Passing data from one widget to another - flutter

Question

I have a list of choice widget and want to pass the selected choice to another widget.
Here is the list of choice widget
class ChoiceChipWidget extends StatefulWidget {
final List<String> reportList;
final Function(String item) onChoiceSelected;
ChoiceChipWidget(this.reportList, this.onChoiceSelected);
#override
_ChoiceChipWidgetState createState() => new _ChoiceChipWidgetState();
}
class _ChoiceChipWidgetState extends State<ChoiceChipWidget> {
String selectedChoice = "";
_buildChoiceList() {
List<Widget> choices = List();
widget.reportList.forEach((item) {
choices.add(Container(
child: ChoiceChip(
label: Text(item),
selected: selectedChoice == item,
onSelected: (selected) {
setState(() {
selectedChoice = item;
widget.onChoiceSelected(item);
print(selectedChoice); //DATA THAT NEEDS TO BE PASSED
});
},
),
));
});
return choices;
}
#override
Widget build(BuildContext context) {
return Wrap(
children: _buildChoiceList(),
);
}
}
I need to pass it to this widget
class AddCashPage extends StatefulWidget {
#override
_AddCashPageState createState() => _AddCashPageState();
}
class _AddCashPageState extends State<AddCashPage> {
void createTodo() async {
if (_formKey.currentState.validate()) {
_formKey.currentState.save();
String repetition = //DATA NEEDS TO GO HERE;
final addCash = AddCash(repetition);
setState(() {
id = addCash.id;
});
}
}
#override
Widget build(BuildContext context) {
return Container(
child: Form(
key: _formKey,
child: Column(
children: <Widget>[
Row(
children: <Widget>[
ChoiceChipWidget(chipList, (item) {
selectedItem = item;
}),
],
),
RaisedButton(
child: Text("Update Cash Flow"),
onPressed: createTodo,
),
],
),
),
);
}
}
I tried making a constructor inside AddCashPage
like this
class AddCashPage extends StatefulWidget {
final ChoiceChipWidget choiceChipWidget;
AddCashPage({Key key, #required this.choiceChipWidget}) : super(key: key);
#override
_AddCashPageState createState() => _AddCashPageState();
}

Answer 1

I think you just missed to call setState() in here:
ChoiceChipWidget(chipList, (item) {
selectedItem = item;
}),
Like this:
ChoiceChipWidget(chipList, (item) {
setState(() => selectedItem = item);
}),
Then you could do this:
AddCash(selectedItem)
Make sure to declare the selectedItem variable inside _AddCashPageState, I don't see it on your code.

Answer 2

Your choice widget passes the data to the AddCashPage via the constructor you created, but you're missing something. You need to pass the data that AddCashPage has to its state (_AddCashState) so that you can use it there. Basically, you need to create one more constructor.
class AddCashPage extends StatefulWidget {
final ChoiceChipWidget choiceChipWidget;
AddCashPage({Key key, #required this.choiceChipWidget}) : super(key: key);
#override
_AddCashPageState createState() => _AddCashPageState(choiceChipWidget: choiceChipWidget);
}
And in _AddCashPageState:
class _AddCashPageState extends State<AddCashPage> {
final choiceChipWidget;
_AddCashPageState({Key key, #required this.choiceChipWidget});
}

Answer 3

To use your passed data inside _AddCashPageState class you can use widget property of the corresponding state of the related Stateful class.
For Ex : To use choice chip widget in your class you can use it like widget.ChoiceChipWidget
Any properties/methods provided in AddCashPage class can be accessed in its State class _AddCashPageState() using widget.ChoiceChipWidget property;
You can use this widget property inside methods only like, initState(), build(), dispose() etc.