UITableView jumpy on scroll after changing cell height - ios

Question

So I have a tableView where I want to change the height of a cell when tapped. Well, actually, I am replacing it with a bigger cell.
On tap, I call:
tableView.beginUpdates()
tableView.reloadRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
tableView.endUpdate()
And then I modify my cellForRowAtIndexPath to return the right new cell and height. The cell's height is being automatically calculated by overriding sizeThatFits in the cell's implementation:
override func sizeThatFits(size: CGSize) -> CGSize {
return CGSizeMake(size.width, myHeight)
}
Oddly enough, after I do this, scrolling downwards is fine, but when I scroll upwards, the table jumps 5 or so pixels every second until I reach the top. After I reach the top of the table, the problem is gone and there is no jumping going in either direction. Any idea why this is happening? I imagine it has something to do with the new cell height displacing the other cells, but I can't see why the tableView is not taking care of this. Any help is appreciated!
Thanks!
EDIT: Added code from cellForRowAtIndexPath:
if self.openedCellIndex != nil && self.openedCellIndex == indexPath {
cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as ListCell
(cell as ListCell).updateWithDetailView(dayViewController!.view)
} else {
cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as ListCell
(cell as ListCell).updateWithData(eventDay: store.events![indexPath.row], reminderDay: store.reminders![indexPath.row])
}
return cell

Answer 1

You should include your code for cellForRow and heightForRow, but I will give it a blind shot.
When a cell is tapped in cellForRow you should store the index of that cell, then reload the data or just that cell. Then in heightForRow use if(yourTappedCell){return preferredHeight;}

Answer 2

Unfortunately, there does not seem to be a simple answer to this. I have struggled with it on multiple iOS apps.
The only solution I have found is to programmatically scroll to the top of your UITableView once it appears again.
[self.tableView setContentOffset:CGPointMake(0, 0 - self.tableView.contentInset.top) animated:YES];
OR
self.tableView.contentOffset = CGPointMake(0, 0 - self.tableView.contentInset.top);
Hope this an acceptable work around while still being able to use dynamic cell heights =)

Answer 3

func refreshCellState(indexPath:IndexPath) {
guard let cell = tableView.cellForRow(at: indexPath) as? ListCell else {
return
}
if self.openedCellIndex != nil && self.openedCellIndex == indexPath {
cell.updateWithDetailView(dayViewController!.view)
} else {
cell.updateWithData(eventDay: store.events![indexPath.row], reminderDay: store.reminders![indexPath.row])
}
self.tableView.beginUpdates()
self.tableView.endUpdates()
if #available(iOS 11.0, *) {
self.tableView.performBatchUpdates {
} completion: { complete in
if complete {
self.tableView.scrollToRow(at: indexPath, at: .none, animated: true)
}
}
} else {
// Fallback on earlier versions
self.tableView.reloadData()
}
}
Here, Dont reload that cell entirely, But take that cell when clicked and provide data to cell from there.
Now call begin and endUpdated methods of tableview to update height.