private void onKeyPress() {
        if (txtFirstName.getText().isEmpty() || txtLastName.getText().isEmpty() || txtAddress.getText().isEmpty()
                || txtPhone.getText().isEmpty() || txtPaymentNo.getText().isEmpty()) {
            btnSave.setEnabled(false);
        } else {
            btnSave.setEnabled(true);
        }
        if (!(txtPhone.getText().isEmpty())) {
            if (!checkForIntegers(txtPhone.getText())) {
                txtPhone.setText(MessageDialog.getInstance().emptyString());
                MessageDialog.getInstance().noTextHere();
            }
        }
        if (!(txtPaymentNo.getText().isEmpty())) {
            if (!checkForIntegers(txtPaymentNo.getText())) {
                txtPaymentNo.setText(MessageDialog.getInstance().emptyString());
                MessageDialog.getInstance().noTextHere();
            }
        }
    }