CODEWITHSUNDEEP
iosxcodeswiftuicollectionviewreloaddata
noanoanoa
noanoanoa

Reputation: 41

UICollectionViewCells not showing after reloadData()

I want to make an infinite scroll collection view, so in this code I add 10 to the number of cells every time the index path is equals to the last cell item, and then reload the data in the collection. The function works; I can scroll infinitely, but if I stop, and then scroll a little up or down, everything is blank. The cells aren't showing.

My theory is that it has something to do with dequeueReusableCellWithReuseIdentifier, and it decides to only show the cells that are currently on the screen.

View when scrolling (I added the numbers to the cells outside of Xcode)

View with the missing cells above when scrolling a bit after stopping

private let reuseIdentifier = "Cell"
private var numberOfCells = 20

class CollectionViewController: UICollectionViewController {
    override func viewDidLoad() {
        super.viewDidLoad()

    }

    override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier(reuseIdentifier, forIndexPath: indexPath)

        if indexPath.row == numberOfCells - 1 {
            numberOfCells += 10
            self.collectionView?.reloadData() 
        }

        cell.contentView.backgroundColor = UIColor.blueColor()
        return cell
    }

    override func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
        return 1
    }

    override func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return numberOfCells
    } 
}

Upvotes: 2

Views: 1550

Answers (4)

Elshad Karimov
Elshad Karimov

Reputation: 322

Swift 4.2

reload it like this.

DispatchQueue.main.async(execute: collectionView.reloadData)

Upvotes: 0

gerram
gerram

Reputation: 520

var numberOfCells: Int = 20 {    
    didSet {
        if numberOfCells != oldValue  {
            self.collectionView?.reloadData()
        }
    }
}

Upvotes: 1

Hardik
Hardik

Reputation: 139

I am doing similar things in Table View and it is working for me. The only difference is that if indexPath.row is last cell then I am calling another function which do some stuff (required for me) and calling reloadData() into that function only. Try this way, I am not sure, but it may solve your problem.

Upvotes: 0

Alexander Doloz
Alexander Doloz

Reputation: 4198

Calling reloadData from cellForItemAtIndexPath is bad. Use other delegate method for that, for example, scrollViewDidScroll.

Upvotes: 2

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