Detect visible cell inside CollectionView and call function

Question

Created Jan ’17

Replies 2

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Views 5.3k

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Hi,

I'm trying to get the current visible cell from my collectionview and call a function based upon the indexPath row value.

I tried to use willDisplayCell but when I added an if else conditional it fired when the cells weren't visible. I also tried

indexPathsForVisibleItems but this too failed to work.

The functionality should be when the cell index is 0 run one method else run another.

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
     
        if collectionView == self.locationsCollectionView {
         
            let cell = locationsCollectionView.dequeueReusableCell(withReuseIdentifier: "storedLocationCell", for: indexPath) as! StoredLocationsCell
         

            let storedLocation = storedLocationsData[indexPath.row]
         
            
            cell.locationCity.text = storedLocation.name?.uppercased()
            cell.locationRegion.text = storedLocation.region?.uppercased()
            for label in cell.labelSpacing {
                label.addTextSpacing(1)
            }
            cell.locationRegion.textColor = lightGreyColor
         
            return cell
         
        }
}

Thanks!

Answered by JayCo in 208881022

I managed to find the solution, turns out another method was calling reloadData, creating an infinite loop. Hope it helps anyone.

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Answer 1

JayCo OP

Jan ’17

I've managed to find some sort of way but the getAnotherLocation() is firing multiple times inside willDisplayCell.

func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
        if collectionView == self.locationsCollectionView {
            let storedLocation = storedLocationsData[indexPath.row]
           
            if indexPath.row != 0 {
                print(storedLocation.name!)
                getAnotherLocation(lat: storedLocation.latitude, lon: storedLocation.longitude, spinner: true)
            }
            if indexPath.row == 0 {
                print(storedLocation.name!)
            }
           
        } else {
           
        }
    }

I don't understand why it's firing multiple times. Is there a refresh method that keeps calling on willDisplay Cell?

0

Answer 2

JayCo OP

Jan ’17

Accepted Answer

I managed to find the solution, turns out another method was calling reloadData, creating an infinite loop. Hope it helps anyone.

0