Escribir en un EditText con formato de tarjeta de crédito

private void writeCardNumber(String number) {
    String cardNumber = "";
    for (int i = 0; i < number.length(); i++) {
        if (i % 4 == 0 && i != 0){
            cardNumber = cardNumber + " ";
        }
        cardNumber = cardNumber + number.charAt(i);
    }
    editTextCardNumber.setText(cardNumber);
}