MainActivity.java

@Override
public void onNoFingerPrintHardwareFound() {
    //Device does not have finger print scanner.
}

@Override
public void onNoFingerPrintRegistered() {
    //There are no finger prints registered on this device.
}

@Override
public void onBelowMarshmallow() {
    //Device running below API 23 version of android that does not support finger print authentication.
}

@Override
public void onAuthSuccess(FingerprintManager.CryptoObject cryptoObject) {
    //Authentication sucessful.
}

@Override
public void onAuthFailed(int errorCode, String errorMessage) {
    switch (errorCode) {    //Parse the error code for recoverable/non recoverable error.
        case AuthErrorCodes.CANNOT_RECOGNIZE_ERROR:
            //Cannot recognize the fingerprint scanned.
            break;
        case AuthErrorCodes.NON_RECOVERABLE_ERROR:
            //This is not recoverable error. Try other options for user authentication. like pin, password.
            break;
        case AuthErrorCodes.RECOVERABLE_ERROR:
            //Any recoverable error. Display message to the user.
            break;
    }
}