一个tableView单元中有两个collectionViews。 collectionViews没有出现

Question

I have two different collectionViews inside one table view cell. Reason is because I am trying to find the best way to implement one horizontal collectionView and a vertical collecitonView that displays different data. I just want to get the horizontal collectionView to scroll down with the page when users are scrolling with the vertical collection view.

I have implemented some code to try to get both collectionViews working inside the table view, however the collection Views are not appearing.

class PeopleToFollowHeader: UITableViewCell, UICollectionViewDataSource, UICollectionViewDelegate {



    @IBOutlet weak var collectionViewA: UICollectionView!
    @IBOutlet weak var collectionViewB: UICollectionView!    



    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        if collectionView == self.collectionViewA {
            return 6
        } else {
            return posts.count
        }
    }

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

        if collectionView == self.collectionViewA {
            let cellA = collectionView.dequeueReusableCell(withReuseIdentifier: "FollowCell", for: indexPath) as! PeopleToFollowCollectionCell
            return cellA
        } else {
            if collectionView == self.collectionViewB {
            let cellB = collectionView.dequeueReusableCell(withReuseIdentifier: "FollowingFeed", for: indexPath) as! FollowingCell
            cellB.posts = posts[indexPath.item]
            return cellB
        }

            return UICollectionViewCell()
    }

    }


    override func awakeFromNib() {
        super.awakeFromNib()
        fetchPosts()
        // Display collectionViews
        collectionViewA.delegate = self
        collectionViewA.dataSource = self
        collectionViewB.delegate = self
        collectionViewB.dataSource = self
        self.addSubview(collectionViewA)
        self.addSubview(collectionViewB)
        collectionViewA.reloadData()
        collectionViewB.reloadData()


    }
    ```

Answer 1

You should reload your collection views after fetchPosts() has returned (assuming it is an asynchronous function).

So you should have the data prefetched before reloading the whole tableView is reloaded.