How to format numbers in UITextField after input from custom keyboard view?

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Created Jul ’22

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My app used to rely on standard iOS Numpad Keyboard as a textField.inputView. The textField could group typed numbers (1000 -> 1 000, 50067 -> 50 067 etc) and limit the amount of numbers after the decimal point as 2 max: https://i.stack.imgur.com/69LVr.gif (GIF)

I've created a custom numpad keyboard view and implement its logic with UITextInput protocol according to that guide on StackOverflow.

I can't understand of how to deal with the code I used for grouping and limit numbers with standard iOS Numpad. Because it doesn't work properly after I type numbers from my new custom Numpad (only 2 numbers): https://i.stack.imgur.com/f3u3n.gif (GIF)

The code I use for grouping and limit numbers after decimal point in a textField:

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    let formatter = NumberFormatter()
    formatter.numberStyle = .decimal
    formatter.groupingSeparator = " "
    formatter.maximumFractionDigits = 2

    let textString = textField.text ?? ""
    guard let range = Range(range, in: string) else { return false }
    let updatedString = textString.replacingCharacters(in: range, with: string)
    let correctDecimalString = updatedString.replacingOccurrences(of: ",", with: ".")
    let completeString = correctDecimalString.replacingOccurrences(of: formatter.groupingSeparator, with: "")

    guard completeString.count <= 12 else { return false }
    guard !completeString.isEmpty else { return true }
    textField.text = completeString
    
    return string == formatter.decimalSeparator
}

Custom NumpadView:

 class NumpadView: UIView {

 var target: UITextInput?    

 init(target: UITextInput) {
     super.init(frame: .zero)
     self.target = target
     initializeSubview()
 }

 required init?(coder: NSCoder) {
     super.init(coder: coder)
     initializeSubview()
 }

 func initializeSubview() {
     let xibFileName = "NumpadView"
     let view = Bundle.main.loadNibNamed(xibFileName, owner: self, options: nil)![0] as! UIView
     self.addSubview(view)
     view.frame = self.bounds
     self.autoresizingMask = [.flexibleWidth, .flexibleHeight]
 }

 @IBAction func buttonPressed(_ sender: NumpadButton) {
     insertText((sender.titleLabel!.text)!)
 }

 func insertText(_ string: String) {
     guard let range = target?.selectedRange else { return }
     if let textField = target as? UITextField, textField.delegate?.textField?(textField, shouldChangeCharactersIn: range, replacementString: string) == false {
         return 
     }
     target?.insertText(string)
 }
}

extension UITextInput {
var selectedRange: NSRange? {
 guard let selectedRange = selectedTextRange else { return nil }
 let location = offset(from: beginningOfDocument, to: selectedRange.start)
 let length = offset(from: selectedRange.start, to: selectedRange.end)
 return NSRange(location: location, length: length)
}
}

2.How I initialize it in a VC:

override func viewDidLoad() {
    super.viewDidLoad()
    textField.delegate = self
    textField.inputView = NumpadView(target: textField)
 }

Test project on GitHub: CLICK

What should I do so the code in shouldChangeCharactersIn method work for my custom Numpad?

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