Can't deselect item in collectionView

Question

i have collectionView. At the first launch I change color for first item to black. The problem is that when I select another item I want it to become black and first item become white. I use didSelectItemAtIndexPath and didDeselectItemAtIndexPath, but if i don't click the first item then I can't change it's color when I click another one. Can someone help me?

Answer 1

set a selectedindexpath and reload collection view according to selected index path.

class CollectionViewController: UICollectionViewController {

var selectedIndexPath : IndexPath?

override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "identifier", for: indexPath)
    if indexPath == selectedIndexPath {
        cell.backgroundColor = UIColor.black
    } else {
        cell.backgroundColor = UIColor.white
    }
    return cell
}

override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    selectedIndexPath = indexPath
    collectionView.reloadData()
}

}

Answer 2

You can do it by following way.

Override the method in UICollectionViewCell Class like below

override var isSelected: Bool{
    didSet{
        if(self.isSelected){
            yourView.backgroundColor = YourSelectedColor

        }else{
            yourView.backgroundColor = YourUnSelectedColor
        }
    }
}

No Need to do anything in didSelectItemAt or didDeSelectItemAt methods.

Answer 3

Your element from your data source array should somehow know about current state of cell. For example you can have property of your custom object:

var isSelected: Bool = false

in didSelectItemAt method first change every element's isSelected property to false and then for selected element set true and then reload data of collectionView

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    dataSourceArray.forEach { $0.isSelected = false }
    dataSourceArray[indexPath.row] = true
    collectionView.reloadData()
}

then in cellForRowAt change backgroundColor of cell depends on isSelected property of certain element in your data source array

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    ...
    cell.backgroundColor = dataSourceArray[indexPath.row] ? .black : .white
    ...
}

---

var selectedIndexPath = IndexPath?

Alternatively you can just save indexPath of selected cell as global variable

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    selectedIndexPath = indexPath
    collectionView.reloadData()
}

and then in cellForRowAt you can set backgroundColor of cell depends on condition if indexPath is equal to selectedIndexPath

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    ...
    cell.backgroundColor = indexPath == selectedIndexPath ? .black : .white
    ...
}