Question NextFrameAsync vs EndOfFrameAsync

So, I have this code:

Code (csharp):

1.  
2.         private void changeMode(FocusMode focus)
3.         {
4.  
5.             if (focus == activeFocus)
6.             {
7.                 return;
8.             }
9.  
10.  
11.             panels[(int)activeFocus].RemoveFromClassList("mode-selected");
12.            activeFocus = focus;
13.            panels[(int)activeFocus].AddToClassList("mode-selected");
14.             ...
15.  
16.             _ = modeChange();
17.  
18.         }
19.        
20.        private async Awaitable modeChange()
21.         {
22.             await Awaitable.EndOfFrameAsync();  
23.             selectFocus(activeFocus);
24.            ...
25.        }
26.  

Basically what it does is wait for the panel to be visible ("display: none" removed) and then focus on the first visible element.

That works but when I used Awaitable.NextFrameAsync() it didn't work, the panel was not visible yet. Isn't it counter-intuitive that the changes are performed in EndOfFrameAsync() and not in NextFrameAsync()?

 

UI Toolkit visual elements are updated towards the end of the player loop. I imagine NextFrameAsync is taking place before visual elements are updated, while EndOfFrameAsync does take place after.

So it depends when this code runs. If it's running as the visual element is updated, NextFrameAsync is before the next time visual elements will be updated.

 

Yeah I think so too. You'd think that the end of the frame is before the next frame though.

 

I suspect you were affected by this bug where NextFrameAsync does not wait until next frame.

https://issuetracker.unity3d.com/is...using-the-awaitable-dot-nextframeasync-method