OTP (token) should be automatically read from the message

Question

I am working on an Android App, in which the server sends an OTP and the user needs to enter this OTP in the App, to SignUp for my App. What I want is, that my App should be

Answer 1

Sorry for late reply but still felt like posting my answer if it helps.It works for 6 digits OTP.

    @Override
    public void onOTPReceived(String messageBody)
    {
        Pattern pattern = Pattern.compile(SMSReceiver.OTP_REGEX);
        Matcher matcher = pattern.matcher(messageBody);
        String otp = HkpConstants.EMPTY;
        while (matcher.find())
        {
            otp = matcher.group();
        }
        checkAndSetOTP(otp);
    }
Adding constants here

public static final String OTP_REGEX = "[0-9]{1,6}";

For SMS listener one can follow the below class

public class SMSReceiver extends BroadcastReceiver
{
    public static final String SMS_BUNDLE = "pdus";
    public static final String OTP_REGEX = "[0-9]{1,6}";
    private static final String FORMAT = "format";

    private OnOTPSMSReceivedListener otpSMSListener;

    public SMSReceiver(OnOTPSMSReceivedListener listener)
    {
        otpSMSListener = listener;
    }

    @Override
    public void onReceive(Context context, Intent intent)
    {
        Bundle intentExtras = intent.getExtras();
        if (intentExtras != null)
        {
            Object[] sms_bundle = (Object[]) intentExtras.get(SMS_BUNDLE);
            String format = intent.getStringExtra(FORMAT);
            if (sms_bundle != null)
            {
                otpSMSListener.onOTPSMSReceived(format, sms_bundle);
            }
            else {
                // do nothing
            }
        }
    }

    @FunctionalInterface
    public interface OnOTPSMSReceivedListener
    {
        void onOTPSMSReceived(@Nullable String format, Object... smsBundle);
    }
}

    @Override
    public void onOTPSMSReceived(@Nullable String format, Object... smsBundle)
    {
        for (Object aSmsBundle : smsBundle)
        {
            SmsMessage smsMessage = getIncomingMessage(format, aSmsBundle);
            String sender = smsMessage.getDisplayOriginatingAddress();
            if (sender.toLowerCase().contains(ONEMG))
            {
                getIncomingMessage(smsMessage.getMessageBody());
            } else
            {
                // do nothing
            }
        }
    }

    private SmsMessage getIncomingMessage(@Nullable String format, Object aObject)
    {
        SmsMessage currentSMS;
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && format != null)
        {
            currentSMS = SmsMessage.createFromPdu((byte[]) aObject, format);
        } else
        {
            currentSMS = SmsMessage.createFromPdu((byte[]) aObject);
        }

        return currentSMS;
    }