How to set state via a method from another class - flutter

Question

Using Flutter and trying to move out a Widget to another class to keep it modular.
Problem is one of the inner Widget has a setState in it. But when I move it out to another class, it is not valid as it is not stateful. Initially thought of passing in a Function and replace that with the setState function itself but that doesn't seem to work. How can I come around this?
Current method that works fine. I plan to move out everything from line 6 (child: Center) to another class as this is going to be repeated via a PageView. Going to be swiping this page to next page, each looking the same, only the text changes.
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.tealAccent,
body: SafeArea(
child: Center(
child: Padding(
padding: const EdgeInsets.all(16.0),
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
Text(
"Did you hear about the claustrophobic astronaut?",
style: TextStyle(
fontSize: 20,
),
),
Text(
"He just needed a little space.",
style: TextStyle(
fontSize: 20,
),
),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
GestureDetector(
child: Icon(heartStatus),
onTap: () {
setState(() {
if (heartStatus == FontAwesomeIcons.heart) {
heartStatus = FontAwesomeIcons.solidHeart;
} else {
heartStatus = FontAwesomeIcons.heart;
}
});
},
),
GestureDetector(
child: Icon(FontAwesomeIcons.shareAlt),
onTap: (){
print('shared');
},
),
],
),
],
),
),
),
),
);
}
This is after moving it to anther class which won't work as set state is not valid here. Passing in function here throws error -> Unnecessary statement
Widget getPageData(Function function){
IconData heartStatus = FontAwesomeIcons.heart;
return Center(
child: Padding(
padding: const EdgeInsets.all(16.0),
child: Column(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
Text(
"Did you hear about the claustrophobic astronaut?",
style: TextStyle(
fontSize: 20,
),
),
Text(
"He just needed a little space.",
style: TextStyle(
fontSize: 20,
),
),
Row(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
GestureDetector(
child: Icon(heartStatus),
onTap: () {
setState(() {
//tried passing in function here
if (heartStatus == FontAwesomeIcons.heart) {
heartStatus = FontAwesomeIcons.solidHeart;
} else {
heartStatus = FontAwesomeIcons.heart;
}
});
},
),
GestureDetector(
child: Icon(FontAwesomeIcons.shareAlt),
onTap: (){
print('shared');
},
),
],
),
],
),
),
);
}

Answer 1

You can turn your function:
Widget getPageData(Function function){...}
To a Customised Widget
class CustomizeWidget extend StatefulWidget{
}
class _CustomizeWidgetState extend State<StatefulWidget>{
/// in the build function, you can call setState
}