Regex for determining credit cards in Android [duplicate]

Question

I'm really new to regex but I think my problem might go beyond that at the moment. As the title says, I'm trying to determine if a credit card is visa, amex, master card etc.

I looked at this post which gave the regular expression for each of the card types:

How do you detect Credit card type based on number?

This is the code I then used but it doesn't do anything at all:

etCCNum.addTextChangedListener(new TextWatcher() {
            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {



            }

            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {
                Log.d("DEBUG", "beforeTextChanged : "+s);

            }

            @Override
            public void afterTextChanged(Editable s) {
                Pattern pattern = Pattern.compile("^6(?:011|5[0-9]{2})[0-9]{3,}$");
                Log.d("DEBUG", "afterTextChanged : "+s);
                String ccNum = s.toString();
                Matcher matcher = pattern.matcher(ccNum);
               if(matcher.matches()){
                   Log.d("DEBUG", "afterTextChanged : discover");
               }

            }
        });

The regexp in the pattern.compile function is for determining Discover cards according to the post above. I've noticed that I really can't get anything to work other than the "^" in regex (i.e ("^4" - visa, "^6001" discover) however this is obviously not sufficient in the case of editing for example. Any ideas what's up? I thought this could be an issue with my Java, but I am running Java 7

I might want to make this a new question, but I am also wondering how regex can be used to get spacing correct for various credit cards even if a user goes back and edits the number (xxxx xxxx xxxx xxxx)

EDIT: Added the DEBUG log from above. My input is a few digits that should associate with certain credit cards. Currently I am using Eagle Eye's code provided below (which should also work for detecting that the input is ONE of the card types):

final ArrayList listOfPattern=new ArrayList();

String ptVisa = "^4[0-9]{6,}$";
listOfPattern.add(ptVisa);
String ptMasterCard = "^5[1-5][0-9]{5,}$";
listOfPattern.add(ptMasterCard);
String ptAmeExp = "^3[47][0-9]{5,}$";
listOfPattern.add(ptAmeExp);
String ptDinClb = "^3(?:0[0-5]|[68][0-9])[0-9]{4,}$";
listOfPattern.add(ptDinClb);
String ptDiscover = "^6(?:011|5[0-9]{2})[0-9]{3,}$";
listOfPattern.add(ptDiscover);
String ptJcb = "^(?:2131|1800|35[0-9]{3})[0-9]{3,}$";
listOfPattern.add(ptJcb);


etCCNum.addTextChangedListener(new TextWatcher() {
    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {



    }

    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
        Log.d("DEBUG", "beforeTextChanged : "+s);

    }

    @Override
    public void afterTextChanged(Editable s) {
        Log.d("DEBUG", "afterTextChanged : "+s);
        String ccNum = s.toString();
        for(String p:listOfPattern){
            if(ccNum.matches(p)){
                Log.d("DEBUG", "afterTextChanged : discover");
                break;
            }
        }

    }
});

Log:

