enable NSButton if NSTextfield is not empty - swift

Question

I am creating a OSX app and would like to enable a button when all textfield are filled. But do not have much experience with osx app as there seem to be some difference from ios.
This is what I have tried.
override func viewDidLoad() {
super.viewDidLoad()
btnCalculate.enabled = false
}
override func controlTextDidChange(obj: NSNotification) {
if panelsWideTextField.stringValue.isEmpty {
btnCalculate.enabled = false
} else {
btnCalculate.enabled = true
}
}
Hope someone has a good tip for me :-)
EDIT:
Complete code.
import Cocoa
//import AppKit
class ViewController: NSViewController, NSTextFieldDelegate {
#IBOutlet weak var panelHightTextField: NSTextField!
#IBOutlet weak var panelWidthTextField: NSTextField!
#IBOutlet weak var panelPitchTextField: NSTextField!
#IBOutlet weak var panelsHighTextField: NSTextField!
#IBOutlet weak var panelsWideTextField: NSTextField!
#IBOutlet weak var resWidthLabel: NSTextField!
#IBOutlet weak var resHightLabel: NSTextField!
#IBOutlet weak var lblScreenWidth: NSTextField!
#IBOutlet weak var lblScreenHight: NSTextField!
#IBOutlet weak var lblScreenArea: NSTextField!
#IBOutlet weak var btnCalculate: NSButton!
#IBOutlet weak var lblAmountPanels: NSTextField!
var panelHight = ""
var panelWidth = ""
var panelPitch = ""
var panelsHigh = ""
var panelsWidth = ""
var resWidth : Float = 0
var resHigh : Float = 0
var screenHight : Float = 0
var screenWidth : Float = 0
var screenArea : Float = 0
var ammountPanels : Float = 0
override func viewDidLoad() {
super.viewDidLoad()
btnCalculate.enabled = false
}
override func controlTextDidChange(obj: NSNotification) {
if panelsWideTextField.stringValue.isEmpty {
btnCalculate.enabled = true
} else {
btnCalculate.enabled = false
}
}
override var representedObject: AnyObject? {
didSet {
// Update the view, if already loaded.
}
}
#IBAction func calculateResButton(sender: AnyObject) {
takeUserData()
calculatehight()
calculatewidth()
calculateArea()
calculateAmountPanels()
}
func takeUserData(){
panelHight = panelHightTextField.stringValue
panelWidth = panelWidthTextField.stringValue
panelPitch = panelPitchTextField.stringValue
panelsHigh = panelsHighTextField.stringValue
panelsWidth = panelsWideTextField.stringValue
}
// Calculating resolution and physical hight
func calculatehight(){
let fpanelHight = Float(panelHight)
let fpanelPitch = Float(panelPitch)
let fpanelsHigh = Float(panelsHigh)
resHigh = fpanelHight! * fpanelsHigh! / fpanelPitch!
screenHight = fpanelHight! * fpanelsHigh! / 1_000
printText()
}
// Calculating resolution and physical width
func calculatewidth(){
let fpanelWidth = Float(panelWidth)
let fpanelPitch = Float(panelPitch)
let fpanelsWidth = Float(panelsWidth)
resWidth = fpanelWidth!*fpanelsWidth!/fpanelPitch!
screenWidth = fpanelWidth!*fpanelsWidth! / 1_000
printText()
}
// Calculating sqm of LED screen
func calculateArea(){
let fpanelHight = Float(panelHight)
let fpanelsHigh = Float(panelsHigh)
let fpanelWidth = Float(panelWidth)
let fpanelsWidth = Float(panelsWidth)
screenArea = (fpanelHight! * fpanelsHigh!) * (fpanelWidth! * fpanelsWidth!) / 1_000_000
printText()
}
// Calculating the amount of panels used.
func calculateAmountPanels(){
let fpanelsHigh = Float(panelsHigh)
let fpanelsWidth = Float(panelsWidth)
ammountPanels = (fpanelsWidth! * fpanelsHigh!)
printText()
}
// Outputting text to labels with correct format.
func printText(){
let formatResHigh = String(format: "%0.0f", resHigh)
let formatResWidth = String(format: "%0.0f", resWidth)
let formatScreenHight = String(format: "%0.2f", screenHight)
let formatScreenWidth = String(format: "%0.2f", screenWidth)
let formatScreenArea = String(format: "%0.0f", screenArea)
let formatAmmountPanels = String(format: "%0.0f", ammountPanels)
resHightLabel.stringValue = "\(formatResHigh)px"
resWidthLabel.stringValue = "\(formatResWidth)px"
lblScreenHight.stringValue = "\(formatScreenHight)m"
lblScreenWidth.stringValue = "\(formatScreenWidth)m"
lblScreenArea.stringValue = "\(formatScreenArea) sqm"
lblAmountPanels.stringValue = "\(formatAmmountPanels)"
}
}

Answer 1

I had the same problem but I found simple solution: checkbox can enable and disable NSButton.
import Cocoa
class ViewController: NSViewController {
#IBOutlet weak var btnCalculate: NSButton!
#IBOutlet weak var checkBox: NSButton!
override func viewDidLoad() {
super.viewDidLoad()
btnCalculate.enabled = false
checkBox.state = 0
}
#IBAction func checkAgree(sender: NSButton) {
if btnCalculate.stringValue.characters.count > 0 && checkBox.state == 1 {
btnCalculate.enabled = true
} else {
btnCalculate.enabled = false
}
}
}