In today's world, RFID (Radio-Frequency Identification) technology is widely used for various applications like access control, inventory management, and contactless payments. In this blog post, we will explore how to read RFID cards in Android devices using NFC (Near Field Communication) technology.

Prerequisites

Before we begin, ensure that your Android device supports NFC and your project has the necessary permissions to access NFC functionality. You will also need an RFID reader compatible with Android devices, which supports NFC communication.

Step 1: Set Up Project Dependencies

Open your Android project in Android Studio and navigate to the Gradle file. Add the following dependency to your app-level build.gradle file:

    
dependencies {
  implementation 'com.android.support:appcompat-v7:28.0.0'
  implementation 'com.android.support:support-v4:28.0.0'
  implementation 'com.github.skjolber:nfc-reader-library:2.1.1'
}
    
  

Step 2: Initialize NFC Adapter

In your Android activity or fragment, initialize the NFC adapter and check if it's available:

    
NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
if (nfcAdapter == null) {
  // NFC is not supported on this device
  return;
}
    
  

Step 3: Handle NFC Intent

Override the onNewIntent method in your activity or fragment to handle NFC intents:

    
@Override
protected void onNewIntent(Intent intent) {
  super.onNewIntent(intent);
  if (NfcAdapter.ACTION_TAG_DISCOVERED.equals(intent.getAction())) {
    // NFC tag discovered, handle the data
    Tag tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
    // Read the RFID card data from the tag and process it
    // ...
  }
}
    
  

Step 4: Read RFID Card Data

To read the RFID card data, we need to convert the tag data to a readable format. Add the following method to your activity or fragment:

    
private String readRFIDCardData(Tag tag) {
  Ndef ndef = Ndef.get(tag);
  if (ndef == null) {
    // Tag is not formatted as NDEF
    // You can implement different logic based on the tag type
    return null;
  }
  
  NdefMessage ndefMessage = ndef.getCachedNdefMessage();
  if (ndefMessage == null) {
    // NDEF message not found
    return null;
  }
  
  // Read the records from the NDEF message
  NdefRecord[] records = ndefMessage.getRecords();
  StringBuilder sb = new StringBuilder();
  
  for (NdefRecord record : records) {
    byte[] payload = record.getPayload();
    
    // Skip the first byte (usually the language code)
    for (int i = 1; i < payload.length; i++) {
      sb.append((char) payload[i]);
    }
  }
  
  return sb.toString();
}
    
  

Step 5: Request NFC Foreground Dispatch

To receive NFC intents when your app is in the foreground, you need to request foreground dispatch. Add the following code to your activity or fragment:

    
@Override
protected void onResume() {
  super.onResume();
  IntentFilter intentFilter = new IntentFilter(NfcAdapter.ACTION_TAG_DISCOVERED);
  PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, new Intent(this, getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);
  nfcAdapter.enableForegroundDispatch(this, pendingIntent, new IntentFilter[] { intentFilter }, null);
}

@Override
protected void onPause() {
  super.onPause();
  nfcAdapter.disableForegroundDispatch(this);
}
    
  

Step 6: Process RFID Card Data

Finally, you can process the read RFID card data as per your application requirements. You can display it to the user, store it in a database, or perform any other desired actions.

Conclusion

Reading RFID cards in Android using NFC technology is not complex with the right tools and knowledge. By following the steps outlined in this blog post, you should now have a good understanding of how to read RFID cards in your Android application. Remember to handle errors gracefully and consider the security aspects of handling sensitive RFID card data.