在TextField中设置数字的间隔

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Number Input'),
        ),
        body: Center(
          child: Padding(
            padding: EdgeInsets.all(16.0),
            child: TextField(
              keyboardType: TextInputType.number,
              inputFormatters: [
                WhitelistingTextInputFormatter.digitsOnly,
                _NumberInputFormatter(),
              ],
              decoration: InputDecoration(
                labelText: 'Enter a number',
              ),
            ),
          ),
        ),
      ),
    );
  }
}

class _NumberInputFormatter extends TextInputFormatter {
  @override
  TextEditingValue formatEditUpdate(
      TextEditingValue oldValue, TextEditingValue newValue) {
    String formattedText = newValue.text.replaceAll(RegExp(r'\B(?=(\d{3})+(?!\d))'), ',');
    return newValue.copyWith(text: formattedText);
  }
}