xcode swift - formatting text as phone number [duplicate]

Question

This question already has answers here:

UITextField for Phone Number (24 answers)

Closed 4 years ago.

I'm creating an iPhone app using Swift. I'm trying to setup a textfield in which the user can enter a phone number that automatically becomes formatted EXACTLY like it does in the built-in Contacts app as it is typed. I'm hoping xcode has built-in methods for doing this.

As an alternative, I created my own code that would add and delete brackets, dashes, etc as the user types and backspaces, but this quickly became problematic if the user was to move the curser away from the end of the entered text. In the Contacts app, if the cursor is moved just after a bracket and the user hits backspace, it deletes not just the bracket but rather the number preceding it. I'm not sure if this is done with some built-in formatting method or if perhaps there is code that replicates the text shown with brackets, dashes, etc removed and reads the position of the cursor, then calculates what the new string should be, and adds new brackets, dashes, etc.

Specifically, I'd like to know:

1) Is there a built-in method to format text to look like a phone number exactly as is done in the Contacts app?

2) If there is no built-in method, can someone tell me how I can have Swift read in the cursor position?

Thanks!

Answer 1

There is no built-in way to do this. Here's one implementation that uses the UITextField's shouldChangeCharactersInRange method:

func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool
{
    if textField == phoneTextField
    {
        var newString = (textField.text as NSString).stringByReplacingCharactersInRange(range, withString: string)
        var components = newString.componentsSeparatedByCharactersInSet(NSCharacterSet.decimalDigitCharacterSet().invertedSet)

        var decimalString = "".join(components) as NSString
        var length = decimalString.length
        var hasLeadingOne = length > 0 && decimalString.characterAtIndex(0) == (1 as unichar)

        if length == 0 || (length > 10 && !hasLeadingOne) || length > 11
        {
            var newLength = (textField.text as NSString).length + (string as NSString).length - range.length as Int

            return (newLength > 10) ? false : true
        }
        var index = 0 as Int
        var formattedString = NSMutableString()

        if hasLeadingOne
        {
            formattedString.appendString("1 ")
            index += 1
        }
        if (length - index) > 3
        {
            var areaCode = decimalString.substringWithRange(NSMakeRange(index, 3))
            formattedString.appendFormat("(%@)", areaCode)
            index += 3
        }
        if length - index > 3
        {
            var prefix = decimalString.substringWithRange(NSMakeRange(index, 3))
            formattedString.appendFormat("%@-", prefix)
            index += 3
        }

        var remainder = decimalString.substringFromIndex(index)
        formattedString.appendString(remainder)
        textField.text = formattedString
        return false
    }
    else
    {
        return true
    }
}

As previously answered in this thread: UITextField for Phone Number