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.

My UITableView consists of 50 sections. Every section has 100 rows, of variable height. At the start I use estimatedRowHeight for fast-loading, but after that when I call scrollToRowAtIndexPath, my UITableView scrolls to the wrong offset. I can understand why this is, because it has an estimatedRowHeight until I scroll the entire table and the proper cell heights are set in the heightForRowAtIndexPath delegate method.

Any solution?

Answer 1

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.