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

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;
}