moving decimal point as I enter the input to textfield in swift

Question

I want to enter currency in text field. But I would like to move decimal point after entering each number. For example

default value is $0.00 when I enter 2 then it should show $0.02 after I enter 4 then it show $0.24 after I enter 9 then it should show $2.49 after I enter 9 then it should show $24.99

Currently I am trying to update textfield on Editing Changed as follows

@IBAction func currencyTapped(sender: UITextField) {

    let formatter = NSNumberFormatter()

    formatter.minimumIntegerDigits = 1

    formatter.minimumFractionDigits = 2

    formatter.maximumFractionDigits = 2

    formatter.usesGroupingSeparator = true

    if let str = sender.text {

        if let num = Double(str) {

            sender.text = formatter.stringFromNumber(num)

        }

    }

}

How do I change to code to enter value as I want?

It might be easier to treat the entered number as cents and divide it by 100 when displaying it — vadian, Jan 10 '16 at 09:30
I tried that approach. It works fine for first input. But for next input it goes 0.088. Also it will be difficult to delete single number. — Apoorv Mote, Jan 10 '16 at 09:49
Formatter style is not the problem. First I divided 8 by 100 then I get 0.08. Then I divide 0.088 by 100 then I get 0.0088. After that numbers go haywire. — Apoorv Mote, Jan 10 '16 at 11:25
Of course you have to keep the cents (8) then divide 88 by 100 — vadian, Jan 10 '16 at 11:27

score 1 · Accepted Answer · answered Jan 10 '16 at 10:07

You could do something like having an index for actual decimal position, increment this index when user types a number, and decrement it when he deletes something. Then every time he enters or delete something according to the input and each time the input changes, reload it to set you formatted string.

override func viewDidLoad()
{
    super.viewDidLoad()

    self.index = 0
    self.oldValue = ""
    self.newValue = ""
    self.textField.addTarget(self, action: textFieldDidChange, forControlEvents: UIControlEvents.ValueChanged)
}

func textFieldDidChange(textField: UITextField)
{
    self.newValue = textField.text
    if self.newValue.characters.count > self.oldValue.characters.count
    {
        self.index++
    }
    else
    {
        self.index--
    }
    textField.text = //Formated string according to index
    self.oldValue = self.newValue
}

Good try but character count for 0.02, 0.24 & 2.29 remains same (3). So I cannot use your answer. — Apoorv Mote, Jan 10 '16 at 11:19
If you have 0.02 and the user types 4 in the textfield, you will have 0.024 and `"0.02".characters.count < "0.024".characters.count` — Aeradriel, Jan 10 '16 at 11:27

moving decimal point as I enter the input to textfield in swift

1 Answers1