Flutter how to send data from second page with Navigator.pop - flutter

Question

I am trying to get data back from the second screen to the first one:
...
onPressed: () {
sendDataBack(context);
},
...
void sendDataBack(BuildContext context) {
int minSendBack = int.parse(minValueController.text);
int maxSendBack = int.parse(maxValueController.text);
Navigator.pop(context,...);
}
When I use Navigator.pop(context, MaterialPageRout(builder: (context) => main(...)))
I get the error the return type 'void' isn't a 'Widget'. How do I pass two variables back?

Answer 1

Take a look at the following example:
import 'package:flutter/material.dart';
void main() {
runApp(MaterialApp(
title: 'Returning Data',
home: HomeScreen(),
));
}
class HomeScreen extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Returning Data Demo'),
),
body: Center(child: SelectionButton()),
);
}
}
class SelectionButton extends StatelessWidget {
#override
Widget build(BuildContext context) {
return RaisedButton(
onPressed: () {
_navigateAndDisplaySelection(context);
},
child: Text('Pick an option, any option!'),
);
}
// A method that launches the SelectionScreen and awaits the result from
// Navigator.pop.
_navigateAndDisplaySelection(BuildContext context) async {
// Navigator.push returns a Future that completes after calling
// Navigator.pop on the Selection Screen.
final result = await Navigator.push(
context,
MaterialPageRoute(builder: (context) => SelectionScreen()),
);
// After the Selection Screen returns a result, hide any previous snackbars
// and show the new result.
Scaffold.of(context)
..removeCurrentSnackBar()
..showSnackBar(SnackBar(content: Text("$result")));
}
}
class SelectionScreen extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Pick an option'),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Padding(
padding: const EdgeInsets.all(8.0),
child: RaisedButton(
onPressed: () {
// Close the screen and return "Yep!" as the result.
Navigator.pop(context, 'Yep!');
},
child: Text('Yep!'),
),
),
Padding(
padding: const EdgeInsets.all(8.0),
child: RaisedButton(
onPressed: () {
// Close the screen and return "Nope!" as the result.
Navigator.pop(context, 'Nope.');
},
child: Text('Nope.'),
),
)
],
),
),
);
}
}
And read flutter docs carefully.
It's taken from Flutter.dev

Answer 2

you can try this:
in secondScreen Class:
...
onPeressed () {
Navigator.pop(context, returnedData);
}
...
in firstScreen Class:
...
onPeressed () {
result = await Navigator.push(
context,
new MaterialPageRoute(
builder: (context) => new secondScreen();
}
...