Slider OnValueChanged not working at runtime

In Unity 2020.1 the OnValueChanged callback of the Slider component seems to refuse to work at runtime.

I've basically written this bridge between a Slider and a Text showing its value multiple times for different projects already and I thought I was quite familiar with the technique. However, in Unity 2020.1 the usual approach doesn't seem to work.
The script basically has a current and a max value (f.e. for a player's health value) and sets the TextMeshProUGUI text property to a formatted string whenever the value of the Slider changes.
However, this approach no longer seems to function, no matter how I set the text (text = ... or SetText(...) ) or what the callback in the script looks like (usually, I just do this in the set{} blocks of public properties).

I've uploaded a short video of the behaviour in editor and at runtime and attached it below. In the code, I have omitted any Debug.Log calls.

Code (CSharp):

1. public class UIResourceText : TextMeshProUGUI {
2.     float currentValue = 1000, maxValue = 1000;
3.     public string formatString;
4.  
5.     new void Awake(){
6.         base.Awake();
7.         formatString = text;
8.     }
9.  
10.     public float CurrentValue {
11.         get { return currentValue; }
12.         set { currentValue = Mathf.Clamp(value, 0, maxValue); }
13.     }
14.  
15.     public float MaxValue {
16.         get { return maxValue; }
17.         set { maxValue = Mathf.Clamp(value, 0, float.MaxValue); }
18.     }
19.  
20.     public void SetCurrentValue(float value){
21.         CurrentValue = value;
22.         UpdateText();
23.     }
24.  
25.     public void SetMaxValue(float value){
26.         MaxValue = value;
27.         UpdateText();
28.     }
29.  
30.     public void SetText(float value){
31.         text = string.Format("{0} / {1}", value, maxValue);
32.     }
33.  
34.     void UpdateText(){
35.         base.SetText("{0} / {1}", currentValue, maxValue);
36.     }
37. }

 

I am reporting the same thing did you ever find a fix?

EDIT: No "fix" found. I updated unity to the newest version. Still had the same problem. Code worked in editor would not work at run time.

Fast forward two days. Think this is an actually a unity bug. Try to recreate problem in empty project, same code works without any changes. Go back to original project and try it again there, now it works in editor and runtime.

 

Fast forward seven months, and I think this is an actual Unity bug too. I'm having the same issue. It works only if the event is set to 'Editor And Runtime'.

 

Er, this is a bit bizarre, I'm seeing this in Unity 2019.4.25f1 with an in-game volume slider that has been working fine in-production via a Runtime-only OnValueChanged event callback. If I'm in play mode and simply toggle the event to 'Editor and Runtime' and then back to 'Runtime' it magically starts working as expected!?

 

Very odd, yeah, while in play mode I can also toggle the event to Off then back to Runtime or I can toggle whether the slider is interactive and those redundant actions seem to kick it into working - definitely seems like a Unity bug here.

 

Apparently _any_change to the slider while in play mode (even just changing the 'normal' color) is enough to kick the slider in to working.

Ah, okey - I did recently turn on the "experimental" editor optimization for being able to transition into play mode faster by disabling the 'domain reload'. Turning that off under Project Settings -> Editor -> Enter Play Mode Settings actually fixes this issue for me.

I guess then that there's some static state in Unity's slider implementation and it maybe needs updating to support this play mode optimization.

 

Strange thing but as @Rib said, doing this Project Settings -> Editor -> Enter Play Mode Settings actually fixes this issue for me.

 

@Rib is right on point.