New swift code changed in calling action method you could do rewrite like this

@IBOutlet weak var collectionView: UICollectionView!var refresher:UIRefreshControl!override func viewDidLoad() {   super.viewDidLoad()    self.refresher = UIRefreshControl()    self.collectionView!.alwaysBounceVertical = true    self.refresher.tintColor = UIColor.red    self.refresher.addTarget(self, action: #selector(loadData), for: .valueChanged)    self.collectionView!.addSubview(refresher)}func loadData() {   self.collectionView!.refreshControl.beginRefreshing()   //code to execute during refresher       .       .       .   stopRefresher()         //Call this to stop refresher }func stopRefresher() {   self.collectionView!.refreshControl.endRefreshing() }

var refreshControl:UIRefreshControl!override func viewDidLoad() {    super.viewDidLoad()      self.refreshControl = UIRefreshControl()      self.refreshControl.attributedTitle = NSAttributedString(string: "Pull to refresh")     self.refreshControl.addTarget(self, action: #selector(PricingPlansCollectionViewController.reload), for: .valueChanged)      collectionView!.addSubview(refreshControl)} func refresh(sender:AnyObject)  {    //DO   }

Swift 5 solution

As @fishspy already mentioned, that's the way to put your collection view inside a view controller, but I'm gonna share also how to connect your refresh control to the collection view in a cleaner way.

Since iOS 10 there's a dedicated property for the refresh control. Apart of that, I'd also recommend to directly initialise your refresh control as a property, declaring it private and doing the following things:

@IBOutlet private weak var collectionView: UICollectionView!private let refreshControl = UIRefreshControl()override func viewDidLoad() {    super.viewDidLoad()    refreshControl.addTarget(self, action: #selector(didPullToRefresh(_:)), for: .valueChanged)    collectionView.alwaysBounceVertical = true    collectionView.refreshControl = refreshControl // iOS 10+}@objcprivate func didPullToRefresh(_ sender: Any) {    // Do you your api calls in here, and then asynchronously remember to stop the    // refreshing when you've got a result (either positive or negative)    refreshControl.endRefreshing()}