How to limit the textfield entry to 2 decimal places in swift 4?

Question

I have a textfield and I want to limit the entry to max 2 decimal places.

number like 12.34 is allowed but not 12.345

How do I do it?

Answer 1

None of the answers handled the decimalSeparator and all the edge cases I came across so I decided to write my own.

extension YourController: UITextFieldDelegate {
    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        guard let text = textField.text, let decimalSeparator = NSLocale.current.decimalSeparator else {
            return true
        }

         var splitText = text.components(separatedBy: decimalSeparator)
         let totalDecimalSeparators = splitText.count - 1
         let isEditingEnd = (text.count - 3) < range.lowerBound

         splitText.removeFirst()

         // Check if we will exceed 2 dp
         if
             splitText.last?.count ?? 0 > 1 && string.count != 0 &&
             isEditingEnd
         {
             return false
         }

         // If there is already a dot we don't want to allow further dots
         if totalDecimalSeparators > 0 && string == decimalSeparator {
             return false
         }

         // Only allow numbers and decimal separator
         switch(string) {
         case "", "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", decimalSeparator:
             return true
         default:
             return false
         }
     }
 }

Answer 2

In Swift 4.

TextField have 10 digit limit and after decimal 2 digit limit (you can change the Limits). The dot will allow only one time in the textField.

class ViewController: UIViewController,UITextFieldDelegate {

    var dotLocation = Int()

    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {


        let nonNumberSet = CharacterSet(charactersIn: "0123456789.").inverted

        if Int(range.length) == 0 && string.count == 0 {
            return true
        }

        if (string == ".") {
            if Int(range.location) == 0 {
                return false
            }
            if dotLocation == 0 {
                dotLocation = range.location
                return true
            } else {
                return false
            }
        }

        if range.location == dotLocation && string.count == 0 {
            dotLocation = 0
        }

        if dotLocation > 0 && range.location > dotLocation + 2 {
            return false
        }

        if range.location >= 10 {

            if dotLocation >= 10 || string.count == 0 {
                return true
            } else if range.location > dotLocation + 2 {
                return false
            }

            var newValue = (textField.text as NSString?)?.replacingCharacters(in: range, with: string)
            newValue = newValue?.components(separatedBy: nonNumberSet).joined(separator: "")
            textField.text = newValue

            return false

        } else {
            return true
        }

    }

}