sliding_text_field_error

main.dart

import 'dart:math';

import 'package:flutter/material.dart';

void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key}) : super(key: key);

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Persistence Example'),
      ),
      body: const ColorBoxPage(
        key: PageStorageKey<String>('pageTwo'),
      ),
    );
  }
}

class ColorBoxPage extends StatelessWidget {
  const ColorBoxPage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return ListView.builder(
        itemExtent: 100.0,
        itemBuilder: (BuildContext context, int index) {
          final rnd = Random().nextInt(34532);
          return TxtField('$rnd', key: ValueKey('$index'));
        });
  }
}

class TxtField extends StatefulWidget {
  final String initialValue;
  const TxtField(this.initialValue, {Key? key}) : super(key: key);

  @override
  State<TxtField> createState() => _MyWidgetState();
}

class _MyWidgetState extends State<TxtField> {
  late final TextEditingController _controller;

  @override
  void initState() {
    _controller = TextEditingController(text: widget.initialValue);
    super.initState();
  }

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

  @override
  Widget build(BuildContext context) {
    return TextField(
      controller: _controller,
    );
  }
}