Update UIButton's image according to Model - swift

Question

I have a UITableView where each cell get's its data from my model class, which is an array in my TableViewController class. The model for each cell is set in cellForRowAtIndexPath. My model has a "isFavorited" property. My custom cell class has a UIButton with an image of a star.
If model.isFavorited == false, the UIButton image is a gray star.
If model.sFavorited == true, the UIButton image should change to a yellow star.
So far, I have tried to approach this like so:
private let normal = UIImage(named: "star")
private let selection = UIImage(named: "star highlighted")
class CustomCell: UITableViewCell {
var model: Model? {
didSet{
favoriteButton.selected = (model?.isFavorite)!
}
}
#IBOutlet var favoriteButton: UIButton!
override func awakeFromNib() {
super.awakeFromNib()
favoriteButton.adjustsImageWhenHighlighted = true
favoriteButton.setImage(normal, forState: .Normal)
favoriteButton.setImage(selection, forState: .Highlighted)
favoriteButton.setImage(selection, forState: .Selected)
}
#IBAction func favoriteTapped(sender: AnyObject) {
//UPDATE THE MODEL
model?.isFavorite = !(model?.isFavorite)!
}
}
This code successfully changes a star from gray to yellow and vice-versa thanks to didSet being called to update the favoriteButton.selected boolean with the value from (model?.isFavorite)!.
HOWEVER, as I scroll far enough through my tableview, and try to come back to the specific cell I favorited, the image will reappear as unfavorited (gray star instead of yellow star).
If my model is being updated when I tap the button, and the UIButton's image is adjusted during didSet as a result of this change, why does it revert back to the defaulted state when scrolling back to this cell??
EDIT:
My code in cellForRowAtIndexPath
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell: CustomCell = tableView.dequeueReusableCellWithIdentifier(reuseIdentifier, forIndexPath: indexPath) as! CustomCell
cell.model = modelArray[indexPath.row]
return cell
}

Answer 1

Basically you could subclass the UIButton with custom images set based on the tap. I had the same issue and solved it using below:
class FavioriteButton: UIButton {
//Images
let normalImage = UIImage(named: "star")! as UIImage
let selectedImage = UIImage(named: "star_highlighted")! as UIImage
//Bool property
var isSelected: Bool = false {
didSet {
if isSelected == true {
self.setImage(normalImage, forState: .Normal)
}else{
self.setImage(selectedImage, forState: .Normal)
}
}
}
override func awakeFromNib() {
super.awakeFromNib()
self.addTarget(self, action: #selector(buttonClicked(_:)), forControlEvents: .TouchUpInside)
self.isSelected = false
}
func buttonClicked(sender: UIButton) {
if sender == self {
if isSelected == true {
isSelected = false
}else{
isSelected = true
}
}
}
}
Hope it helps you.