Escribir en un EditText tipo tarjeta de crédito

public class TarjetaCredito {
    public void writeCreditCard(EditText editText, String card){
        String cardAux = "";
        int j = 1;
        for (int i = 0; i < card.length() ; i++) {
            if(j == 5){
                cardAux += card.charAt(i) + " ";
                j = 1;
            }else {
                cardAux += card.charAt(i);
                j++;
            }
        }

        editText.setText(cardAux);
    }
}