[英]How can I validate Credit Card/Check Card Number?
I am making a custom view that checks valid card number.我正在制作一个检查有效卡号的自定义视图。 This is how I validate the card number.这就是我验证卡号的方式。
boolean validateNumber(CharSequence number) {
// This is for an exception.
if(number.toString().startsWith("941082")) return true;
int sum = 0;
final int size = number.length();
final int checkDigit = number.charAt(size - 1) - '0';
boolean doubleDigit = true;
for (int index = size - 1; --index >= 0; doubleDigit = !doubleDigit) {
int digit = number.charAt(index) - '0';
if (doubleDigit) {
digit *= 2;
if (digit > 9) {
//sum the two digits together,
//the first is always 1 as the highest
// double will be 18
digit = 1 + (digit % 10);
}
}
sum += digit;
}
return ((sum + checkDigit) % 10) == 0;
}
But rarely, some cards aren't passed.但很少有一些牌没有通过。 How can I solve this issue?我该如何解决这个问题?
source: https://www.ksnet.co.kr/Bbs?ci=NOTICE&c=NOTICE&fi=&fw=&f=ALL&q=BIN来源: https://www.ksnet.co.kr/Bbs?ci=NOTICE&c=NOTICE&fi=&fw=&f=ALL&q=BIN
The source provides BINs.源提供 BIN。 However, even after them, card has more numbers and they are not valid somtimes with the function.但是,即使在它们之后,卡也有更多的数字,并且它们有时对 function 无效。 How can I check those exception card numbers?我怎样才能检查那些例外卡号? (It's more than 3000 cases) (超过3000例)
Those problems were caused mostly in Domestic(Korean) Card that starts with 9.这些问题主要是在以 9 开头的国内(韩国)卡中引起的。
I`m using Kotlin Language我正在使用 Kotlin 语言
private fun checksum(input: String) = addends(input).sum()
private fun addends(input: String) = input.digits().mapIndexed { i, j ->
when {
(input.length - i + 1) % 2 == 0 -> j
j >= 5 -> j * 2 - 9
else -> j * 2
}
}
And Finally You using Function isValidCard最后你使用 Function isValidCard
fun isValidCard(input: String): Boolean {
val sanitizedInput = input.replace(" ", "")
return when {
valid(sanitizedInput) -> checksum(sanitizedInput) % 10 == 0
else -> false
}
}
This working for me.这对我有用。
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