01-29 15:16:41.932  26194-26194/com.x.x D/DEBUG﹕ beforeTextChanged :
01-29 15:16:41.933  26194-26194/com.x.x D/DEBUG﹕ afterTextChanged : 4
01-29 15:16:46.815  26194-26194/com.x.x D/DEBUG﹕ beforeTextChanged : 4
01-29 15:16:46.816  26194-26194/com.x.x D/DEBUG﹕ afterTextChanged :
01-29 15:16:50.925  26194-26194/com.x.x D/DEBUG﹕ beforeTextChanged :
01-29 15:16:50.926  26194-26194/com.x.x D/DEBUG﹕ afterTextChanged : 6
01-29 15:16:51.542  26194-26194/com.x.x D/DEBUG﹕ beforeTextChanged : 6
01-29 15:16:51.543  26194-26194/com.x.x D/DEBUG﹕ afterTextChanged : 60
01-29 15:16:51.883  26194-26194/com.x.x D/DEBUG﹕ beforeTextChanged : 60
01-29 15:16:51.883  26194-26194/com.x.x D/DEBUG﹕ afterTextChanged : 600
01-29 15:16:52.928  26194-26194/com.x.x D/DEBUG﹕ beforeTextChanged : 600
01-29 15:16:52.929  26194-26194/com.x.x D/DEBUG﹕ afterTextChanged : 6001
01-29 15:16:55.781  26194-26194/com.x.x D/DEBUG﹕ beforeTextChanged : 6001
01-29 15:16:55.782  26194-26194/com.x.x D/DEBUG﹕ afterTextChanged : 600
01-29 15:16:56.206  26194-26194/com.x.x D/DEBUG﹕ beforeTextChanged : 600
01-29 15:16:56.206  26194-26194/com.x.x D/DEBUG﹕ afterTextChanged : 60
01-29 15:16:57.659  26194-26194/com.x.x D/DEBUG﹕ beforeTextChanged : 60
01-29 15:16:57.660  26194-26194/com.x.x D/DEBUG﹕ afterTextChanged : 605
01-29 15:16:59.297  26194-26194/com.x.x D/DEBUG﹕ beforeTextChanged : 605
01-29 15:16:59.298  26194-26194/com.x.x D/DEBUG﹕ afterTextChanged : 60
01-29 15:16:59.527  26194-26194/com.x.x D/DEBUG﹕ beforeTextChanged : 60
01-29 15:16:59.527  26194-26194/com.x.x D/DEBUG﹕ afterTextChanged : 6
01-29 15:17:00.314  26194-26194/com.x.x D/DEBUG﹕ beforeTextChanged : 6
01-29 15:17:00.314  26194-26194/com.x.x D/DEBUG﹕ afterTextChanged : 65

You'd expect the log "discover" to come out a few times for the different digits I've entered. The above log shows me typing in the first few digits of a visa card and a discover card.

EDIT ANSWER FOUND: I simply wasn't typing in enough digits for the card to be recognized!

Answer 1

According to one of the answers in the thread, The cards can be validated based on following data.

Visa: ^4[0-9]{6,}$ Visa card numbers start with a 4.

MasterCard: ^5[1-5][0-9]{5,}$ MasterCard numbers start with the numbers 51 through 55, but this will only detect MasterCard credit cards; there are other cards issued using the MasterCard system that do not fall into this IIN range.

American Express: ^3[47][0-9]{5,}$ American Express card numbers start with 34 or 37.

Diners Club: ^3(?:0[0-5]|[68][0-9])[0-9]{4,}$ Diners Club card numbers begin with 300 through 305, 36 or 38. There are Diners Club cards that begin with 5 and have 16 digits. These are a joint venture between Diners Club and MasterCard, and should be processed like a MasterCard.

Discover: ^6(?:011|5[0-9]{2})[0-9]{3,}$ Discover card numbers begin with 6011 or 65.

JCB: ^(?:2131|1800|35[0-9]{3})[0-9]{3,}$ JCB cards begin with 2131, 1800 or 35.

So you need to create separate pattern for each case. You can do as follows.

ArrayList<String> listOfPattern=new ArrayList<String>();

String ptVisa = "^4[0-9]{6,}$";
listOfPattern.add(ptVisa);
String ptMasterCard = "^5[1-5][0-9]{5,}$";
listOfPattern.add(ptMasterCard);
String ptAmeExp = "^3[47][0-9]{5,}$";
listOfPattern.add(ptAmeExp);
String ptDinClb = "^3(?:0[0-5]|[68][0-9])[0-9]{4,}$";
listOfPattern.add(ptDinClb);
String ptDiscover = "^6(?:011|5[0-9]{2})[0-9]{3,}$";
listOfPattern.add(ptDiscover);
String ptJcb = "^(?:2131|1800|35[0-9]{3})[0-9]{3,}$";
listOfPattern.add(ptJcb);
}

and then,

@Override
public void afterTextChanged(Editable s) {
Log.d("DEBUG", "afterTextChanged : "+s);
String ccNum = s.toString();
   for(String p:listOfPattern){
      if(ccNum.matches(p)){
         Log.d("DEBUG", "afterTextChanged : discover");
         break;
      }
   }
}

And for your last question, The following thread should help you.

Format credit card in edit text in android

EDIT:

If the card number is 16 digits for example, After applying the logic to add spaces after 4 digits, you need to remove those spaces when you process the actual card number. Then only the above logic will work.

Hope this helps.