Styjun

I have a UIViewController, inside which there is a tableView. I added a RefreshControl. But when I pull, it always jumps for some times, which is not smooth and continuous at all.

I'm using Swift 4 and Xcode 10.1.

class ItemsController: UIViewController, UITableViewDelegate, UITableViewDataSource, UITextViewDelegate, ItemCellDelegate 
 ......
 lazy var refreshControl: UIRefreshControl = 
 let refreshControl = UIRefreshControl()
 refreshControl.addTarget(self, action:
 #selector(handleRefresh(_:)),
 for: UIControl.Event.valueChanged)
 refreshControl.tintColor = UIColor.lightGray

 return refreshControl
 ()
 ......
 override func viewDidLoad() 
 // Refresh
 self.tableView.refreshControl = self.refreshControl
 
 ......
 @objc func handleRefresh(_ refreshControl: UIRefreshControl) 
 loadData()
 self.tableView.reloadData()
 refreshControl.endRefreshing()
 
 ......

I also faced that kind of problem. You can use this approach below:

1. 
   

   Change your handleRefresh method like this:

   
   
   

   @objc func handleRefresh(_ refreshControl: UIRefreshControl) 
    if !tableView.isDragging 
    refresh() // refresh is another method for your reloading jobs
    
   
   
   

   
   


2. 
   

   Add refresh method.

   
   
   

   func refresh() 
    self.refreshControl.endRefreshing()
    self.tableView.reloadData()
   
   

   
   


3. 
   

   Lastly you need to implement scrollViewDidEndDragging. If you've pulled down far enough, the refreshControl will be refreshing, so call refresh. Otherwise, you either haven't pulled down far enough, you were dragging on a different part of the table, or you dragged so quickly that the refreshControl ValueChanged event has yet to fire, and it will refresh the table there.

   
   
   

   func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) 
    if refreshControl.isRefreshing == true 
    refresh()
    
    
   

   
   

Is loadData() asynchronous? because if so it should have a completion handler and

tableView.reloadData()
refreshControl.endRefreshing()

should be done (on the main thread) from there. Otherwise what is happening is the user pulls down and you instantly update the tableView and stop the refresh control, so thats why you have no animation.

try

@objc func handleRefresh(_ refreshControl: UIRefreshControl) {
 loadData()
 self.tableView.reloadData()
 DispatchQueue.main.async 
 //DispatchQueue.main.asyncAfter(deadline: .now + 0.2) // or this one with 
 //short delay
 refreshControl.endRefreshing()
 

I just solved this problem by doing this:

@objc func handleRefresh(_ refreshControl: UIRefreshControl) 

 refreshControl.endRefreshing()


func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) 

 loadData()

Pretty simple. Now the animation is much better.
The tableView.reloadData(), which is inside of loadData(), is getting the animation less smooth. So I make it do after the user releases from dragging.