Numbers not parsed on Devices with Hungarian locale

[gezamiklo]

The decimal sign is different. That is why it fails to parse the number. Should used a NOT localized version of numberformatter in the calculator

[gezamiklo]

Here's a possible solution:
The "." string (which is the decimal separator in Double values) has to be replaced with the decimal deparator belonging to current locale: NSNumberFormatter().decimalSeparator -> String?

// MARK: Computed variables
var displayValue: Double? {
get {
var textValue = "0"
if let text = digitsLabel.text {
textValue = text.stringByReplacingOccurrencesOfString(".", withString: NSNumberFormatter().decimalSeparator!, options: NSStringCompareOptions.LiteralSearch, range: nil);
}
println(textValue)
if let dValue = NSNumberFormatter().numberFromString(textValue)?.doubleValue {
return dValue
} else {
return nil
}
}
set {
if newValue == nil {
digitsLabel.text = ""
} else {
digitsLabel.text = "(newValue!)"
}
}
}

[gezamiklo]

Note that you can extract this as a property (?? is Nil-coalescing operator):
let decimalSeparator = NSNumberFormatter().decimalSeparator ?? "."
...
var displayValue: Double? {
...
if let text = digitsLabel.text {
textValue = text.stringByReplacingOccurrencesOfString(".", withString: decimalSeparator, options: NSStringCompareOptions.LiteralSearch, range: nil);
}
...
}