SmsBroadcastReceiver.java

public class SmsBroadcastReceiver extends BroadcastReceiver {

  ...

  @Override
  public void onReceive(Context context, Intent intent) {
    final Bundle bundle = intent.getExtras();

    if (bundle != null) {
      final Object[] pdusObj = (Object[]) bundle.get("pdus");

      if (pdusObj != null) {
        for (Object aPdusObj : pdusObj) {

          @SuppressWarnings("deprecation") // Need to support older Android SDKs
          SmsMessage currentMessage = SmsMessage.createFromPdu((byte[]) aPdusObj);

          String senderNum = currentMessage.getDisplayOriginatingAddress();

          Matcher expectedNumberMatcher = Constants.EXPECTED_SENDER_NUMBER_PATTERN.matcher(senderNum);
          if (expectedNumberMatcher.matches()) {
            String message = currentMessage.getDisplayMessageBody();

            // Parse out the code from the message
            Matcher matcher = Constants.VERIFICATION_CODE_PATTERN.matcher(message);

            if (matcher.matches()) {
                codeReceivedListener.onVerificationCodeReceived(matcher.group(1)); // group 1 is the first group extracted from the entire match
            }
          }
        }
      }
    }
  }
  
  ...
    
}