displayName;
dynamic _selectedItemA;
dynamic _selectedItemB;
get displayName => _displayName;
get selectedItemA => _selectedItemA;
get selectedItemB => _selectedItemB;
set displayName(String value) {
_displayName = value;
notifyListeners();
}
set selectedItemA(dynamic value) {
_selectedItemA = value;
notifyListeners();
}
set selectedItemB(dynamic value) {
_selectedItemB = value;
notifyListeners();
}
}
Future<void> updateUserReportWithUserInfo(UserInfoState state) {
return Global.reportRef.upsert(
({
'displayName': state.displayName,
'selectedItemA': state.selectedItemA,
'selectedItemB': state.selectedItemB
}),
);
}

配置文件屏幕

@override
void initState() {
super.initState();
myFocusNode = FocusNode();
_dropdownMenuItemsA = buildDropDownMenuItemsA(_dropdownItemsA);
selectedItemA = _dropdownMenuItemsA[0].value;
_dropdownMenuItemsB = buildDropDownMenuItemsB(_dropdownItemsB);
selectedItemB = _dropdownMenuItemsB[0].value;
}
...
List<DropdownMenuItem<ContinentListItem>> _dropdownMenuItemsA;
ContinentListItem selectedItemA;
List<DropdownMenuItem<ContinentListItem>> buildDropDownMenuItemsA(
List listItems) {
List<DropdownMenuItem<ContinentListItem>> items = List();
for (ContinentListItem listItem in listItems) {
items.add(
DropdownMenuItem(
child: Text(listItem.name),
value: listItem,
),
);
}
return items;
...
floatingActionButton: FloatingActionButton(
backgroundColor: deepOrange,
onPressed: () {
myFocusNode.requestFocus();
updateUserReportWithUserInfo(state);
changeScreen(context, BottomNavBarController());
...

TextField(
focusNode: myFocusNode,
onChanged: (value) => state.displayName = value,
),

DropdownButtonHideUnderline(
child: DropdownButton(
value: selectedItemA,
items: _dropdownMenuItemsA,
onChanged: (value) {
setState(() {
selectedItemA = value;
print(selectedItemA.name);
});
}),
),
...

DropdownButtonHideUnderline(
child: DropdownButton(
value: selectedItemB,
items: _dropdownMenuItemsB,
onChanged: (value) {
setState(() {
selectedItemB = value;
print(selectedItemB.name);
});
class ContinentListItem {
int value;
String name;
ContinentListItem({this.value, this.name});
}

Answer 1

我通过添加state.selectedItemA = selectedItemA.name;解决了这个问题，如下所示：

setState(() {
selectedItemA = value;
});
state.selectedItemA = selectedItemA.name;
}),