how to get access to what textformfield shows - flutter

Question

i have textformfield i want to get access to what it shows
like when i print 10000 i want it to show and separate the int like 10,000 , i can print it with regex but i want to show it in text form field too
here us what i got in terminal (left) and what it shows in text field (right)
enter image description here
and all i wanna do is show what is in terminal to text field\
.
if you need more information please let me know
here is my code
import 'package:flutter/material.dart';
class AddTransication extends StatefulWidget {
#override
_AddTransicationState createState() => _AddTransicationState();
}
class _AddTransicationState extends State<AddTransication> {
RegExp reg_ex = new RegExp(r'(\d{1,3})(?=(\d{3})+(?!\d))');
Function mathFunc = (Match match) => '${match[1]},';
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Test Screen"),
actions: <Widget>[
FlatButton(
textColor: Colors.white,
onPressed: () {},
child: Text("Save"),
shape: CircleBorder(side: BorderSide(color: Colors.transparent)),
),
],
),
body: SafeArea(
child: Form(
child: Column(
children: [emailField(reg_ex, mathFunc)],
),
),
),
);
}
Widget emailField(reg_ex, mathFunc) {
return TextFormField(
onChanged: (str) {
String result = str.replaceAllMapped(reg_ex, mathFunc);
print(' $result');
},
keyboardType: TextInputType.emailAddress,
decoration: InputDecoration(
labelText: 'Email Address',
hintText: 'you#example.com',
),
);
}
}

Answer 1

You have to use TextEditingController class.
A controller for an editable text field.
Whenever the user modifies a text field with an associated TextEditingController, the text field updates value and the controller notifies its listeners. Listeners can then read the text and selection properties to learn what the user has typed or how the selection has been updated.
Refer : https://api.flutter.dev/flutter/widgets/TextEditingController-class.html
Please check the code, below I have updated it to work as per your question.
import 'package:flutter/material.dart';
final Color darkBlue = Color.fromARGB(255, 18, 32, 47);
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
theme: ThemeData.dark().copyWith(scaffoldBackgroundColor: darkBlue),
debugShowCheckedModeBanner: false,
home: AddTransication(),
);
}
}
class AddTransication extends StatefulWidget {
#override
_AddTransicationState createState() => _AddTransicationState();
}
class _AddTransicationState extends State<AddTransication> {
final _controller = TextEditingController();
RegExp regex = new RegExp(r'(\d{1,3})(?=(\d{3})+(?!\d))');
Function mathFunc = (Match match) => '${match[1]},';
void initState() {
super.initState();
}
void dispose() {
_controller.dispose();
super.dispose();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Test Screen"),
actions: <Widget>[
FlatButton(
textColor: Colors.white,
onPressed: () {},
child: Text("Save"),
shape: CircleBorder(side: BorderSide(color: Colors.transparent)),
),
],
),
body: SafeArea(
child: Form(
child: Column(
children: [emailField(regex, mathFunc)],
),
),
),
);
}
Widget emailField(regex, mathFunc) {
return TextFormField(
controller: _controller,
onChanged: (str) {
String text = str.replaceAll(",", "").replaceAllMapped(regex, mathFunc);
print(' $text');
_controller.value = _controller.value.copyWith(
text: text,
selection:
TextSelection(baseOffset: text.length, extentOffset: text.length),
composing: TextRange.empty,
);
},
keyboardType: TextInputType.emailAddress,
decoration: InputDecoration(
labelText: 'Email Address',
hintText: 'you#example.com',
),
);
}
}