5

Sometimes I see white background for text fields of the question (with fav tags) in the questions list:

bgfav

Recently I've got same (but with inverted colors) issue with no fav tags question:

bgnofav

After manual refresh block draws correctly.

Seems question background colors used from an another (next to buggy) question in the list. In both situations fav tagged question lays near the not-fav one.

Steps to reproduce (more easily in SO):

  1. Select question with fav tags (blue background) in the list.
  2. Reload question list via swipe at the top of the list (new question must be in the list).
  3. Find previously selected question.
  4. Select another question near already selected.

  • App Version: 1.6.0.10 / 1.6.1.2 / 1.6.2.5
  • Device: iPad Air 2 (Wi-Fi)
  • OS Version: Version 10.0.2 (Build 14A456) / 10.1.1 (Build 14B100) / 10.2 (Build 14C92)
3

This will be fixed in 1.6.6.1.

The problem has to do with some weird technical details of iOS. If a label has an opaque background, its text gets rendered onto that background. It's then faster for the GPU to draw because it can just draw the layer without blending it onto whatever image is below. This is complicated by the fact that the background color of a table cell changes, sometimes instantaneously, sometimes in an animated fade.

To handle this, when moving from a unselected to selected, the UI framework saves the background color of every layer and sets the background as transparent. When it finishes animating back to unselected, it restores all the colors.

The problem is happening somewhere in this process. We're reloading the table view and selecting the cell in quick succession and somehow the system is losing track of the colors to reapply. To compensate for this, I'm updating the label's colors every time there's a non-animated change to selected.

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