Flutter TextField正则表达式清除文本输入

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: Text('Regex TextField Example')),
        body: RegexTextFieldExample(),
      ),
    );
  }
}

class RegexTextFieldExample extends StatefulWidget {
  @override
  _RegexTextFieldExampleState createState() => _RegexTextFieldExampleState();
}

class _RegexTextFieldExampleState extends State<RegexTextFieldExample> {
  final TextEditingController _controller = TextEditingController();

  @override
  void initState() {
    super.initState();
    _controller.addListener(_applyRegex);
  }

  @override
  void dispose() {
    _controller.removeListener(_applyRegex);
    _controller.dispose();
    super.dispose();
  }

  void _applyRegex() {
    // 正则表达式匹配非数字字符
    String newText = _controller.text.replaceAll(RegExp(r'\D'), '');
    if (_controller.text != newText) {
      _controller.text = newText;
      _controller.selection = TextSelection.collapsed(offset: newText.length);
    }
  }

  @override
  Widget build(BuildContext context) {
    return Center(
      child: TextField(
        controller: _controller,
        decoration: InputDecoration(labelText: 'Enter text'),
      ),
    );
  }
}