Tableview getting jerk when inserting new cell on scrolling

🎤 General Discussion Swift
1

I am inserting new row at 0 locations when user scrolls down. but tableview is getting jerk little. Below is my code.

class SearchViewController: UIViewController,UITableViewDelegate,UITableViewDataSource,UIScrollViewDelegate {

@IBOutlet weak var tableView: UITableView!
var chatItems:NSMutableArray = []

var endDraggingPoint:CGFloat = 0;

var beginDraggingPoint:CGFloat = 0;

override func viewDidLoad() {
    super.viewDidLoad()

    // Do any additional setup after loading the view.

    chatItems = ["SearchBarCell","ChatCell"];

    for value in 1...100{

        chatItems.add(String(value))

    }

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

//MARK: - Tableview delegate Methods

 func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int
 {
    return chatItems.count
}

// Row display. Implementers should *always* try to reuse cells by setting each cell's reuseIdentifier and querying for available reusable cells with dequeueReusableCellWithIdentifier:
// Cell gets various attributes set automatically based on table (separators) and data source (accessory views, editing controls)

 func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell
 {

    var cell:UITableViewCell!

    var cellIdentyfier: NSString

    let itemName:NSString = chatItems.object(at: indexPath.row) as! NSString;

    if itemName == "SearchBarCell"
    {
        cellIdentyfier = "SearchBarCell"

    }else if itemName == "ArchiveLabelCell" {
        cellIdentyfier = "ArchiveLabelCell"
    }else {
        cellIdentyfier = "ChatCell"
    }

    cell = tableView.dequeueReusableCell(withIdentifier: cellIdentyfier as String)

    if(cell == nil)
    {
        cell = UITableViewCell(style: UITableViewCellStyle.default,reuseIdentifier:cellIdentyfier as String)
    }

    return cell;
}

func scrollViewDidScroll(_ scrollView: UIScrollView)
{
    print("scrollViewDidScroll: \(scrollView.contentOffset.y)");

    if endDraggingPoint == 0 && scrollView.contentOffset.y <= -30 {

        self.addArchiveCell(scrollView: scrollView);

    }else if scrollView.contentOffset.y > 50 {

        self.removeArchiveCell(scrollView: scrollView)
    }
}

func removeArchiveCell(scrollView:UIScrollView) {

    if chatItems.contains("ArchiveLabelCell") {
        print("Removing archive cell: \(scrollView.contentOffset.y)");
        chatItems.removeObject(at: 0);
        tableView.deleteRows(at: [IndexPath.init(row: 0, section: 0)], with: .none)
    }
}

func addArchiveCell(scrollView:UIScrollView) {

    if beginDraggingPoint <= 50 {

        if !chatItems.contains("ArchiveLabelCell") {
            self.chatItems.insert("ArchiveLabelCell", at: 0)
            print("Adding archive cell: \(scrollView.contentOffset.y)");
            //self.tableView.beginUpdates()
            self.tableView.insertRows(at: [IndexPath.init(row: 0, section: 0)], with: .none)
            //self.tableView.endUpdates()

        }
    }
}

func scrollViewWillBeginDragging(_ scrollView: UIScrollView)
{
    endDraggingPoint = 0
    beginDraggingPoint = scrollView.contentOffset.y

}

}

Can somebody tell me why tableview getting jerk while scrolling down and inserting new row?

2

Hi @shankarphadatar,
to try to solve your problem, if you are trying to add a row to a table, have you tried to add these by specifying the code of adding rows between a tableView.beginUpdates and tableView.endUpdates

cheers,

Jayant