How to properly format currency on ios

Question

I\'m looking for a way to format a string into currency without using the TextField hack.

For example, i\'d like to have the number \"521242\" converted into \"5,212

Answer 1

I use this code. This work for me

1) Add UITextField Delegate to header file

2) Add this code (ARC enabled)

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {

NSString *cleanCentString = [[textField.text
                              componentsSeparatedByCharactersInSet:
                              [[NSCharacterSet decimalDigitCharacterSet] invertedSet]]
                             componentsJoinedByString:@""];
// Parse final integer value
NSInteger centAmount = cleanCentString.integerValue;
// Check the user input
if (string.length > 0)
{
    // Digit added
    centAmount = centAmount * 10 + string.integerValue;
}
else
{
    // Digit deleted
    centAmount = centAmount / 10;
}
// Update call amount value
NSNumber *amount = [[NSNumber alloc] initWithFloat:(float)centAmount / 100.0f];
// Write amount with currency symbols to the textfield
NSNumberFormatter *_currencyFormatter = [[NSNumberFormatter alloc] init];
[_currencyFormatter setNumberStyle:NSNumberFormatterCurrencyStyle];
[_currencyFormatter setCurrencyCode:@"USD"];
[_currencyFormatter setNegativeFormat:@"-¤#,##0.00"];
textField.text = [_currencyFormatter stringFromNumber:amount];
return NO; }

Answer 2

swift 2.0 version:

    let _currencyFormatter : NSNumberFormatter = NSNumberFormatter()
    _currencyFormatter.numberStyle = NSNumberFormatterStyle.CurrencyStyle
    _currencyFormatter.currencyCode = "EUR"
    textField.text = _currencyFormatter.stringFromNumber(amount);

Answer 3

You probably want something like this (assuming currency is a float):

NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];
[numberFormatter setNumberStyle: NSNumberFormatterCurrencyStyle];
NSString *numberAsString = [numberFormatter stringFromNumber:[NSNumber numberWithFloat:currency]];

From your requirements to treat 52 as .52 you may need to divide by 100.0.

The nice thing about this approach is that it will respect the current locale. So, where appropriate it will format your example as "5.212,42".

Update: I was, perhaps, a little speedy in posting my example. As pointed out by Conrad Shultz below, when dealing with currency amounts, it would be preferable to store the quantities as NSDecimalNumbers. This will greatly reduce headaches with rounding errors. If you do this the above code snippet becomes (assuming currency is a NSDecimalNumber*):

NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];
[numberFormatter setNumberStyle: NSNumberFormatterCurrencyStyle];
NSString *numberAsString = [numberFormatter stringFromNumber:currency];

Answer 4

For Swift tested code (ref from AAV's code)

func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool{

    let strMain : NSString = string

    let arrTemp : NSArray = (textField.text?.componentsSeparatedByCharactersInSet(NSCharacterSet.decimalDigitCharacterSet().invertedSet))!
    let str: NSString = arrTemp.componentsJoinedByString("")

    //NSInteger centAmount = cleanCentString.integerValue;
    var centAmount : NSInteger = str.integerValue

    if (string.length > 0)
    {
        // Digit added
        centAmount = centAmount * 10 + strMain.integerValue;
    }
    else {
        // Digit deleted
        centAmount = centAmount / 10;
    }

    let amount = (Double(centAmount) / 100.0)

    let currencyFormatter = NSNumberFormatter()
    currencyFormatter.numberStyle = .CurrencyStyle
    currencyFormatter.currencyCode = "USD"
    currencyFormatter.negativeFormat = "-¤#,##0.00"
    let convertedPrice = currencyFormatter.stringFromNumber(amount)

    print(convertedPrice)

    txtAmount.text = convertedPrice! //set text to your textfiled
    return false //return false for exact out put
}

note : if you want to remove the default currency symbol from input you can use currencySymbol to blank as below

currencyFormatter.currencyCode = nil
currencyFormatter.currencySymbol = ""

Happy coding!

Answer 5

func getCurrencyFormat(price:String)->String{
    let convertPrice = NSNumber(double: Double(price)!)
    let formatter = NSNumberFormatter()
    formatter.numberStyle = .CurrencyStyle
    formatter.currencyCode = "USD"        

    let convertedPrice = formatter.stringFromNumber(convertPrice)       
    return convertedPrice!
}

Note:- A currency code is a three-letter code that is, in most cases, composed of a country’s two-character Internet country code plus an extra character to denote the currency unit. For example, the currency code for the Australian dollar is “AUD”.

Answer 6

This is what I have found reworking AAV answer using NSDecimalNumbers.

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {

NSString *cleanCentString = [[textField.text
                              componentsSeparatedByCharactersInSet:
                              [[NSCharacterSet decimalDigitCharacterSet] invertedSet]]
                             componentsJoinedByString:@""];


// Parse final integer value
NSDecimalNumber *price = [NSDecimalNumber decimalNumberWithMantissa:[cleanCentString integerValue]
                                                           exponent:-2
                                                         isNegative:NO];

NSDecimalNumber *entry = [NSDecimalNumber decimalNumberWithMantissa:[string integerValue]
                                                           exponent:-2
                                                         isNegative:NO];

NSDecimalNumber *multiplier = [NSDecimalNumber decimalNumberWithMantissa:1
                                                            exponent:1
                                                          isNegative:NO];

NSDecimalNumberHandler *handler = [NSDecimalNumberHandler decimalNumberHandlerWithRoundingMode:NSRoundPlain
                                                                                         scale:2
                                                                              raiseOnExactness:NO
                                                                               raiseOnOverflow:NO
                                                                              raiseOnUnderflow:NO
                                                                           raiseOnDivideByZero:NO];
NSDecimalNumber *result;

// Check the user input
if (string.length > 0)
{
    // Digit added
    result = [price decimalNumberByMultiplyingBy:multiplier withBehavior:handler];
    result = [result decimalNumberByAdding:entry];
}
else
{
    // Digit deleted
    result = [price decimalNumberByDividingBy:multiplier withBehavior:handler];
}

// Write amount with currency symbols to the textfield
NSNumberFormatter *_currencyFormatter = [[NSNumberFormatter alloc] init];
[_currencyFormatter setNumberStyle:NSNumberFormatterCurrencyStyle];
[_currencyFormatter setCurrencyCode:@"USD"];
textField.text = [_currencyFormatter stringFromNumber:result];

return NO;
}