UIScrollViews setContentOffset: behaves different than setContentOffset:animated:NO

Originator:markus
Number:rdar://16724593 Date Originated:25-Apr-2014 03:09 PM
Status:Open Resolved:
Product:iOS SDK Product Version:6.1 / 7.1
Classification:Other Bug Reproducible:Always
 
Summary:
UIScrollViews setContentOffset: behaves different than setContentOffset:animated:NO. You would expect, that it behaves the same when animated:NO is given. You would even expect, that one method calls the other one.

Actually setContentOffset: just changes the offset without canceling any running animation/deceleration. setContentOffset:animated: on the other hand actually stops any running animation, but ONLY when animated:NO is given.

Steps to Reproduce:
Build a UITableView with a lot of cells, e.g. 2000. Scroll, so the scrollView keeps scrolling after you lift your finger. Call setContentOffset: or setContentOffset:animated:NO during the time, when it still scrolls.

Expected Results:
You would expect on any manual change, that the animation will be stopped.

Actual Results:
The animation is ONLY stopped when calling setContentOffset:animated:NO, but NOT when using setContentOffset: or setContentOffset:animated:YES

Regression:
Tested in 6.1 and 7.1.1, probably the same in earlier versions

Notes:
Stackoverflow has some related questions, e.g. http://stackoverflow.com/questions/3410777/how-can-i-programmatically-force-stop-scrolling-in-a-uiscrollview/23290943

The behavior should at least be documented. That's not the case currently.

Comments

Apple asked for an example project

I provided this as an example: http://cl.ly/1H3x2p2h0f43

By markus at April 29, 2014, 10:05 a.m. (reply...)

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