How to add a grouping separator while user is typing a number into UITextField? - swift

Question

I am doing a currency type UITextField. The behavior I need is like this:
I managed to create the decimal part. But I have problems adding in the grouping separators for thousands. How do I group the integer part here?
Here is the code so far:
import UIKit
class ViewController: UIViewController, UITextFieldDelegate {
#IBOutlet weak var textField: UITextField!
let DIGITS = ["0","1","2","3","4","5","6","7","8","9","0"]
let DECIMAL_SEPERATOR = ","
let THOUSAND_SEPERATOR = "."
let DECIMAL_DIGITS = 2
let DECIMAL_DIGITS_DEFAULT_STRING = "00"
override func viewDidLoad() {
super.viewDidLoad()
textField.delegate = self
textField.text = "0\(DECIMAL_SEPERATOR)\(DECIMAL_DIGITS_DEFAULT_STRING)"
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
//Textfield
func textFieldTriggerDone(){
if !textField.text!.containsString(DECIMAL_SEPERATOR){
textField.text = textField.text! + DECIMAL_SEPERATOR + DECIMAL_DIGITS_DEFAULT_STRING
}
print("Add missing parts here")
}
func textFieldTriggerDecimalTyped(){
textField.text = textField.text! + DECIMAL_SEPERATOR
}
func textFieldShouldAddNumber(text: String, range: NSRange, replacement: String, dots: Int) -> Bool{
let nsstring = NSString(string: text)
let decimalRange = nsstring.rangeOfString(DECIMAL_SEPERATOR)
if range.location > decimalRange.location{
let parts = text.componentsSeparatedByString(DECIMAL_SEPERATOR)
if parts.count > 1{
if parts[1].characters.count > (DECIMAL_DIGITS-1){
return false
}
}
}else if range.location < decimalRange.location{
if textField.text!.characters.count == 1 && textField.text! == "0"{
textField.text = replacement
return false
}else{
let insertIndex = text.startIndex.advancedBy(range.location-dots)
var finalText = text
if replacement.characters.count > 0 {
finalText.insert(replacement.characters.first!, atIndex: insertIndex)
textField.text = finalText
let begin = textField.beginningOfDocument
let pos = textField.positionFromPosition(begin, offset: (range.location+1))
let cursorpos = textField.textRangeFromPosition(pos!, toPosition: pos!)
textField.selectedTextRange = cursorpos
//textFieldAddThousandSeperators()
return false
}
}
}
return true
}
func textFieldShouldReturn(textField: UITextField) -> Bool {
textField.resignFirstResponder()
return true
}
func textFieldDidEndEditing(textField: UITextField) {
textFieldTriggerDone()
}
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
let dots = textField.text!.occurancesOf(THOUSAND_SEPERATOR)
if string == ""{
if textField.text!.characters.count > 1{
return true
}else{
textField.text! = "0"
return false
}
}
if range.location == 0 && string == "0"{
return false
}
if DIGITS.contains(string){
return textFieldShouldAddNumber(textField.text!, range: range, replacement: string, dots: dots)
}
if string == DECIMAL_SEPERATOR || string == THOUSAND_SEPERATOR{
if textField.text!.containsString(DECIMAL_SEPERATOR){
return false
}
textFieldTriggerDecimalTyped()
return false
}
return false
}
}

Answer 1

Check out this answer:
https://stackoverflow.com/a/40469426/6863743
code:
override func viewDidLoad() {
super.viewDidLoad()
textField.addTarget(self, action: #selector(myTextFieldDidChange), for: .editingChanged)
}
func myTextFieldDidChange(_ textField: UITextField) {
if let amountString = textField.text?.currencyInputFormatting() {
textField.text = amountString
}
}
extension String {
// formatting text for currency textField
func currencyInputFormatting() -> String {
var number: NSNumber!
let formatter = NumberFormatter()
formatter.numberStyle = .currencyAccounting
formatter.currencySymbol = "$"
formatter.maximumFractionDigits = 2
formatter.minimumFractionDigits = 2
var amountWithPrefix = self
// remove from String: "$", ".", ","
let regex = try! NSRegularExpression(pattern: "[^0-9]", options: .caseInsensitive)
amountWithPrefix = regex.stringByReplacingMatches(in: amountWithPrefix, options: NSRegularExpression.MatchingOptions(rawValue: 0), range: NSMakeRange(0, self.characters.count), withTemplate: "")
let double = (amountWithPrefix as NSString).doubleValue
number = NSNumber(value: (double / 100))
// if first number is 0 or all numbers were deleted
guard number != 0 as NSNumber else {
return ""
}
return formatter.string(from: number)!
}
}
To get it to convert back to something you can do calculations with, you can just write a function to take out the "," and "." and so on.
Hope this helps a bit, it's the best solution I've found for currency formatting.