Passing down data between widgets - flutter

Question

I have a parent widget _CalendarPageState and two child widgets nameColumnContainer2 and nameColumn2. I have a data under int listLoc = list.indexOf(time); inside nameColumnContainer2 that I want to pass down to nameColumn2
import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import 'update_green_page.dart';
import '../data/repository_service_addcash.dart';
import '../models/addcash.dart';
import 'widget_ui/choice_chip.dart';
class CalendarPage extends StatefulWidget {
#override
_CalendarPageState createState() => _CalendarPageState();
}
class _CalendarPageState extends State<CalendarPage> {
#override
Widget build(BuildContext context) {
return Scaffold(
body: SingleChildScrollView(
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Container(
child: Row(
children: nameColumnContainer2(),
),
),
],
),
),
);
}
List<Widget> nameColumnContainer2() {
var list = <DateTime>[];
DateTime start = DateTime(2019, 12, 01);
final end = DateTime(2021, 12, 31);
while (start.isBefore(end)) {
list.add(start);
start = start.add(const Duration(days: 1));
}
var listDates = list.map((DateTime time) {
return DateFormat("MM-dd-yyyy").format(time);
}).toList();
return list.map((DateTime time) {
int listLoc = list.indexOf(time); //NEED TO PASS THIS DOWN TO nameColumn2
return Container(
decoration: BoxDecoration(border: Border.all(color: Colors.blue)),
width: 120,
child: ListView(
shrinkWrap: true,
children: <Widget>[
FutureBuilder<List<AddCash>>(
future: future,
builder: (context, snapshot) {
if (snapshot.hasData) {
return Column(
children:
snapshot.data.map((todo) => nameColumn2(todo)).toList(),
);
} else {
return SizedBox();
}
},
),
],
),
);
}).toList();
}
Widget nameColumn2(AddCash addCash) {
return Container(
alignment: Alignment.center,
width: 120.0,
height: 60.0,
color: Colors.green,
margin: EdgeInsets.all(4.0),
child: Row(
children: <Widget>[
Text('${addCash.amount}'),
listLoc % 6 == 0
? Text('${addCash.amount}')
: listLoc % 2 == 0 ? Text('no') : Text('d')
],
),
);
}
}
How can I pass the data up to the parent widget so it's available in both widgets?

Answer 1

You should use the BlocProvider widget in your parent widget or directly in your main.dart.
Here is an exemple:
First declare your BlocProvider
final MainBloc mainBloc = MainBloc();
return BlocProvider(
bloc: mainBloc,
child: MaterialApp(
initialRoute: '/CalendarPage',
onGenerateRoute: router.generator,
),
);
BlocProvider content
class BlocProvider extends InheritedWidget {
final MainBloc bloc;
final Widget child;
BlocProvider({Key key, #required this.child, #required this.bloc}) : super(key: key);
static BlocProvider of(BuildContext context) {
return context.inheritFromWidgetOfExactType(BlocProvider);
}
#override
bool updateShouldNotify(InheritedWidget oldWidget) {
return null;
}
}
Create a bloc (so you can separate your logic from your ui) and fill in the data you need
class MainBloc {
//Declare the data you need in your tree
}
And finally to recover your data in your parent/children
your_data = BlocProvider.of(context).bloc.your_data;

Answer 2

I just had to pass listLoc down to nameColumn2