将refreshControl添加到collectionViewCell中的collectionView

Question

我有一个带有3个单元格的UICollectionViewController（HomeViewController）  每个单元格都与屏幕尺寸一样大。 在最后一个单元格中，我有另一个UICollectionView（collectionView）来显示数据 每次刷新时都应该刷新这些数据。

但这不起作用。

这是到目前为止的代码：

HomeViewController

class HomeViewController: UICollectionViewController, UICollectionViewDelegateFlowLayout {


    let thirdCellId = "thirdCell"


    override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
            let thirdCell = collectionView.dequeueReusableCell(withReuseIdentifier: thirdCellId, for: indexPath) as! ThirdCell

            thirdCell.refreshControl.addTarget(self, action: #selector(refreshData), for: UIControlEvents.valueChanged)

            return thirdCell
    }


    @objc func refreshData(sender: UIRefreshControl) {

        let cell = sender.superview as! ThirdCell  <--- gives error: Could not cast value of type 'UICollectionView' to 'ExploreCell'

        cell.loadData() 
        cell.refreshControl.endRefreshing()

        print("Did work")
    }

}

ThirdCell 代码：

class ThirdCell: UICollectionViewCell, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout {


override init(frame: CGRect) {
    super .init(frame: frame)

    setupCollectionView()
    loadData()
    setupRefreshControl()
}


// --- CollectionView --- 


    lazy var collectionView: UICollectionView = {
        let layout = UICollectionViewFlowLayout()
        let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
        cv.delegate = self
        cv.dataSource = self
        return cv
    }()


    func setupCollectionView() {
        self.addSubview(collectionView)
        // Setup constraints
    }


// --- RefreshControl --- 


    var refreshControl: UIRefreshControl = {
        let rfs = UIRefreshControl()
        // Handle action in HomeViewController
        return rfs
    }()


    func setupRefreshControl() {
        if #available(iOS 10.0, *) {
            collectionView.refreshControl = refreshControl
        } else {
            collectionView.addSubview(refreshControl)
        }
        refreshControl.centerXAnchor.constraint(equalTo: self.centerXAnchor).isActive = true
        refreshControl.bottomAnchor.constraint(equalTo: self.topAnchor, constant: 30).isActive = true
        refreshControl.translatesAutoresizingMaskIntoConstraints = false
    }



    func loadData() {
        // Load data
        self.collectionView.reloadData()
    }


    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

}