How to use pull to refresh in Swift?

A solution with storyboard and Swift:

1. Open your .storyboard file, select a TableViewController in your storyboard and "Enable" the Table View Controller: Refreshing feature in the Utilities.

   

2. Open the associated UITableViewController class and add the following Swift 5 line into the viewDidLoad method.

   self.refreshControl?.addTarget(self, action: #selector(refresh), for: UIControl.Event.valueChanged)
   

3. Add the following method above the viewDidLoad method

   func refresh(sender:AnyObject)
   {
       // Updating your data here...
   
       self.tableView.reloadData()
       self.refreshControl?.endRefreshing()
   }
   

UIRefreshControl is directly supported in each of UICollectionView, UITableView and UIScrollView (requires iOS 10+)!

Each one of these views has a refreshControl instance property, which means that there is no longer a need to add it as a subview in your scroll view, all you have to do is:

@IBOutlet weak var collectionView: UICollectionView!

override func viewDidLoad() {
    super.viewDidLoad()
    
    let refreshControl = UIRefreshControl()
    refreshControl.addTarget(self, action: #selector(doSomething), for: .valueChanged)
    
    // this is the replacement of implementing: "collectionView.addSubview(refreshControl)"
    collectionView.refreshControl = refreshControl
}

@objc func doSomething(refreshControl: UIRefreshControl) {
    print("Hello World!")
    
    // somewhere in your code you might need to call:
    refreshControl.endRefreshing()
}

Personally, I find it more natural to treat it as a property for scroll view more than adding it as a subview, especially because the only appropriate view to be as a superview for a UIRefreshControl is a scrollview, i.e the functionality of using UIRefreshControl is only useful when working with a scroll view; That's why this approach should be more obvious to set up the refresh control view.

However, you still have the option of using the addSubview based on the iOS version:

if #available(iOS 10.0, *) {
  collectionView.refreshControl = refreshControl
} else {
  collectionView.addSubview(refreshControl)
}

Pull to refresh is built in iOS. You could do this in swift like

let refreshControl = UIRefreshControl()

override func viewDidLoad() {
   super.viewDidLoad()

   refreshControl.attributedTitle = NSAttributedString(string: "Pull to refresh")
   refreshControl.addTarget(self, action: #selector(self.refresh(_:)), for: .valueChanged)
   tableView.addSubview(refreshControl) // not required when using UITableViewController
}

@objc func refresh(_ sender: AnyObject) {
   // Code to refresh table view  
}

At some point you could end refreshing.

refreshControl.endRefreshing()