Digit input in a text field - swift

Question

Additional question:
Still need some help with my code. The textfield is 'measuredValue' and I plan to have 30 different texfields (measuredValue1...30). When I type '923' the text will be set to '9.23' right away. Then I want to add '4'... for '92.34' but that doesn't work. Thanks for helping out.
func textField(textField: UITextField,
shouldChangeCharactersInRange range: NSRange,
replacementString string: String)
-> Bool {
if count(string) == 0 { return true }
var measuredValue = (textField.text as NSString).stringByReplacingCharactersInRange(range, withString: string)
switch textField {
case digitsOnlyTextField:
if count(measuredValue) == 3 || count(measuredValue) == 4 {
let stringNumeric = Double(measuredValue.toInt()!) / 100
measuredValue = String(format:"%.2f", stringNumeric)
digitsOnlyTextField.text = measuredValue
}
return measuredValue.containsOnlyCharactersIn("0123456789") && count(measuredValue) <= 4
default:
return true
}
}
Original question:
I would like to validate my text fields to get the right input for my app. Input needs to be formatted like '9.90' or '15.34'. So always 3 or 4 digits, and always 2 decimals.
I would like to use 'numberpad keyboard' (just 0...9, no point) and add the decimal point after the user exits the field. So the user input is 990 or 1534, and then in the text field it will become 9.90 or 15.34 automatically.
I tried searching for examples first, but didn't find what I was looking for.
Any help appreciated.
Jan

Answer 1

You have to implement the UITextField delegate method
func textFieldDidEndEditing(textField: UITextField) {
//Logic goes here....
var textString = textField.text as! String
let textLength = countElements(textString)
if textLength >= 3 && textLength <= 4 {
let stringNumeric = Double(textString.toInt()!) / 100
let texts = String(format:"%.2f", stringNumeric)
textField.text = texts
}
}
Your class should confirm to the protocol UITextFieldDelegate

Answer 2

this is the 'final' code I used (but I'm open for improvements!). A few remarks:
when a user clicks the background (and leaves the textfield) the
decimal point gets set.
when a user copies & pastes text from another app, this code handles that.
when a user goes back in the textfield for editing, the decimal point gets set again.
Deleting a value (to an empty textfield) is handled correctly.
So I'm pleased. Thanks for the help.
import UIKit
class ViewController: UIViewController, UITextFieldDelegate {
#IBOutlet weak var numberField: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
numberField.delegate = self
numberField.keyboardType = UIKeyboardType.NumberPad
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
// Tap background to add decimal point and defocus keyboard
#IBAction func userTappedBackground(sender: AnyObject) {
for view in self.view.subviews as! [UIView] {
if let textField = view as? UITextField {
if count(numberField.text) > 0 {
var numberString = numberField.text
numberString = numberString.stringByReplacingOccurrencesOfString(".", withString: "", options: NSStringCompareOptions.LiteralSearch, range: nil)
var numberFromString = Double(numberString.toInt()!) / 100
numberField.text = String(format:"%.2f", numberFromString)
}
textField.resignFirstResponder()
}
}
}
func textField(textField: UITextField,
shouldChangeCharactersInRange range: NSRange,
replacementString string: String)
-> Bool {
var result = true
var prospectiveText = (textField.text as NSString).stringByReplacingCharactersInRange(range, withString: string)
prospectiveText = prospectiveText.stringByReplacingOccurrencesOfString(".", withString: "", options: NSStringCompareOptions.LiteralSearch, range: nil)
if textField == numberField {
if count(string)>0 {
let disallowedCharacterSet = NSCharacterSet(charactersInString: "0123456789").invertedSet
let replacementStringIsLegal = string.rangeOfCharacterFromSet(disallowedCharacterSet) == nil
let resultingStringLengthIsLegal = count(prospectiveText) <= 4
let scanner = NSScanner(string: prospectiveText)
let resultingTextIsNumeric = scanner.scanDecimal(nil) && scanner.atEnd
result = replacementStringIsLegal && resultingStringLengthIsLegal && resultingTextIsNumeric
}
}
return result
}