ios - 为货币格式化 UITextField

Question

我的应用程序上有一个 UITextField，它只接收来自用户的数字输入。此数字输入表示货币，默认值为 0.00。

我想创建类似掩码的东西，以便在用户输入数字时格式化 UITextField。例如:

9 变成 $0,0999 变成 0,99 美元999 变成 $999,99

下面的代码运行良好，但由于我使用的是整数和浮点值，应用程序最终会在某个点后显示错误的值。例如:

999999999 变成 100000000

发生这种情况是因为 flot 和 integer 不够精确，应该使用 NSDEcimalNumber。关键是我不知道如何将我的整数和浮点值替换为 NSDecimalNumber 值。

有谁能帮我解决这个问题吗？我花了一些时间在网上搜索解决方案，但没有找到适合我需求的解决方案，而且很多人都有同样的问题。

代码如下:

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if (textField.tag == 1){
    NSString *cleanCentString = [[textField.text componentsSeparatedByCharactersInSet: [[NSCharacterSet decimalDigitCharacterSet] invertedSet]] componentsJoinedByString:@""];
    NSInteger centValue= cleanCentString.integerValue;

    if (string.length > 0)
    {
        centValue = centValue * 10 + string.integerValue;
    }
    else
    {
        centValue = centValue / 10;
    }

    NSNumber *formatedValue;
    formatedValue = [[NSNumber alloc] initWithFloat:(float)centValue / 100.0f];
    NSNumberFormatter *_currencyFormatter = [[NSNumberFormatter alloc] init];
    [_currencyFormatter setNumberStyle:NSNumberFormatterCurrencyStyle];
    textField.text = [_currencyFormatter stringFromNumber:formatedValue];
    return NO;
}

if (textField.tag == 2){
    // Nothing for now
}

return YES;
}

Answer 1

实现 UITextFieldDelegate 并添加下一个方法:

swift :

let currencySign = "$"

// Adds $ before the text, e.g. "1" -> "$1" and allows "." and ","
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool
    {
    var value = textField.text

    var newString = (textField.text as NSString).stringByReplacingCharactersInRange(range, withString: string)
    var components = newString.componentsSeparatedByCharactersInSet(NSCharacterSet(charactersInString: "1234567890,.").invertedSet)

    var decimalString = "".join(components) as NSString
    var length = decimalString.length

    if length > 0 {
        value = "\(currencySign)\(decimalString)"
    }
    else {
        value = ""
    }
    textField.text = value
}

// Formats final value using current locale, e.g. "130,50" -> "$130", "120.70" -> "$120.70", "5" -> "$5.00"
func textFieldDidEndEditing(textField: UITextField) {
        var value = textField.text
        var components = value.componentsSeparatedByCharactersInSet(NSCharacterSet(charactersInString: "1234567890,.").invertedSet)
        var decimalString = "".join(components) as NSString

        let number = NSDecimalNumber(string: decimalString, locale:NSLocale.currentLocale())

        var formatter = NSNumberFormatter()
        formatter.numberStyle = NSNumberFormatterStyle.CurrencyStyle
        formatter.locale = NSLocale.currentLocale()

        if let formatedValue = formatter.stringFromNumber(number) {
            textField.text = formatedValue
        }
        else {
            textField.text = ""
        }
}