How to catch value when back to previous screen? - dart

Question

this is my second class
class SecondClass extends StatefulWidget {
_SecondClassState createState() => _SecondClassState();
}
class _SecondClassState extends State<SecondClass> {
#override
Widget build(BuildContext context) {
Return Container(
RaisedButton(
onPressed: Navigator.of(context).pop('lorem ipsum),
child: Text('Back and get data')
)
);
}
}
this is my first class
class FirstClass extends StatefulWidget {
_FirstClassState createState() => _FirstClassState();
}
class _FirstClassState extends State<FirstClass> {
#override
Widget build(BuildContext context) {
Return Container(
// show data here
);
}
}
How to get string of lorem ipsum and display it in first class, where I should put the code to get that string?

Answer 1

You can see in the screenshot, whatever item is clicked in 2nd screen, it is sent back to page 1 and Button shows the same item.
Here is the full code for a basic implementation.
void main() {
runApp(MaterialApp(home: Page1()));
}
class Page1 extends StatefulWidget {
#override
_Page1State createState() => _Page1State();
}
class _Page1State extends State<Page1> {
String _response = "";
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text("Page 1")),
body: Center(
child: RaisedButton(
child: Text("Go to Page 2"),
onPressed: () {
Navigator.push(context, MaterialPageRoute(builder: (context) => Page2())).then((value) {
setState(() {
_response = value; // you receive here
});
});
},
),
),
);
}
}
class Page2 extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text("Page 2")),
body: ListView.builder(
itemCount: 20,
itemBuilder: (c, i) {
return ListTile(
title: Text("Item ${i}"),
onTap: () {
Navigator.pop(context, "Item ${i}"); // what you pass here
},
);
},
),
);
}
}

Answer 2

Navigator.of(context).push(MaterialPageRoute(builder: (context) => SecondClass())).then((value) {
// value is lorem ipsum
});
You should use this in your FirstClass when you are navigating to the SecondClass.
Full solution:
class _FirstClassState extends State<FirstClass> {
String _string = "";
#override
Widget build(BuildContext context) {
return RaisedButton(
child: Text("Go"),
onPressed: () {
Navigator.of(context).push(MaterialPageRoute(builder: (context) => SecondClass())).then(
(value) {
setState(() {
_string = value; // lorem ipsum
});
},
);
},
);
}
}