Maintain font size during navigation in flutter - flutter

Question

I want the second screen to get only the text size from the first screen and apply it to its text. The font size increases or decreases as a user pinch the screen. So I want to get the desire font size and apply it to the text in the second screen so that the user wouldn't have to pinch the screen anytime he navigate to another screen. How do I do it?
class One extends StatefulWidget {
#override
_OneState createState() => _OneState();
}
class _OneState extends State<One> {
double _prevScale;
double _scale;
#override
void initState() {
super.initState();
_prevScale = _scale = 1.0;
}
#override
Widget build(BuildContext context) {
return GestureDetector(
onScaleUpdate: (ScaleUpdateDetails details) {
setState(() {
_scale = (_prevScale * (details.scale));
});
},
onScaleEnd: (ScaleEndDetails details) {
setState(() {
_prevScale = _scale;
});
},
child: Scaffold(
body: ListView(
children: [
Container(
height: MediaQuery.of(context).size.height/15,
width:MediaQuery.of(context).size.width,
child: Card (
elevation: 0.0,
child: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
IconButton( icon:Icon(Icons.arrow_back), iconSize: 20.0,
padding: EdgeInsets.only(left: 15.0), onPressed: (){
Navigator.of(context).pop();
},
),
IconButton( icon:Icon(Icons.share), iconSize: 20.0,
padding: EdgeInsets.only(right: 10.0), onPressed: (){
},
),
],
),
),
),
Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
IconButton( icon:Icon(Icons.arrow_back_ios), iconSize: 20.0,
padding: EdgeInsets.only(left: 10.0),
),
Text("Selfless", style: TextStyle(fontSize: 20.0, fontFamily:"CrimsonText" ), ),
IconButton( icon:Icon(Icons.arrow_forward_ios), iconSize: 20.0,
padding: EdgeInsets.only(right: 10.0), onPressed: (){
Navigator.of(context).push(MaterialPageRoute(builder: (_)=>Two()));
},
),
],
),
Card(
// shadowColor: Colors.transparent,
shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(20.0)),
elevation: 5.0,
margin: EdgeInsets.all(10.0),
child: Padding(
padding: const EdgeInsets.all(15.0),
child: Column(
children: [
Text("-1-", style: TextStyle(fontSize: (25.0*_scale).clamp(20.0, 70.0), fontFamily:"CrimsonText" )),
Row(
children: [
Expanded(
child: Text("At Wandsworth Prison the Master, ‘Abdu’l-Baha, wrote in the visitors’ book: "
"‘The greatest prison is the prison of self.’",
style: TextStyle(fontSize: (25.0*_scale).clamp(20.0, 70.0), fontFamily:"CrimsonText", height: 1.4 ), ),
),
],
)
],
),
)
)
],
),
),
);
}
}

Answer 1

You can pass the font size (or the scale) from the first page to the second like this.
Then, you can simply use it on the second screen.

Answer 2

In a new stateful widget where you need the textSize, do something like this
class TwoState extends StatefulWidget {
double size;
TwoState(this.size);
#override
_TwoStateState createState() => _TwoStateState(size);
}
class _TwoStateState extends State<TwoState> {
double size;
_TwoStateState(this.size);
#override
Widget build(BuildContext context) {
return Container(
child: Text("",style:TextStyle(fontSize: 25*size)),
);
}
}
And push it like
Navigator.push(context, MaterialPageRoute(builder: (context)=>TwoState(size)))
But this only works from parent to child. You can try to do something like this
Size.dart
class Sizing{
double size;
Sizing(this.size);
}
Then in the home page, create a new variable like
Sizing size = Sizing(25);
And then instead of size variable use size.size and pass it around like the previous example. This way, it will work from parent to child and from child to parent

Answer 3

auto_size_text: ^2.1.0.
AutoSizeText() instead of Text()
import 'package:auto_size_text/auto_size_text.dart';
import 'package:flutter/material.dart';
void main() {
runApp(App());
}
class App extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
body: Center(
child: SizedBox(
width: 200.0,
height: 140.0,
child: AutoSizeText(
'This string will be automatically resized to fit in two lines.',
style: TextStyle(fontSize: 30.0),
maxLines: 2,
),
),
),
),
);
}
}