CODEWITHSUNDEEP
iosswiftuicollectionviewcellcollectionview
Asbis
Asbis

Reputation: 532

swift - Call a function between collectionview cell class and collectionview Controller

Hi i have been struggle with this probleme for some time and cant figure it out.

What i would like to do is, press a button inside a collectionview cell, and perform a transition to next cell.

This is the function i want to call that is inside the the collectionview controller class:

func done(){
    let scrollIndex: NSIndexPath = NSIndexPath(item: 1, section: 0)// NSIndexPath(forItem: 0, inSection: 0)
    CollectionViewet.scrollToItem(at: scrollIndex as IndexPath, at: .centeredHorizontally, animated: true)
}

What happens is that when i call a function from collectionview controller, it give me this

Unexpectedly found nil while unwrapping an Optional value

What i am doing wrong?

Upvotes: 1

Views: 650

Answers (1)

zombie
zombie

Reputation: 5259

The UICollectionViewController has a subview by default called collectionView which you should use to scroll to an item

So if you override the data source delegate methods properly you should be able to scroll as follows

func done() {

    let numberOfRows = collectionView?.numberOfItems(inSection: 0) ?? 0

    guard numberOfRows > 1 else { return }

    let indexPath = IndexPath(row: 1, section: 0)

    collectionView?.scrollToItem(at: indexPath, at: .centeredHorizontally, animated: true)
}

I added the guard line to prevent the app from crashing in case of an empty data for some reason.

Upvotes: 1

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