Trying to override "selected" in UICollectionViewCell Swift for custom selection state

Question

I am trying to implement a custom selection style for my cells in a UICollectionView. Even though it is easily possible to do this manually in the didSelect and didDeSelect methods I would like to achieve this by manipulating the "selected" variable in UICollectionViewCell.

I have this code for it:

    override var selected: Bool {
    get {
        return super.selected
    }
    set {
        if newValue {
            self.imageView.alpha = 0.5
            println("selected")
        } else if newValue == false {
            self.imageView.alpha = 1.0
            println("deselected")
        }
    }
}

Now, when I select a cell, the cell gets highlighted but "selected" gets printed twice and the deselection does not work (even though both UICollectionView methods are implemented).

How would I go about this? Thanks!

Have you tried putting a breakpoint and tracing when the first "selected" gets hit? — quantumpotato, Jul 09 '15 at 23:23
Thanks. Helped me solve the problem. super.selected was not being modified — Julius, Jul 09 '15 at 23:36

score 42 · Accepted Answer · answered Dec 07 '16 at 20:32

42

And for Swift 3.0:

override var isSelected: Bool {
    didSet {
        alpha = isSelected ? 0.5 : 1.0
    }
}

answered Dec 07 '16 at 20:32

Morten Gustafsson

1,869
2
24
34

This one should be selected as an answer because it corresponds to newest version of iOS and uses only `didSet`. – tomas789 Jan 09 '17 at 09:37
Why is isSelected called when scrolling? – Munib Jul 20 '18 at 13:43

score 31 · Answer 2 · answered Jul 09 '15 at 23:36

31

Figured it out by stepping into code. The problem was that the super.selected wasn't being modified. So I changed the code to this:

override var selected: Bool {
    get {
        return super.selected
    }
    set {
        if newValue {
            super.selected = true
            self.imageView.alpha = 0.5
            println("selected")
        } else if newValue == false {
            super.selected = false
            self.imageView.alpha = 1.0
            println("deselected")
        }
    }
}

Now it's working.

answered Jul 09 '15 at 23:36

Julius

1,451
1
15
19

1

Glad it's working! You should be able to mark your answer as correct soon – quantumpotato Jul 10 '15 at 01:27
great..!! helped that (Y) and thumbs up for answering own question – Pratik Jamariya Jan 07 '17 at 06:07
Maybe add an update to Swift 3. selected is no "isSelected" – JoakimE Apr 30 '17 at 13:08

score 14 · Answer 3 · answered Apr 19 '16 at 19:53

14

Try this one.

override var selected: Bool {
    didSet {
        self.alpha = self.selected ? 0.5 : 1.0
    }
}

answered Apr 19 '16 at 19:53

osrl

8,168
8
36
57

score 2 · Answer 4 · answered May 06 '22 at 04:08

For Swift 5, put this code in the cell

override var isSelected: Bool {
    get {
        return super.isSelected
    }
    set {
        if newValue {
            super.isSelected = true
            self.lbl_Sub_Category.textColor = UIColor.white
            self.ly_Container.backgroundColor = UIColor.black
            print("selected")
        } else if newValue == false {
            super.isSelected = false
            self.lbl_Sub_Category.textColor = UIColor.black
            self.ly_Container.backgroundColor = UIColor.white
            print("deselected")
        }
    }
}

You can select the first item of the collection view using this code in the viewcontroller:

    grid_SubCategories.reloadData()
    
    let firstItem:IndexPath = IndexPath(row: 0, section: 0)
    grid_SubCategories.selectItem(at: firstItem, animated: false, scrollPosition: .left)

Trying to override "selected" in UICollectionViewCell Swift for custom selection state

4 Answers4

Linked