ios - 验证信用卡号

Question

我正在将用户的信用卡号作为输入。我想允许 16 个数字，并希望在每 4 个数字后面格式化空格。为此，我做了以下工作。

-(void)cardNumberValidation:(id)sender{
    UITextField *temp=sender;

    if ([temp.text length]>19) {
        txtCard.text= [temp.text substringToIndex:[temp.text length] - 1];
    }
    if ([temp.text length]==4) {
        txtCard.text=[NSString stringWithFormat:@"%@ ",temp.text];

        }
    if ([temp.text length]==9) {
        txtCard.text=[NSString stringWithFormat:@"%@ ",temp.text];
        }
    if ([temp.text length]==14) {
        NSString *lastChar = [txtCard.text substringFromIndex:[txtCard.text length] - 1];
        txtCard.text=[NSString stringWithFormat:@"%@ ",temp.text];
    }
}

但是现在，当用户在输入所有字符后删除字符时，如果它达到 15 个字符，然后用户将再删除一个字符，那么此代码将在其后面添加空格，并且不允许进一步删除它。

任何人都可以给我建议或任何更好的方法来做到这一点。

Answer 1

在 swift

enum CardType: String {
    case Unknown, Amex, Visa, MasterCard, Diners, Discover, JCB, Elo, Hipercard, UnionPay

    static let allCards = [Amex, Visa, MasterCard, Diners, Discover, JCB, Elo, Hipercard, UnionPay]

    var regex : String {
        switch self {
        case .Amex:
           return "^3[47][0-9]{5,}$"
        case .Visa:
           return "^4[0-9]{6,}([0-9]{3})?$"
        case .MasterCard:
           return "^(5[1-5][0-9]{4}|677189)[0-9]{5,}$"
        case .Diners:
           return "^3(?:0[0-5]|[68][0-9])[0-9]{4,}$"
        case .Discover:
           return "^6(?:011|5[0-9]{2})[0-9]{3,}$"
        case .JCB:
           return "^(?:2131|1800|35[0-9]{3})[0-9]{3,}$"
        case .UnionPay:
           return "^(62|88)[0-9]{5,}$"
        case .Hipercard:
           return "^(606282|3841)[0-9]{5,}$"
        case .Elo:
           return "^((((636368)|(438935)|(504175)|(451416)|(636297))[0-9]{0,10})|((5067)|(4576)|(4011))[0-9]{0,12})$"
        default:
           return ""
        }
    }
}
extension UITextField{ 

func validateCreditCardFormat()-> (type: CardType, valid: Bool) {
        // Get only numbers from the input string
        var input = self.text!
        let numberOnly = input.stringByReplacingOccurrencesOfString("[^0-9]", withString: "", options: .RegularExpressionSearch)

    var type: CardType = .Unknown
    var formatted = ""
    var valid = false

    // detect card type
    for card in CardType.allCards {
        if (matchesRegex(card.regex, text: numberOnly)) {
            type = card
            break
        }
    }

    // check validity
    valid = luhnCheck(numberOnly)

    // format
    var formatted4 = ""
    for character in numberOnly.characters {
        if formatted4.characters.count == 4 {
            formatted += formatted4 + " "
            formatted4 = ""
        }
        formatted4.append(character)
    }

    formatted += formatted4 // the rest

    // return the tuple
    return (type, valid)
}

func matchesRegex(regex: String!, text: String!) -> Bool {
    do {
        let regex = try NSRegularExpression(pattern: regex, options: [.CaseInsensitive])
        let nsString = text as NSString
        let match = regex.firstMatchInString(text, options: [], range: NSMakeRange(0, nsString.length))
        return (match != nil)
    } catch {
        return false
    }
}

func luhnCheck(number: String) -> Bool {
    var sum = 0
    let digitStrings = number.characters.reverse().map { String($0) }

    for tuple in digitStrings.enumerate() {
        guard let digit = Int(tuple.element) else { return false }
        let odd = tuple.index % 2 == 1

        switch (odd, digit) {
        case (true, 9):
            sum += 9
        case (true, 0...8):
            sum += (digit * 2) % 9
        default:
            sum += digit
        }
    }

    return sum % 10 == 0
}
}

更多表格请前往http://kalapun.com/posts/card-checking-in-swift/