Credit card number format for American express

Question

In my android app, I have this format xxxx xxxx xxxx xxxx for credit card number but when I insert AMEX with 15 digits I want it to be shown as xxxx xxxx xxxx 1234 Instead, I get xxxx xxxx xxx1 234. How do I fix this?

I'm using this code:

textCardNumber.setText("Card Number: " + mActivity.maskedAccountNumber.replaceAll("(.{4})(?!$)", "$1 "));

You should add the code you're using to display the number. – tynn Jul 27 '16 at 09:19 — tynn, Jul 27 '16 at 09:19

score 0 · Accepted Answer · answered Jul 27 '16 at 09:30

You're using a simple replace function which expects numbers of length a multiple of 4. You could just improve your formatting algorithm of course. But the most simple solution would be to assure the length of the input string.

In your specific case you could just left pad the input with an x for AMEX

String maskedAccountNumber = mActivity.maskedAccountNumber;
if (maskedAccountNumber.length() == 15)
    maskedAccountNumber = "x" + maskedAccountNumber;
textCardNumber.setText("Card Number: " + maskedAccountNumber.replaceAll("(.{4})(?!$)", "$1 "));

score 0 · Answer 2 · answered Jul 27 '16 at 09:32

0

The simplest way would be to just use -

String acc = mActivity.maskedAccountNumber;
textCardNumber.setText("Card Number: xxxx xxxx xxxx " + acc.substring(acc.length() - 4));

answered Jul 27 '16 at 09:32

prempal

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Credit card number format for American express

2 Answers2