UITableView scrollToRowAtIndexPath scrolls to wrong offset with estimatedRowHeight on iOS 7

Question

I am using the estimatedRowHeight method from UITableView in iOS 7, which works perfectly for fast loading of a UITableView with 5000 rows of variable heights.

Answer 1

Mine was wrong because the "atScrollPosition" was set to UITableViewScrollPositionNone - change it to UITableViewScrollPositionMiddle and it should work fine

Answer 2

This solved my problem

let oldContentSize = tableView.contentSize
tableView.scrollToRow(at: indexPath, at: .top, animated: true)
// Called again when tableView contentSize change
if !tableView.contentSize.equalTo(oldContentSize) {
    tableView.scrollToRow(at: indexPath, at: .top, animated: true)
}

Answer 3

Unfortunately this issue is to be expected when using estimatedRowHeight in your code with such a low value. When you scrollToRowAtIndexPath it does not actively calculating the correct size as you go. The underlying cause is, if you scrolled from Section 1 to Section 2, it could feasibly calculate the correct position on the fly and the estimatedRowHeight of the cells if it was a relatively new device. Any older devices would be brought to their knees, and even any new ones would be as well if you had to process 5000 cells, for example.

A maybe-solution to your problem could be to increase the estimatedRowHeight constant so the device doesn't have to do as much work.