Question ListView mousewheel scrolling speed

In my application, ListViews (UIToolkit runtime 2021.2.0b10) scroll extremely slowly with the mousewheel. I'm not finding a way how to adjust the speed of the scrolling.

According to the documentation, ScrollViews have the "VerticalPageSize" attribute that is supposed to control exactly that, but this parameter is not available in ListViews.

Nevertheless, even changing VerticalPageSize in ScrollViews doesn't have any effect on the scrolling speed either.

Am I missing something, or is it "a work in progress"-topic?

 

What value do you use? Mine is set to 1000.

 

For ScrollView, it doesn't matter, what I set, it doesn't have any impact (I just tried 1000 - no difference).

In ListView I don't have any value to set.

 

I guess you mean here the VerticalPageSize parameter of the ScrollView. That is one issue. Thanks for filing a bug report.

The other issue is the slow scrolling of ListViews. Can you please confirm that I'm not missing something when I don't find a way to change the scroll speed of ListViews?

 

Thank you for this information. Redeclaring the USS variable --unity-metrics-single_line-height in my custom stylesheet did the trick:

:root {
--unity-metrics-single_line-height: 500px;
}

In my case, 500px give a natural scrolling experience. One scroll step moves about one line of the list at 30px item height.

 

Since updateing to The beta we have the same bug.

But on 2021.2.0b15 the workaround seams not to change anything.
No matter what value I set --unity-metrics-single_line-height to, the scroll-speed does not change.

 

Hi, I am having a similar issue can't sense scrolling speed. Is there any more new information? I am using 2021.2.0f1

 

I managed to make it work with a custom callback!

Code (CSharp):

1. [SerializeField] private UIDocument uiDocument;
2.  
3. private float scrollVelocity;
4. private float scrollDamping = 0.1f;
5. private Scroller verticalScroller;
6.  
7. private void Start () {
8.     var rootElement = uiDocument.rootVisualElement
9.     var list = rootElement.Q<ListView>("List");
10.  
11.     verticalScroller = list.Q("unity-content-and-vertical-scroll-container").Q<Scroller>();
12.  
13.     list.RegisterCallback<WheelEvent>(@event => {
14.         scrollVelocity += @event.delta.y * 100;
15.  
16.         // Stop the event here so the builtin scroll functionality of the list doesn't activate
17.         @event.StopPropagation();
18.     });
19. }
20.  
21. private void Update () {
22.     if (verticalScroller != null) {
23.         verticalScroller.value += scrollVelocity;
24.         scrollVelocity -= scrollVelocity * scrollDamping;
25.     }
26. }

 

Any updates here?
It is a real pain :/

:root {
--unity-metrics-single_line-height: 500px;
}

does not work for me either

 

In Unity 2021.2.10f1 I still have trouble setting scrollspeed with ScrollView and ListViews its always veeeery slow

 

Also having this problem. Changing --unity-metrics-single_line-height does nothing. Why is there no communication on this?

 

Setting --unity-metrics-single_line-height used to work with 2021.2.0b10 but as others reported, it stopped working with later versions. With 2021.2.11f1 still no luck.

 

Found the problem.

Before 2021.2.0b15 it used to be enough to set the key --unity-metrics-single_line-height on the root visual element. In later Unity versions, the key must be applied to the parent of the root visual item, which is in my case (runtime) the Panel Settings (check it in the Toolkit Debugger).

I didn't find a way to do this in the UI Builder directly, so I add my stylesheet also to the parent per script on startup:

Code (CSharp):

1. StyleSheet styleSheet = Resources.Load<StyleSheet>("UI/UI-Main");
2.             if (styleSheet != null)
3.                 root.parent.styleSheets.Add(styleSheet);

where root is uiDocument.rootVisualElement.

Now, :root {
--unity-metrics-single_line-height: 500px;
} in the stylesheet is applied correctly.

The scrolling is fast again.

 

Yes, this does appear to work. Thanks!

 

@AlexandreT-unity

This seems to not work in the latest beta 9. I reported the bug. Is there any insight into what is going on? Case #: 1403738

 

You are my HERO! Thanks this works!

 

2021.2.7f1 here and this doesn't work for us (using rootVisualElement or rootVisualElement.parent of runtime UI Document). Our setup has two UI Documents if that makes any difference. Would really appreciate some input from the team on how to make this usable - I had hoped it would be fixed by now - it's an incredibly painful issue.

