Escribir en un EditText con formato de tarjeta de crédito

public static void formatCreditCard(StringBuilder stringBuilder, char c, int index) {
        if (stringBuilder == null)
            return;

        if (index < 0 || index > stringBuilder.length())
            return;

        if (index == 0 || index == 4 || index == 8 || index == 12) {
            stringBuilder.insert(index, c);
        } else if (index == stringBuilder.length() - 1) {
            if (index == 3 || index == 7 || index == 11 || index == 15) {
                stringBuilder.insert(index, c);
            }
        } else {
            if (index == 3) {
                stringBuilder.insert(index, ' ');
                stringBuilder.insert(index + 1, c);
            } else if (index == 7) {
                stringBuilder.insert(index, ' ');
                stringBuilder.insert(index + 1, c);
            } else if (index == 11) {
                stringBuilder.insert(index, ' ');
                stringBuilder.insert(index + 1, c);
            }