Cursor shifts to end on edit of formatted decimal textfield - Swift - swift

Question

I am formatting a UITextField such that it becomes comma separated (Decimal style) while typing.
So 12345678 becomes 12,345,678
Now when I edit the UITextField, say I want to remove 5, at that time I tap after 5 and delete it but the cursor shifts to the end of the text immediately, that's after 8.
Here's my code which I have used to format the decimal while typing:
func checkTextField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
if ((string == "0" || string == "") && (textField.text! as NSString).range(of: ".").location < range.location) {
return true
}
let allowedCharacterSet = NSCharacterSet(charactersIn: "0123456789.").inverted
let filtered = string.components(separatedBy: allowedCharacterSet)
let component = filtered.joined(separator: "")
let isNumeric = string == component
if isNumeric {
let formatter = NumberFormatter()
formatter.numberStyle = .decimal
let newString = (textField.text! as NSString).replacingCharacters(in: range, with: string)
let numberWithOutCommas = newString.replacingOccurrences(of: ",", with: "")
let number = formatter.number(from: numberWithOutCommas)
if number != nil {
var formattedString = formatter.string(from: number!)
if string == "." && range.location == textField.text?.count {
formattedString = formattedString?.appending(".")
}
textField.text = formattedString
} else {
textField.text = nil
}
}
return false
}
It is called like this:
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let textFieldText = (textField.text! as NSString).replacingCharacters(in: range, with: string)
let checkForCurrency = checkTextField(textField, shouldChangeCharactersIn: range, replacementString: string)
return checkForCurrency
}
I have tried the following but in vain :
Solution 1
Solution 2
What could the reason for cursor shift be?
It should be something like in this link
Any help would be appreciated!

Answer 1

update your custom function with :
func checkTextField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let textFieldText = (textField.text! as NSString).replacingCharacters(in: range, with: string)
if ((string == "0" || string == "") && (textField.text! as NSString).range(of: ".").location < range.location) {
return true
}
var currentPosition = 0
if let selectedRange = textField.selectedTextRange {
currentPosition = textField.offset(from: textField.beginningOfDocument, to: selectedRange.start)
}
let allowedCharacterSet = NSCharacterSet(charactersIn: "0123456789.").inverted
let filtered = string.components(separatedBy: allowedCharacterSet)
let component = filtered.joined(separator: "")
let isNumeric = string == component
if isNumeric {
let formatter = NumberFormatter()
formatter.numberStyle = .decimal
let newString = (textField.text! as NSString).replacingCharacters(in: range, with: string)
let numberWithOutCommas = newString.replacingOccurrences(of: ",", with: "")
let number = formatter.number(from: numberWithOutCommas)
if number != nil {
var formattedString = formatter.string(from: number!)
if string == "." && range.location == textField.text?.count {
formattedString = formattedString?.appending(".")
}
textField.text = formattedString
if(textFieldText.count < formattedString?.count ?? 0){
currentPosition = currentPosition + 1
}
}else{
textField.text = nil
}
}
if(string == ""){
currentPosition = currentPosition - 1
}else{
currentPosition = currentPosition + 1
}
if let newPosition = textField.position(from: textField.beginningOfDocument, offset: currentPosition) {
textField.selectedTextRange = textField.textRange(from: newPosition, to: newPosition)
}
return false
}