flutter nfc_maneger package

im having issues with using the package nfc_maneger. i have used the same example code steps it showed no error but whenever i try to write on it from my phone the app crashes. could my old phone be the problem or should i look for another way?

this is the code :

the reading works fine i guess it opens a new page saying empty page so i think it fine

I'm trying to use it for taking attendance through my app so if there any sources that you can recommend me to understand the matter more. will be helpful

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

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  runApp(MyApp());
}

class MyApp extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => MyAppState();
}

class MyAppState extends State<MyApp> {
  ValueNotifier<dynamic> result = ValueNotifier(null);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: Text('NfcManager Plugin Example')),
        body: SafeArea(
          child: FutureBuilder<bool>(
            future: NfcManager.instance.isAvailable(),
            builder: (context, ss) => ss.data != true
                ? Center(child: Text('NfcManager.isAvailable(): ${ss.data}'))
                : Flex(
                    mainAxisAlignment: MainAxisAlignment.spaceBetween,
                    direction: Axis.vertical,
                    children: [
                      Flexible(
                        flex: 2,
                        child: Container(
                          margin: EdgeInsets.all(4),
                          constraints: BoxConstraints.expand(),
                          decoration: BoxDecoration(border: Border.all()),
                          child: SingleChildScrollView(
                            child: ValueListenableBuilder<dynamic>(
                              valueListenable: result,
                              builder: (context, value, _) =>
                                  Text('${value ?? ''}'),
                            ),
                          ),
                        ),
                      ),
                      Flexible(
                        flex: 3,
                        child: GridView.count(
                          padding: EdgeInsets.all(4),
                          crossAxisCount: 2,
                          childAspectRatio: 4,
                          crossAxisSpacing: 4,
                          mainAxisSpacing: 4,
                          children: [
                            ElevatedButton(
                                child: Text('Tag Read'), onPressed: _tagRead),
                            ElevatedButton(
                                child: Text('Ndef Write'),
                                onPressed: _ndefWrite),
                            ElevatedButton(
                                child: Text('Ndef Write Lock'),
                                onPressed: _ndefWriteLock),
                          ],
                        ),
                      ),
                    ],
                  ),
          ),
        ),
      ),
    );
  }

  void _tagRead() {
    NfcManager.instance.startSession(onDiscovered: (NfcTag tag) async {
      result.value = tag.data;
      NfcManager.instance.stopSession();
    });
  }

  void _ndefWrite() {
    NfcManager.instance.startSession(onDiscovered: (NfcTag tag) async {
      var ndef = Ndef.from(tag);
      if (ndef == null || !ndef.isWritable) {
        result.value = 'Tag is not ndef writable';
        NfcManager.instance.stopSession(errorMessage: result.value);
        return;
      }

      NdefMessage message = NdefMessage([
        NdefRecord.createText('Hello World!'),
        NdefRecord.createUri(Uri.parse('https://flutter.dev')),
        NdefRecord.createMime(
            'text/plain', Uint8List.fromList('Hello'.codeUnits)),
        NdefRecord.createExternal(
            'com.example', 'mytype', Uint8List.fromList('mydata'.codeUnits)),
      ]);

      try {
        await ndef.write(message);
        result.value = 'Success to "Ndef Write"';
        NfcManager.instance.stopSession();
      } catch (e) {
        result.value = e;
        NfcManager.instance.stopSession(errorMessage: result.value.toString());
        return;
      }
    });
  }

  void _ndefWriteLock() {
    NfcManager.instance.startSession(onDiscovered: (NfcTag tag) async {
      var ndef = Ndef.from(tag);
      if (ndef == null) {
        result.value = 'Tag is not ndef';
        NfcManager.instance.stopSession(errorMessage: result.value.toString());
        return;
      }

      try {
        await ndef.writeLock();
        result.value = 'Success to "Ndef Write Lock"';
        NfcManager.instance.stopSession();
      } catch (e) {
        result.value = e;
        NfcManager.instance.stopSession(errorMessage: result.value.toString());
        return;
      }
    });
  }
}