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android - LUHN 信用卡验证在有效卡号上失败

转载 作者:搜寻专家 更新时间:2023-11-01 08:53:38 54 4
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在我的应用程序中,我想检查用户是否输入了我使用 LUHN 算法的有效卡号。我已将其创建为方法并在主 Activity 中调用。但即使我提供有效的卡号,它也会显示无效。在输入卡号时,我在中间留了空格,我不知道,因为它没有正确验证。请帮助我找出错误。

CreditcardValidation.java

public class CreditcardValidation {
String creditcard_validation,msg;
//String mobilepattern;
public static boolean isValid(long number) {

int total = sumOfDoubleEvenPlace(number) + sumOfOddPlace(number);
if ((total % 10 == 0) && (prefixMatched(number, 1) == true) && (getSize(number)>=16 ) && (getSize(number)<=19 )) {
return true;
} else {
return false;
}
}

public static int getDigit(int number) {

if (number <= 9) {
return number;
} else {
int firstDigit = number % 10;
int secondDigit = (int) (number / 10);

return firstDigit + secondDigit;
}
}
public static int sumOfOddPlace(long number) {
int result = 0;

while (number > 0) {
result += (int) (number % 10);
number = number / 100;
}

return result;
}

public static int sumOfDoubleEvenPlace(long number) {

int result = 0;
long temp = 0;

while (number > 0) {
temp = number % 100;
result += getDigit((int) (temp / 10) * 2);
number = number / 100;
}

return result;
}

public static boolean prefixMatched(long number, int d) {

if ((getPrefix(number, d) == 5)
|| (getPrefix(number, d) == 4)
|| (getPrefix(number, d) == 3)) {

if (getPrefix(number, d) == 4) {
System.out.println("\nVisa Card ");
} else if (getPrefix(number, d) == 5) {
System.out.println("\nMaster Card ");
} else if (getPrefix(number, d) == 3) {
System.out.println("\nAmerican Express Card ");
}

return true;

} else {

return false;

}
}

public static int getSize(long d) {

int count = 0;

while (d > 0) {
d = d / 10;

count++;
}

return count;

}

public static long getPrefix(long number, int k) {

if (getSize(number) < k) {
return number;
} else {

int size = (int) getSize(number);

for (int i = 0; i < (size - k); i++) {
number = number / 10;
}

return number;

}

}


public String creditcardvalidation(String creditcard)
{
Scanner sc = new Scanner(System.in);

this.creditcard_validation= creditcard;
long input = 0;
input = sc.nextLong();
//long input = sc.nextLong();
if (isValid(input) == true) {
Log.d("Please fill all the column","valid");
msg="Valid card number";

}
else{
Log.d("Please fill all the column","invalid");
msg="Please enter the valid card number";

}

return msg;
}
}


MainActivity.java

addcard.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v) {


if(v.getId()==R.id.btn_add)
{
creditcard= card_number.getText().toString();
cv = new CreditcardValidation();
String mob = cv.creditcardvalidation(creditcard);
Toast.makeText(getActivity(), mob, 1000).show();``

最佳答案

引用下面的代码

 EditText cardNumber=(EditText)findViewById(R.id.cardNumber);
String CreditCardType = "Unknown";

/// Remove all spaces and dashes from the passed string
String CardNo ="9292304336";///////cardNumber.getText().toString();
CardNo = CardNo.replace(" ", "");//removing empty space
CardNo = CardNo.replace("-", "");//removing '-'
twoDigit=Integer.parseInt(CardNo.substring(0, 2));
System.out.println("----------twoDigit--"+twoDigit);
fourDigit=Integer.parseInt(CardNo.substring(0, 4));
System.out.println("----------fourDigit--"+fourDigit);
oneDigit=Integer.parseInt(Character.toString(CardNo.charAt(0)));
System.out.println("----------oneDigit--"+oneDigit);

boolean cardValidation=false;
// 'Check that the minimum length of the string isn't <14 characters and -is- numeric
if(CardNo.length()>=14)
{

cardValidation=cardValidationMethod(CardNo);

}

boolean cardValidationMethod(String CardNo)
{
//'Check the first two digits first,for AmericanExpress
if(CardNo.length()==15 && (twoDigit==34 || twoDigit==37))
return true;
else
//'Check the first two digits first,for MasterCard
if(CardNo.length()==16 && twoDigit>=51 && twoDigit<=55)
return true;
else
//'None of the above - so check the 'first four digits collectively
if(CardNo.length()==16 && fourDigit==6011)//for DiscoverCard
return true;
else

if(CardNo.length()==16 || CardNo.length()==13 && oneDigit==4)//for VISA
return true;
else
return false;
}

你也可以引用这个演示project

关于android - LUHN 信用卡验证在有效卡号上失败,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/20897287/

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