NSNumberFormatter grouping - ios

Question

I would like to format string with numbers to look like this: XX XX XX (e.g. 12 34 56)
I'm using NSNumberFormatter with grouping separator:
let formatter = NSNumberFormatter()
formatter.usesGroupingSeparator = true
formatter.groupingSize = 2
formatter.groupingSeparator = " "
if let number = Int(theText.stringByReplacingOccurrencesOfString(" ", withString: "")) {
let numberToFormat = NSNumber(integer:number)
textField.text = formatter.stringFromNumber(numberToFormat)
}
This will work fine, if you enter number 123456 - it is formatted to 12 34 56
I use this inside shouldChangeCharactersInRange method so it should format number as you type. Grouping separator defines numbers are grouped by groupingSize value from right side, so when you type in 123456 this is how text changes:
1
12
1 23
12 34
1 23 45
12 34 45
and I would like to format it as following:
1
12
12 3
12 34
12 34 5
12 34 56
Is it possible to define from which side grouping separator groups numbers?

Answer 1

Not sure if you have to covert to Int, how about add a "0" at the end? Then remove the last "0".
let formatter = NSNumberFormatter()
formatter.usesGroupingSeparator = true
formatter.groupingSize = 2
formatter.groupingSeparator = " "
var str = "12345"
if str.characters.count % 2 != 0 {
str += "0"
}
if let number = Int(str.stringByReplacingOccurrencesOfString(" ", withString: "")) {
let numberToFormat = NSNumber(integer:number)
formatter.stringFromNumber(numberToFormat)
}
Another solution:
let string = "12345"
var results = [String]()
for index in 0 ..< string.characters.count-1 {
if index % 2 == 0 {
let range = NSRange(location: index, length: 2)
results.append((string as NSString).substringWithRange(range))
}
}
if string.characters.count % 2 != 0 {
let last = (string as NSString).substringFromIndex(string.characters.count-1)
results.append(last)
}

Answer 2

Swit 4
You have to use the delegate of UITextField : func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String)
this works fine :
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
if textField == YourTextField {
if (textField.text?.count)! < 8 {
let formatter = NumberFormatter()
formatter.usesGroupingSeparator = true
formatter.locale = NSLocale(localeIdentifier: "en_GB") as Locale?
formatter.groupingSize = 2
formatter.groupingSeparator = "-" // if you want the format XX-XX-XX
// Uses the grouping separator corresponding
if let groupingSeparator = formatter.groupingSeparator {
if string == groupingSeparator {
return true
}
if let textWithoutGroupingSeparator = textField.text?.replacingOccurrences(of: groupingSeparator, with: "") {
var totalTextWithoutGroupingSeparators = textWithoutGroupingSeparator + string
if string == "" { // pressed Backspace key
totalTextWithoutGroupingSeparators.characters.removeLast()
}
if let numberWithoutGroupingSeparator = formatter.number(from: totalTextWithoutGroupingSeparators),
let formattedText = formatter.string(from: numberWithoutGroupingSeparator) {
print(numberWithoutGroupingSeparator)
numberWithoutGroupingSeparators = String(format: "%#", numberWithoutGroupingSeparator)
textField.text = formattedText
return false
}
}
}
return true
}
}
return true
}