How to Create a NFC Reader and Writer Flutter Application

 NfcManager.instance.isAvailable().then((isAvailable) {
    if (isAvailable) {
        print("availble"); // Start NFC session if available
    } else {
        print("unavailble"); // Show error message if NFC is not available
      }
});

// Function to read NFC tag
void _readNfcTag() {
    //Start NFC session
    NfcManager.instance.startSession(onDiscovered: (NfcTag tag) async {
      Ndef? ndef = Ndef.from(tag);
      if (ndef != null) {
        // Read message from tag
        NdefMessage? message = await ndef.read(); 
        //Code to Store the fetched data from tag
        ....
      }
      // Stop NFC session
      NfcManager.instance.stopSession(); 
    });
  }

void _writeNfcTag() {
    // Start NFC session
    NfcManager.instance.startSession(onDiscovered: (NfcTag tag) async {
      // Example of writing data to the tag
      Ndef? ndef = Ndef.from(tag);
      if (ndef != null && ndef.isWritable) {
        // Create NDEF message with input text
        NdefMessage message = NdefMessage([
          NdefRecord.createText(String_data), 
        ]);
        // Write message to tag
        await ndef.write(message); 
      }
      // Stop NFC session
      NfcManager.instance.stopSession(); 
    });
}

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

void main() {
    
  // Start the app
  runApp(const MyApp()); 
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false, // Hide the debug banner
      home: NfcScreen(), // Set the home screen to BitCoinTracker
    );
  }
}

// Main class for the NFC screen
class NfcScreen extends StatefulWidget {
  @override
  _NfcScreenState createState() => _NfcScreenState();
}

// State class for the NFC screen
class _NfcScreenState extends State<NfcScreen> {
  // Variable to store NFC data
  String _nfcData = 'No data'; 
  
  // Controller for text input
  final TextEditingController _textController = TextEditingController(); 
  
  @override
  void initState() {
    super.initState();
    
    // Check if NFC is available
    NfcManager.instance.isAvailable().then((isAvailable) {
      if (isAvailable) {
        // Start NFC session if available
      } 
      else {
        setState(() {
            
           // Update UI if NFC is not available
           _nfcData = 'NFC is not available'; 
        });
      }
    });
  }

  // Function to start NFC session
  void _writeNfcTag() {
      
    // Start NFC session
    NfcManager.instance.startSession(onDiscovered: (NfcTag tag) async {
      
      // Example of writing data to the tag
      Ndef? ndef = Ndef.from(tag);
      
      if (ndef != null && ndef.isWritable) {
        
        // Create NDEF message with input text
        NdefMessage message = NdefMessage([
          NdefRecord.createText(_textController.text),
        ]);
        try {
          // Write message to tag
          await ndef.write(message);
          setState(() {
              // Update UI on success
              _nfcData = 'Write successful!'; 
          });
        } catch (e) {
          setState(() {
              // Update UI on failure
              _nfcData = 'Write failed: $e'; 
          });
        }
      }
      
      // Stop NFC session
      NfcManager.instance.stopSession();
    });
  }

  // Function to read NFC tag
  void _readNfcTag() {
    NfcManager.instance.startSession(onDiscovered: (NfcTag tag) async {
      Ndef? ndef = Ndef.from(tag);
      if (ndef != null) {
        // Read message from tag
        NdefMessage? message = await ndef.read();
        
        setState(() {
            
          // Store payload in temp variable
          var rawData = message.records.first.payload; 
          
          // Convert payload to string
          String textData = String.fromCharCodes(rawData); 
          
          // Update UI with read data
          _nfcData = textData.substring(3); 
        });
      }
      
      // Stop NFC session
      NfcManager.instance.stopSession();
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('NFC Screen'), // App bar title
      ),
      body: Padding(
        padding: const EdgeInsets.all(20),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            TextField(
              controller: _textController,
              decoration: InputDecoration(
                labelText: 'Enter data to write', // Input field label
              ),
            ),
            ElevatedButton(
              onPressed: _writeNfcTag,
              child: Text('Write to NFC'), // Button to write to NFC
            ),
            ElevatedButton(
              onPressed: _readNfcTag,
              child: Text('Read from NFC'), // Button to read from NFC
            ),
            SizedBox(height: 20),
            Text(_nfcData), // Display NFC data
          ],
        ),
      ),
    );
  }
}