pt-Br-cellPhoneMask.swift

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        
        if textField == cellPhoneTextField {
            
            let newString = (textField.text! as NSString).replacingCharacters(in: range, with: string)
            let components = (newString as NSString).components(separatedBy: NSCharacterSet.decimalDigits.inverted)
            
            let decimalString = components.joined(separator: "") as NSString
            let length = decimalString.length
            
            if length == 0 || length > 11 {
                let newLength = (textField.text! as NSString).length + (string as NSString).length - range.length as Int
                
                return (newLength > 11) ? false : true
            }
            var index = 0 as Int
            var formattedString = ""
            if (length - index) > 2 {
                let areaCode = decimalString.substring(with: NSMakeRange(index, 2))
                formattedString.append("(\(areaCode))")
                index += 2
            }
            if length == 10 {
                if length - index > 4 {
                    let prefix = decimalString.substring(with: NSMakeRange(index, 4))
                    formattedString.append("\(prefix)-")
                    index += 4
                }
            } else if length == 11 {
                if length - index > 5 {
                    let prefix = decimalString.substring(with: NSMakeRange(index, 5))
                    formattedString.append("\(prefix)-")
                    index += 5
                }
            }
            
            let remainder = decimalString.substring(from: index)
            formattedString.append(remainder)
            textField.text = formattedString
            return false
            
        } else {
            return true
        }
    }