UITableView hides cell before it is animated off-screen.

Originator:sven.titgemeyer
Number:rdar://39678172 Date Originated:24-Apr-2018 11:16 AM
Status:Open Resolved:
Product:iOS + SDK Product Version:11.3
Classification:Other Bug Reproducible:Always
 
Area:
UIKit

Summary:
When setting a new `tableHeaderView` on `UITableView` inside an animation block the cells are animated off-screen, but cells that will be off-screen after the animation completes are removed before the animation starts.

In the sample I change the frame of the `tableHeaderView` and set the new (updated) `tableHeaderView` inside an animation block. 

See video and sample attached.

Steps to Reproduce:

1. Run the attached sample.
2. Tap `Change tableHeaderView size.

Expected Results:
The frame change of `tableHeaderView` is animated. The cells move to the bottom.

Actual Results:
The last cell just disappears without animation. Does only happen if the cell would be completely off-screen after animation finishes.

Version/Build:
11.3 (15E217)

Configuration:

Comments

Gif showing the bug:

https://gfycat.com/SphericalBadHadrosaurus

By sven.titgemeyer at April 24, 2018, 9:42 a.m. (reply...)

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