Prevent Uitableview Scrolling Below a Certain Point

Prevent UITableView scrolling below a certain point

You can use the property contentInset of UITableView just for that. Just remember to set them with minus values, cause we are shrinking the content size:

CGFloat insetTop = topAllowedRow * c_CELL_HEIGHT * -1;
CGFloat insetBottom = bottomAllowedRow * c_CELL_HEIGHT * -1;
[self.tableView setContentInset:UIEdgeInsetsMake(insetTop, 0, insetBottom, 0)];

The other solution is to implement UIScrollViewDelegate method scrollViewDidScroll: and when scrollView.contentOffset is too huge, set it back to the max value that user can scroll to:

- (void)scrollViewDidScroll:(UIScrollView*)scrollView {
    CGPoint scrollViewOffset = scrollView.contentOffset;
    if (scrollViewOffset.x > MAX_VALUE) {
        scrollViewOffset.x = MAX_VALUE;
    }
    [scrollView setContentOffset:scrollViewOffset];
}

First solution has both the advantage and disadvantage since then UIScrollView will manage the bouncing (just like in pull to refresh). It's more natural and HIG-compatible, but if you really need user not to see below the certain row, use delegate method.

How do I stop UITableview from scrolling more than one cell at a time

Thanks for your response. Here is how I solved it. I set:

  tableView.isScrollEnabled = false // Set the tableview scroll enabled to false

Then in the "cellForRowAt indexPath: IndexPath" function I saved the indexPath of the first row to the currentIndexPath property :

  currentIndexPath = indexPath

Then I added a gesture recognizer to the tableview for swiping up:

   let swipeToNextVideoGesture = UISwipeGestureRecognizer(target: self, action: 
    #selector(swipeToNext(_:)))
    swipeToNextVideoGesture.direction = .up
    tableView.addGestureRecognizer(swipeToNextVideoGesture)

Then in the function I first checked if the next Row is in the tableview datasource array bounds, then I scrolled to that row:

    @objc private func swipeToNext(_ gesture: UISwipeGestureRecognizer) {
    let nextVideoIndexPath = currentIndexPath.row+1
    if !(nextVideoIndexPath >= viewModel.postInformations.count) {
        currentIndexPath = IndexPath(row: nextVideoIndexPath, section: indexPathSection)
        tableView.scrollToRow(at: currentIndexPath, at: .none, animated: true)
    }
}

How to prevent a UITableView from being pulled down past a certain point?

Try this

extension ViewController: UIScrollViewDelegate
{
   func scrollViewDidScroll(_ scrollView: UIScrollView)
   {

    print("ddffddfd \(scrollView.contentOffset.y)")

    if scrollView.contentOffset.y > 0 && imageContainerViewHeightConstraint.constant == 223
    {
        return
    }

    if scrollView.contentOffset.y > 0
    {

        var sd = imageContainerViewHeightConstraint.constant + abs(scrollView.contentOffset.y)

        if(sd < 233 )
        {

            print("path111    1")

              self.dataTableView.contentOffset = CGPoint.init(x: 0, y: 0  )

            return

        }
        else
        {
             print("path111    2")
             imageContainerViewHeightConstraint.constant -= abs(scrollView.contentOffset.y)
        }

         print("path11111    3")
        view.layoutIfNeeded()

         self.dataTableView.contentOffset = CGPoint.init(x: 0, y: 0  )
        return
    }

     print("path11111   4")

    if scrollView.contentOffset.y < 0 && imageContainerViewHeightConstraint.constant >= initialContainerImageViewHeight * 2
    {
        self.dataTableView.contentOffset = CGPoint.init(x: 0, y: 0  )

        //self.dataTableView.bounces = false

        return
    }
    else
    {
        imageContainerViewHeightConstraint.constant += abs(scrollView.contentOffset.y)

         view.layoutIfNeeded()

    }

   }

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

    func scrollViewDidEndDecelerating(_ scrollView: UIScrollView)
    {
        resetContainerViewSize()
    }
}

///////

func resetContainerViewSize()
{
    imageContainerViewHeightConstraint.constant = 223

    UIView.animate(withDuration: 0.7,
                   delay: 0.0,
                   usingSpringWithDamping: 0.7,
                   initialSpringVelocity: 0.5,
                   options: .curveEaseInOut,
                   animations: {
                    self.view.layoutIfNeeded()   
                    self.dataTableView.bounces = true
                }, completion: nil)
}

In Action

Find a demo here testScrollAboveTable

Prevent UITableView from scrolling when new cells are inserted

func add(_ item: Item) {
    // Calculate your `contentOffset` before adding new row
    let additionalHeight = tableView.contentSize.height - tableView.frame.size.height
    let yOffset = tableView.contentOffset.y

    // Update your contentInset to start tableView from bottom of page
    updateTableContentInset()

    items.append(item)       

    // Create indexPath and add new row at the end
    let indexPath = IndexPath(row: objects.count - 1, section: 0)
    tableView.insertRows(at: [indexPath], with: .top)

    // Scroll to new added row if you are viewing latest messages otherwise stay at where you are
    if yOffset >= additionalHeight {
        tableView.scrollToRow(at: indexPath, at: .top, animated: true)
    }
}

Here is the method to update contentInset. It will give you the same effect which you were achieving by this CGAffineTransform(scaleX: 1, y: -1)

func updateTableContentInset() {
    var contentInsetTop = tableView.frame.size.height - tableView.contentSize.height
    if contentInsetTop <= 0 {
        contentInsetTop = 0
    }
    tableView.contentInset = UIEdgeInsets(top: contentInsetTop, left: 0, bottom: 0, right: 0)
}

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