Version: 2021.3+
This example demonstrates how to create simple transitions that are triggered by pseudo-classes and C# events.
The example creates a custom Editor window with three labels that rotate and scale when you hover over them. The transition lasts for three seconds.
You can find the completed files that this example creates in this GitHub repository.
This guide is for developers familiar with the Unity Editor, UI(User Interface) Allows a user to interact with your application. Unity currently supports three UI systems. More info
See in Glossary Toolkit, and C# scripting. Before you start, get familiar with the following:
Use the menu to create the Editor window files with three default labels.
Create a Unity project with any template.
Create a folder named create-a-transition
to store the files for this example.
In that folder, right-click in the Project window and select Create > UI Toolkit > Editor Window.
In the C# box, enter TransitionExample
. This creates the following files:
TransitionExample.cs
TransitionExample.uss
TransitionExample.uxml
In UI Builder, use the StyleSheets window to create a hover style for the label, which triggers the transition. Set the transition on the label rather than the hover. If you set the transition on the hover, the transition doesn’t work if the cursor leaves the label.
Open TransitionExample.uxml
in the UI Builder.
In the StyleSheets window, click Add new selector and enter Label:hover
to add a hover style for the label.
Press Enter and select Label:hover in the list of USS selectors.
1.1
.10
.In the StyleSheets window, click Add new selector and enter Label
to add a style for the label.
Press Enter and select Label in the list of USS selectors.
In the Transition Animations section, enter 3
in the Duration row.
Save and close the UI Builder. Your TransitionExample.uss
file looks like the following:
.custom-label { font-size: 20px; -unity-font-style: bold; color: rgb(68, 138, 255); } Label:hover { scale: 1.1 1; rotate: 10deg; } Label { transition-duration: 3s; }
In Unity, select Window > UI Toolkit > Transition Example.
Hover over the second and third labels. The labels rotate and increase in size over three seconds.
In C#, create the same transition you did in the previous section for the first label. Use the pointer events to trigger the transition.
Open TransitionExample.cs
in a text editor.
Replace the contents of TransitionExample.cs
with the following:
using UnityEditor; using UnityEngine; using UnityEngine.UIElements; using System.Collections.Generic; public class TransitionExample : EditorWindow { [SerializeField] VisualTreeAsset m_VisualTreeAsset; [MenuItem("Window/UI Toolkit/TransitionExample")] public static void ShowExample() { TransitionExample wnd = GetWindow<TransitionExample>(); wnd.titleContent = new GUIContent("Transition Example"); } public void CreateGUI() { // Each editor window contains a root VisualElement object. VisualElement root = rootVisualElement; // VisualElements objects can contain other VisualElement following a tree hierarchy. cSharpLabel = new Label("Hello World! From C#"); root.Add(cSharpLabel); // Create transition on the new Label. cSharpLabel.style.transitionDuration = new List<TimeValue>{ new TimeValue(3) }; // Record default rotate and scale values. defaultRotate = cSharpLabel.resolvedStyle.rotate; defaultScale = cSharpLabel.resolvedStyle.scale; // Set up event handlers to simulate the use of the :hover pseudo-class. cSharpLabel.RegisterCallback<PointerOverEvent>(OnPointerOver); cSharpLabel.RegisterCallback<PointerOutEvent>(OnPointerOut); // Instantiate UXML VisualElement labelFromUXML = m_VisualTreeAsset.Instantiate(); root.Add(labelFromUXML); } // The Label created with C#. VisualElement cSharpLabel; // The default rotate and scale values for the new Label. Rotate defaultRotate; Scale defaultScale; void OnPointerOver(PointerOverEvent evt) { SetHover(evt.currentTarget as VisualElement, true); } void OnPointerOut(PointerOutEvent evt) { SetHover(evt.currentTarget as VisualElement, false); } // When the user enters or exits the Label, set the rotate and scale. void SetHover(VisualElement label, bool hover) { label.style.rotate = hover ? new(Angle.Degrees(10)) : defaultRotate; label.style.scale = hover ? new Vector2(1.1f, 1) : defaultScale; } // Unregister all event callbacks. void OnDisable() { cSharpLabel.UnregisterCallback<PointerOverEvent>(OnPointerOver); cSharpLabel.UnregisterCallback<PointerOutEvent>(OnPointerOut); } }
In Unity, select Window > UI Toolkit > Transition Example.
Hover over the first label. The label rotates and increases in size over three seconds.
Did you find this page useful? Please give it a rating:
Thanks for rating this page!
What kind of problem would you like to report?
Thanks for letting us know! This page has been marked for review based on your feedback.
If you have time, you can provide more information to help us fix the problem faster.
Provide more information
You've told us this page needs code samples. If you'd like to help us further, you could provide a code sample, or tell us about what kind of code sample you'd like to see:
You've told us there are code samples on this page which don't work. If you know how to fix it, or have something better we could use instead, please let us know:
You've told us there is information missing from this page. Please tell us more about what's missing:
You've told us there is incorrect information on this page. If you know what we should change to make it correct, please tell us:
You've told us this page has unclear or confusing information. Please tell us more about what you found unclear or confusing, or let us know how we could make it clearer:
You've told us there is a spelling or grammar error on this page. Please tell us what's wrong:
You've told us this page has a problem. Please tell us more about what's wrong:
Thank you for helping to make the Unity documentation better!
Your feedback has been submitted as a ticket for our documentation team to review.
We are not able to reply to every ticket submitted.
When you visit any website, it may store or retrieve information on your browser, mostly in the form of cookies. This information might be about you, your preferences or your device and is mostly used to make the site work as you expect it to. The information does not usually directly identify you, but it can give you a more personalized web experience. Because we respect your right to privacy, you can choose not to allow some types of cookies. Click on the different category headings to find out more and change our default settings. However, blocking some types of cookies may impact your experience of the site and the services we are able to offer.
More information
These cookies enable the website to provide enhanced functionality and personalisation. They may be set by us or by third party providers whose services we have added to our pages. If you do not allow these cookies then some or all of these services may not function properly.
These cookies allow us to count visits and traffic sources so we can measure and improve the performance of our site. They help us to know which pages are the most and least popular and see how visitors move around the site. All information these cookies collect is aggregated and therefore anonymous. If you do not allow these cookies we will not know when you have visited our site, and will not be able to monitor its performance.
These cookies may be set through our site by our advertising partners. They may be used by those companies to build a profile of your interests and show you relevant adverts on other sites. They do not store directly personal information, but are based on uniquely identifying your browser and internet device. If you do not allow these cookies, you will experience less targeted advertising. Some 3rd party video providers do not allow video views without targeting cookies. If you are experiencing difficulty viewing a video, you will need to set your cookie preferences for targeting to yes if you wish to view videos from these providers. Unity does not control this.
These cookies are necessary for the website to function and cannot be switched off in our systems. They are usually only set in response to actions made by you which amount to a request for services, such as setting your privacy preferences, logging in or filling in forms. You can set your browser to block or alert you about these cookies, but some parts of the site will not then work. These cookies do not store any personally identifiable information.