CODEWITHSUNDEEP
iosswiftuicollectionviewuicollectionviewcell
marco
marco

Reputation: 676

Persistent Collection View Cell Selection

please bear with me as I am new to swift programming.

I have a myCollectionViewController that is a subclass of UICollectionViewController. The cells for the MyCollectionViewController are a class of MyCollectionViewCell, which is a custom UICollectionViewCell.

What I am trying to do is change the background of the MyCollectionViewCell based on the user selection AND have this selection persist when the user scrolls to other cells of the MyCollectionViewController. I have tried two ways to do this, and so far both have failed.

The first way was to write code in the didSelectItemAt method of the MyCollectionViewController: 

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "myCell", for: indexPath) as! MyCollectionViewCell

    cell.contentView.backgroundColor = UIColor.red
}

However, this did not work and the cell colour was not changed.

The other way I tried to do this was by changing the isSelected property of the MyCollectionViewCell.

override var isSelected: Bool {
    // Change what happens when the user selects a cell

    didSet {

        if self.isSelected {
            self.contentView.backgroundColor = Colours.primary

        } else {
            self.contentView.backgroundColor = Colours.secondary

        }  
    }
}

Although this worked, the selection did not persist. That is when the user scrolled to a different cell in the collectionView and then scrolled back, the selection was gone.

Any advice would be appreciated.

Upvotes: 1

Views: 449

Answers (1)

Shehata Gamal
Shehata Gamal

Reputation: 100533

Don't use dequeue in didSelectItemAt as it'll return other cell than the clicked 

var allInde = [IndexPath]()

  func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {

    let cell = collectionView.cellForItem(at:indexPath) as!   MyCollectionViewCell

    cell.contentView.backgroundColor = UIColor.red

    if !(allIndex.contains(indexPath)) {
        allInde.append(indexPath)
    }
}

and in cellForItem check whether indexpath to show is in the array and color it 

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "id", for: indexPath as IndexPath) as! MyCollectionViewCell

       if allIndex.contains(indexPath) {
          cell.contentView.backgroundColor = Colours.primary
       }
       else {
          cell.contentView.backgroundColor = Colours.secondary
       }
  }

// se here updated code

SPRAIN

Upvotes: 2

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