UIScrollView reports wrong targetContentOffset

Number:rdar://46437787 Date Originated:04-Dec-2018 02:04 AM
Status:Open Resolved:
Product:iOS + SDK Product Version:12.1.1
Classification:UI/Usability Reproducible:Always
When implementing the UIScrollViewDelegate method scrollViewWillEndDragging:withVelocity:targetContentOffset: the reported targetContentOffset is wrong if the current contentOffset is in the bouncing area of the scrollView.

Steps to Reproduce:
Build and run the attached sample app.
Drag down to scroll over the top of the first cell in the bouncing area.
Then do a quick flick upwards to scroll down.

Expected Results:
Watch the log. The reported targetContentOffset in scrollViewWillEndDragging:withVelocity:targetContentOffset: should be equal to the final contentOffset when -scrollViewDidEndDecelerating: is called.

Actual Results:
It's not equal.


Also see the attached screen movie and log file.


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