 

https://issuetracker.unity3d.com/is...scroll-view-scrolling-when-entering-play-mode

 

How do i add:

:root {
--unity-metrics-single_line-height: 500px;
}

into my Project? My Style Sheet from UI Toolkit is named UserInterface. Do i just go into the uss and add the Line at the top? Also i added at ProjectStart the Line:

StyleSheet styleSheet = Resources.Load<StyleSheet>("UI/UserInterface");
if (styleSheet != null)
root.parent.styleSheets.Add(styleSheet)

But nothing is changing when i integrate both into my Project.

 

The same problem has been tested in 2021.3 and 2021.2.16, and still cannot be modified

 

Simple workaround:

Code (CSharp):

1. private ScrollView m_TargetScrollView;
2.  
3. public float ScrollFactor { get; set; } = 100;
4.  
5. private void RegisterCallback()
6. {
7. m_TargetScrollView.RegisterCallback<WheelEvent>((evt) =>
8. {
9.     TargetScrollView.scrollOffset = new Vector2(0, TargetScrollView.scrollOffset.y + ScrollFactor * evt.delta.y);
10. }
11. evt.StopPropagation();
12. }

 

Works Perfectly Thanks !

 

For anyone wondering how to do this, his code is confusing and wrong (or I don't understand the way he did it).

Declare a variable:

Code (CSharp):

1. private ScrollView m_TargetScrollView;

Then in Start(), link it to your element in UIBuilder:

Code (CSharp):

1. m_TargetScrollView = rootUI.Q<ScrollView>("My-ScrollView-Name-example");

Then register a callback to it in start() as well, like so:

Code (CSharp):

1. m_TargetScrollView.RegisterCallback<WheelEvent>((evt) =>
2.         {
3.             m_TargetScrollView.scrollOffset = new Vector2(0, m_TargetScrollView.scrollOffset.y + ScrollFactor * evt.delta.y);
4.             evt.StopPropagation();
5.         }
6.  );

 

It has been 1 year AlexandreT-unity, any chance for a fix?

 

This seems to be different for ScrollView and ListView containers.
For scroll view you can actually use both WheelEvent and --unity-metrics-single_line-height workaround.
For ListView nothing seems to work and you are stuck to whatever is "hardcoded".

 

Incorrect, this is the fix I am currently using for ListView scrolling:

Code (CSharp):

1.    
2.     public static void FixListViewScrollingBug(ListView listView) {
3.         #if UNITY_EDITOR
4.             var scroller = listView.Q<Scroller>();
5.             listView.RegisterCallback<WheelEvent>(@event => {
6.                 scroller.value +=  @event.delta.y * 100;
7.                 @event.StopPropagation();
8.             });
9.         #else
10.             var scroller = listView.Q<Scroller>();
11.             listView.RegisterCallback<WheelEvent>(@event => {
12.                 scroller.value -=  @event.delta.y * 10000;
13.                 @event.StopPropagation();
14.             });
15.         #endif
16.     }
17.  

It seems like the behavior is different In the build vs the editor. Just noticed actually that the behavior is also different on a windows build compared to a linux build. So I will be adding a third section for that case rofl

 

This is so broken I can't believe it...
But thanks for the solution.

 

Allow me to echo my frustration with this defect along with the rest of you. This has been very user unfriendly. That being said, I understand the position Unity is in. It is incredibly difficult to ship features and keep everyone happy without breaking stride. We are fortunate that the community is filled with talented individuals like yourselves to supply solutions and workarounds. I have tried every suggestion in here, and the above is the one that worked for me. Happy Coding.

 

I was able to change the scroll speed using StripeGuy's fix above.
Note this issue first appeared for me only after I added an EventSystem because I needed to use a legacy Canvas-based UI in the project as well as UIElements. With the EventSystem disabled, scroll speed is normal. When the EventSystem is enabled, I need to use the scroll view multiplier code above to get decent scroll speeds.
Using Unity 2021.3.5f1.

 

Maybe your issue is fixed if you use 2021.3.22f1 instead.
https://issuetracker.unity3d.com/is...rolling-when-entering-play-mode-and-in-builds

 

Just to confirm what @conor_saber mentioned, I had an EventSystem I didn't need to use in this project, on disabling the EventSystem the scroll speed is fine.