How to send simple data from `secondpage` to `mainpage` (stateful to stateful) - flutter

Question

i found a lot of solution passing data between stateless and stateful widget, but not between two stateful widgets
EDIT: i edited the code to show more details
MainPage
class MainPage extends StatefulWidget {
final String name;
MainPage({Key key, this.name}) : super(key: key);
#override
_MainPageState createState() => _MainPageState();
}
class _MainPageState extends State<MainPage> {
#override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text("Text from 2nd page -> "), //should return "Text from 2nd page -> BATMAN"
FloatingActionButton(
child: Icon(Icons.android),
onPressed: (){
Navigator.push(context, MaterialPageRoute(
builder: (context) => SecondPage()
));
},
),
],
),
),
);
}
}
SecondPage:
class SecondPage extends StatefulWidget {
SecondPage({Key key}) : super(key: key);
#override
_SecondPageState createState() => _SecondPageState();
}
class _SecondPageState extends State<SecondPage> {
#override
Widget build(BuildContext context) {
return Scaffold(
...
Text("I choose ${_selectedMethod.name}"), // this returned "I choose BATMAN"
...
}
So basically i want to pass ${_selectedMethod.name} from 2ndPage to MainPage. sorry im so bad at explaining :(

Answer 1

You can pass variables back to a previous Page in the Navigator stack by sending it through the .pop() method and expecting them in the previous page with the .then() method:
class MainPage60643815 extends StatefulWidget {
#override
_MainPage60643815State createState() => _MainPage60643815State();
}
class _MainPage60643815State extends State<MainPage60643815> {
String displayTextFromSecondPage = '';
#override
Widget build(BuildContext context) {
return Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text('Test from second page: '),
Text(displayTextFromSecondPage),
],
),
RaisedButton(
onPressed: goToSecondPage,
child: Text('Go to 2nd Page'),
),
],
),
);
}
void goToSecondPage(){
Navigator.of(context).push(MaterialPageRoute(
builder: (context) {
return SecondPage60643815(text: displayTextFromSecondPage);
}
)).then((valueFromSecondPage){
setState(() {
displayTextFromSecondPage = valueFromSecondPage;
});
});
}
}
class SecondPage60643815 extends StatefulWidget {
final String text;
SecondPage60643815({this.text});
#override
_SecondPage60643815State createState() => _SecondPage60643815State();
}
class _SecondPage60643815State extends State<SecondPage60643815> {
TextEditingController _textEditingController;
#override
void initState() {
_textEditingController = TextEditingController(
text: widget.text,
);
super.initState();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
leading: IconButton(
icon: Icon(Icons.arrow_back),
onPressed: goToFirstPage,
),
),
body: Center(
child: Padding(
padding: const EdgeInsets.all(8.0),
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
TextFormField(
controller: _textEditingController,
autofocus: true,
),
],
),
),
),
);
}
void goToFirstPage(){
Navigator.of(context).pop(_textEditingController.text);
}
}

Answer 2

I assume that you have a SecondPage-Widget. So you can do something like:
class _MainPageState extends State<MainPage> {
#override
Widget build(BuildContext context) {
return Container(
child: SecondPage('BATMAN'),
);
}
}
This might print the desired "BATMAT" Text.
EDIT
This might be your SecondPage Widget:
class SecondPage extends StatefulWidget {
final String selection;
SecondPage(this.selection);
#override
_SecondPageState createState() => _SecondPageState();
}
class _SecondPageState extends State<SecondPage> {
#override
Widget build(BuildContext context) {
return Container(
child: Text(widget.selection),
);
}
}