Format a UITextField for currency

Question

I have a UITextField on my aplication that receives only numeric input from the user. This numeric input represents currency and have the default value of 0.00.

I wo

Answer 1

Implement UITextFieldDelegate and add next methods:

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 = ""
        }
}