CODEWITHSUNDEEP
iosswiftuicollectionview
user9911101
user9911101

Reputation:

CollectionView scrolling changes the selected cells

CollectionView scrolling changes the selected cells. For example, there are 26 letters in my collectionView, items[0] is A, items[1] is B, ... items[25] is Z, now I selected items[1], it is B, and when I scroll the collectionView, items[1] will become deselected and there is another item will be selected. I know the problem is caused by Reuse but I don't know how to fix it properly even I use some solution that showed in google or StackOverflow.

My viewDidLoad:

collectionView.allowsMultipleSelection = false

My CollectionViewCell Class:

import UIKit
class AddCollectionViewCell: UICollectionViewCell {
}

My CollectionView Setting:

func numberOfSections(in collectionView: UICollectionView) -> Int {
        return 1
    }
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return iconSet.count
    }
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "iconCell", for: indexPath) as! IconCollectionViewCell
        cell.iconImage.image = UIImage(named:iconSet[indexPath.row])
        return cell

    }

My CollectionView's didSelecteItemAt function:

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

        if let cell = collectionView.cellForItem(at: indexPath) {
            cell.backgroundColor = UIColor(red: 255/255, green: 255/255, blue: 255/255, alpha: 0.3)
            cell.backgroundView?.layer.cornerRadius = 5
        }

My CollectionView's didDeSelecteItemAt function:

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

        if let cell = collectionView.cellForItem(at: indexPath) {
            cell.backgroundColor = UIColor(red: 255/255, green: 255/255, blue: 255/255, alpha: 0.0)
            cell.backgroundView?.layer.cornerRadius = 5
        }
    }

Upvotes: 0

Views: 2309

Answers (2)

Dhaval Dobariya
Dhaval Dobariya

Reputation: 473

You can achieve this by either store all selected item's index in separate array or you can manage separate property like isSelected in dictionary or array of custom class's objects whichever you used to fill your collectionview cells.

You can simply use array like below: var arrIndex : [Int] = Int

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "iconCell", for: indexPath) as! IconCollectionViewCell
        cell.iconImage.image = UIImage(named:iconSet[indexPath.row])

         if arrIndex.contains(indexPath.item) {
               cell.backgroundColor = UIColor(red: 255/255, green: 255/255, blue: 255/255, alpha: 0.3)

          }
          else {
                cell.backgroundColor = UIColor(red: 255/255, green: 255/255, blue: 255/255, alpha: 0.0)

          }
        return cell

    }

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

     if !arrIndex.contains(indexPath.item) {
        arrIndex.append(indexPath.item)
        collectionview.reloadData()

     }
 }

func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) {
       if arrIndex.contains(indexPath.item) {
            arrIndex = arrIndex.filter { $0 != indexPath.item }
            collectionview.reloadData()
         }
    }

Upvotes: 1

Shehata Gamal
Shehata Gamal

Reputation: 100503

You can try

 var selectedIndex = 0  // set default or nil and check it's nullability before usage

//

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "iconCell", for: indexPath) as! IconCollectionViewCell
        cell.iconImage.image = UIImage(named:iconSet[indexPath.row])

         if indexPath.row == selectedIndex {
               cell.backgroundColor = UIColor(red: 255/255, green: 255/255, blue: 255/255, alpha: 0.3)

          }
          else {
                cell.backgroundColor = UIColor(red: 255/255, green: 255/255, blue: 255/255, alpha: 0.0)

          }
        return cell

    }

My CollectionView's didSelecteItemAt function:

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

      selectedIndex = indexPath.row
      collectionview.reloadData()
 }

My CollectionView's didDeSelecteItemAt function:

func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) {
       // remove this
    }

Upvotes: 0

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