Refreshable.swift

@objc protocol Refreshable
{
	/// The refresh control
	var refreshControl: UIRefreshControl? { get set }
	
	/// The table view
	var tableView: UITableView! { get set }
	
	/// the function to call when the user pulls down to refresh
	@objc func handleRefresh(_ sender: Any);
}


extension Refreshable where Self: UIViewController
{
	/// Install the refresh control on the table view
	func installRefreshControl()
	{
		let refreshControl = UIRefreshControl()
		refreshControl.tintColor = .primaryColor
		refreshControl.addTarget(self, action: #selector(handleRefresh(_:)), for: .valueChanged)
		self.refreshControl = refreshControl
		
		if #available(iOS 10.0, *)
		{
			tableView.refreshControl = refreshControl
		}
		else
		{
			tableView.backgroundView = refreshControl
		}
	}
}

My code is very likely to these, and now I have a ViewController, which uses UICollectionView. Since any kind of scroll view has the property refreshControl since iOS 10, I want to extend my protocol so that the view can be UIScrollView or its subclass. But I can't figure out how to achieve that.

@aalenliang, u just need to change the tableView property to a scrollView property on your protocol and add scrollView.refreshControl = refreshControl