Swift: NSTextField numberStyle not calling action

Question

I have a NSTextField that I have setup with the following code:

func tableView(tableView: NSTableView, viewForTableColumn tableColumn: NSTableColumn?, row: Int) -> NSView?
{

    let cell : NSTableCellView? = tableView.makeViewWithIdentifier("AutomaticTableColumnIdentifier.0", owner: self) as! NSTableCellView?

    cell!.textField!.floatValue = 4.55
    let numberFormatter = NSNumberFormatter()
    numberFormatter.numberStyle = .CurrencyStyle
    numberFormatter.maximumFractionDigits = 0
    cell!.textField! = numberFormatter

    return cell
}

I have also set up an action set up for when the field is modified in the NSTextFieldDelegate.

@IBAction func saveCell(sender: AnyObject)
{
    print("saveCell")
}

My problem is that the saveCell action is only triggered when I type in a value that exactly matches the currency style. i.e. typing £45 is OK but nothing happens when I enter a plain 45.

If I remove the NSNumberFormatter then it will accept any entry, but doesn't format the textField in the way that I want it.

How can I accept the 45 value without the currency symbol? What's the best way of doing this?

Answer 1

You can subclass your NSTextField as follow:

import Cocoa

class CurrencyField: NSTextField {

    var percent: Double {
        return Double(Int(numbers) ?? 0) / 100
    }

    var currency: String {
        return Number.currency.string(from: percent.number) ?? ""
    }

    var numbers: String {
        return stringValue.components(separatedBy: CharacterSet(charactersIn: "0123456789").inverted).joined()
    }

    override func awakeFromNib() {
        super.awakeFromNib()
        alignment = .right
        stringValue = currency

    }

    override func textDidChange(_ notification: Notification) {
        Swift.print("--> textDidChange")
        stringValue = currency
    }

    override func draw(_ dirtyRect: NSRect) {
        super.draw(dirtyRect)
        // Drawing code here.
    }
}

---

extension NumberFormatter {
    convenience init(numberStyle: NumberFormatter.Style) {
        self.init()
        self.numberStyle = numberStyle
    }
}

---

struct Number {
    static let currency = NumberFormatter(numberStyle: .currency)
}

---

extension Double {
    var number: NSNumber {
        return NSNumber(value: self)
    }
}

---

Edit/Update:

If you need an Integer Field you can do as Follow:

import Cocoa

class IntegerField: NSTextField {

    var value: Int { return Int(numbers) ?? 0 }

    var currency: String { return Number.currency.string(from: value.number) ?? "" }

    var numbers: String { return stringValue.components(separatedBy: CharacterSet(charactersIn: "0123456789").inverted).joined() }

    override func awakeFromNib() {
        super.awakeFromNib()
        alignment = .right
        stringValue = currency
    }
    override func textDidChange(_ notification: Notification) {
        Swift.print("--> textDidChange")
        stringValue = currency
    }
    override func draw(_ dirtyRect: NSRect) {
        super.draw(dirtyRect)
        // Drawing code here.
    }
}

extension NumberFormatter {
    convenience init(numberStyle: NumberFormatter.Style, maximumFractionDigits: Int = 0) {
        self.init()
        self.numberStyle = numberStyle
        self.maximumFractionDigits = maximumFractionDigits

    }
}

struct Number {
    static let currency = NumberFormatter(numberStyle: .currency)
}

extension Int {
    var number: NSNumber {
        return NSNumber(value: self)
    }
}