PaymentActivity.java

package com.mobile.emvpay;

import android.app.PendingIntent;
import android.content.Intent;
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.nfc.tech.IsoDep;
import android.os.Bundle;

import androidx.appcompat.app.AppCompatActivity;

import java.io.IOException;

public class PaymentActivity extends AppCompatActivity {

    private NfcAdapter nfcAdapter;
    private PendingIntent pendingIntent;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.payment_activity);

        nfcAdapter = NfcAdapter.getDefaultAdapter(this);
        pendingIntent = PendingIntent.getActivity(this, 0, new Intent(this, getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);
    }

    @Override
    protected void onResume() {
        super.onResume();
        if (nfcAdapter != null) {
            nfcAdapter.enableForegroundDispatch(this, pendingIntent, null, null);
        }
    }

    @Override
    protected void onPause() {
        super.onPause();
        if (nfcAdapter != null) {
            nfcAdapter.disableForegroundDispatch(this);
        }
    }

    @Override
    protected void onNewIntent(Intent intent) {
        super.onNewIntent(intent);

        Tag tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
        if (tag != null) {
            IsoDep isoDep = IsoDep.get(tag);
            if (isoDep != null) {
                // Process the payment card with IsoDep
                processPaymentCard(isoDep);
            }
        }
    }

    private void processPaymentCard(IsoDep isoDep) {
        try {
            isoDep.connect();

            // PPSE command
            byte[] ppseCommand = {
                    // Your PPSE command bytes
            };
            byte[] ppseResponse = isoDep.transceive(ppseCommand);

            // Parse the response and extract AID

            // SELECT AID command
            byte[] selectAidCommand = {
                    // Your SELECT AID command bytes with the extracted AID
            };
            byte[] selectAidResponse = isoDep.transceive(selectAidCommand);

            // GPO command
            byte[] gpoCommand = {
                    // Your GPO command bytes
            };
            byte[] gpoResponse = isoDep.transceive(gpoCommand);

            // Process the GPO response

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                isoDep.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}