User should not be able to delete given symbol in textfield which is a text

Question

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

I have to restrict user to delete this symbol from textfield in swift. User can delete any thing from textfield without deleting this symbol.

Answer 1

As the most probable scenario is that the Euro symbol will always be in the textfield and will be the first character, I would check if the range of characters to change is longer than 0 and starts at 0. (This will work regardless of the symbol in the first position)

func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
    if range.length>0  && range.location == 0 {
            return false
    }
    return true
}

If however, the euro symbol is not always in the text field, you could check whether the user is deleting this symbol or not by getting a reference to the string the user is changing and checking whether this contains a euro symbol:

func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
    if range.length>0  && range.location == 0 {
        let changedText = NSString(string: textField.text!).substringWithRange(range)
        if changedText.containsString("€") {
            return false
        }
    }
    return true
}