On Change Function In Class Swift - swift

Question

I created a DropDownMenu class, but I need to know when the value changed in the ViewController. Like a UIScrollView didScroll, but for the value change in my class.
func scrollViewDidScroll(_ scrollView: UIScrollView)
I need something like that, but for the class!
Here is the class...
class DropDownMenu: UIStackView {
var options: [String]! = [] // Labels for all of the options
var titleButton: UIButton! = UIButton() // The Main Title Button
var target: UIViewController! // The target to get the main view. Maybe remove and automatically do it later
var textColor: UIColor! = UIColor.black // The Color of the text of the options
var bgColor: UIColor! = UIColor.clear
var borderWidth: CGFloat! = 0.0
var borderColor: CGColor! = UIColor.black.cgColor
var uiBorderColor: UIColor? = nil
var cornerRadius: CGFloat! = 0.0
var font: UIFont! = UIFont.systemFont(ofSize: 18)
var images: [UIImage]? = nil
var imageInsets: [UIEdgeInsets]? = nil
var imageInset: UIEdgeInsets? = nil
var value: String! {
get {
return currentSelected
}
set {
currentSelected = newValue
}
}
private var currentSelected: String! = ""
init(options: [String]) {
self.options = options
super.init(frame: CGRect.zero)
self.translatesAutoresizingMaskIntoConstraints = false
self.axis = .vertical
}
init(titleButton: UIButton) {
self.titleButton = titleButton
super.init(frame: CGRect.zero)
self.translatesAutoresizingMaskIntoConstraints = false
self.axis = .vertical
}
func createDropDownMenu() {
currentSelected = titleButton.titleLabel?.text
let mainFrame = titleButton.frame
print("Frame: \(mainFrame)")
print("StackView frame: \(self.frame), axis: \(self.axis)")
if uiBorderColor != nil {
borderColor = uiBorderColor!.cgColor
}
self.widthAnchor.constraint(equalToConstant: mainFrame.width).isActive = true
self.leftAnchor.constraint(equalTo: titleButton.leftAnchor).isActive = true
self.topAnchor.constraint(equalTo: titleButton.bottomAnchor, constant: self.spacing).isActive = true
var y: CGFloat = 0
var place = 0
for title in self.options {
let button = UIButton(frame: CGRect(x: 0, y: y, width: mainFrame.width, height: mainFrame.height))
button.setTitle(title, for: .normal)
button.setTitleColor(textColor, for: .normal)
button.backgroundColor = bgColor
button.addTarget(self, action: #selector(dropDownOptionClicked(_:)), for: .touchUpInside)
button.layer.cornerRadius = cornerRadius
button.layer.borderWidth = borderWidth
button.layer.borderColor = borderColor
button.titleLabel?.font = font
if images != nil {
button.setBackgroundImage(images![place], for: .normal)
if imageInsets != nil {
button.imageEdgeInsets = imageInsets![place]
} else if imageInsets == nil && imageInset != nil{
button.imageEdgeInsets = imageInset!
} else {
button.imageEdgeInsets = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
}
}
print("Button: \(button), Title: \(String(describing: button.titleLabel?.text)), Target: \(button.allTargets)")
button.isHidden = true
button.alpha = 0
self.addArrangedSubview(button)
button.translatesAutoresizingMaskIntoConstraints = false
button.widthAnchor.constraint(equalToConstant: mainFrame.width).isActive = true
button.heightAnchor.constraint(equalToConstant: mainFrame.height).isActive = true
print("Subviews: \(self.arrangedSubviews)")
y += mainFrame.height
place += 1
print("y: \(y)")
}
}
#objc func openDropDown(_ sender: UIButton) {
print("Open DropDownMenu")
self.arrangedSubviews.forEach { (button) in
UIView.animate(withDuration: 0.7) {
button.isHidden = !button.isHidden
button.alpha = button.alpha == 0 ? 1 : 0
self.target.view.layoutIfNeeded()
}
}
}
#objc private func dropDownOptionClicked(_ sender: UIButton) {
let text = sender.titleLabel?.text
print(text as Any)
currentSelected = text
print("Value: \(String(describing: value))")
titleButton.setTitle(text, for: .normal)
openDropDown(sender)
}
init() {
super.init(frame: CGRect.zero)
self.translatesAutoresizingMaskIntoConstraints = false
self.axis = .vertical
}
required init(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
Here is the creation in ViewController...
let titleButton = UIButton(frame: CGRect(x: 50, y: 290, width: 100, height: 40))
titleButton.backgroundColor = UIColor.white
titleButton.setTitle("Grade", for: .normal)
titleButton.setTitleColor(UIColor.black, for: .normal)
titleButton.layer.borderWidth = 2
titleButton.layer.cornerRadius = 10
let dp = DropDownMenu(options: ["1", "Freshman", "Sophomore", "Junior", "Senior", "College"])
dp.titleButton = titleButton
dp.target = self
dp.borderWidth = 2
dp.spacing = 5
dp.cornerRadius = 10
dp.bgColor = UIColor.white
titleButton.addTarget(dp, action: #selector(dp.openDropDown(_:)), for: .touchUpInside)
infoBox.addSubview(titleButton)
infoBox.addSubview(dp)
dp.createDropDownMenu()
The class works as expected.
I really need help on this. No answer is a bad one. This is all of my code.

Answer 1

You usually do that with a delegate:
class DropDownMenu: UIStackView {
weak var delegate: DropDownMenuDelegate?
var value: String! {
get {
return currentSelected
}
set {
if currentSelected != newValue {
currentSelected = newValue
self.delegate?.valueDidChange(self)
}
}
}
}
protocol DropDownMenuDelegate: class {
func valueDidChange(_ menu: DropDownMenu)
}
Then in your View Controller:
let dp = DropDownMenu(options: ["1", "Freshman", "Sophomore", "Junior", "Senior", "College"])
dp.delegate = self
(typing this in the blind as I'm away from Xcode so there may be syntax errors)