Get started with UI Toolkit

Want to create your first UI(User Interface) Allows a user to interact with your application. Unity currently supports three UI systems. More info
See in Glossary with UI Toolkit? Use this basic UI Toolkit workflow example to get started.

Note: For demonstration purpose, this guide describes how to add UI controls for the Editor UI. However, the instructions on adding UI controls to a UI Document also apply to runtime UI. For more information, see Get started with runtime UI.

If you perform a specific task often, you can use UI Toolkit to create a dedicated UI for it. For example you can create a custom Editor window. The example demonstrates how to create a custom Editor window and add UI controls into your custom Editor window with UI Builder, UXML, and C# script.

You can find the completed files that this example creates in this GitHub repository.

Create a custom Editor window

1. Create a project in Unity Editor with any template.
2. In the Project window, right-click in the Assets folder, and then select Create > UI Toolkit > Editor Window.
3. In UI Toolkit Editor Window Creator, enter MyCustomEditor.
4. Clear the USS checkbox.
5. Click Confirm.

This creates a custom Editor window with two labels. You can open the Editor window from the menu (Window > UI Toolkit > MyCustomEditor). You can find the source files for it in the Assets/Editor folder.

Add UI controls to the window

You can add UI controls into your window in the following ways:

• Use the UI Builder to visually add the UI controls
• Use an XML-like text file (UXML) to add the UI controls
• Use C# script to add the UI controls

You can use any of these methods individually, or combine. The following examples create three sets of labels, buttons, and toggles with a combination of these methods.

Use UI Builder to add UI controls

To visually add UI controls to your window, use UI Builder. The following steps add a button and a toggle into your custom Editor window in addition to the default label.

1. In the Editor folder, double-click MyCustomEditor.uxml to open the UI Builder.
2. In the UI Builder, drag Button and Toggle from Library > Controls into the Hierarchy or the window preview in the Viewport.
3. In the Hierarchy window, select Label.
4. In the InspectorA Unity window that displays information about the currently selected GameObject, asset or project settings, allowing you to inspect and edit the values. More info
   See in Glossary window, change the default text to These controls were created in UI Builder in the Text field.
5. In the Hierarchy window, select Button.
6. In the Inspector window, enter This is button1 in the Text field.
7. Enter button1 in the Name field.
8. In the Hierarchy window, select Toggle.
9. In the Inspector window, enter Number? in the Label field.
10. Enter toggle1 in the Name field.
11. Save and close the UI Builder window.
12. Close your custom Editor window if you haven’t done so.
13. Select Window > UI Toolkit > MyCustomEditor to re-open your custom Editor window to see the button and the toggle you just added.

Use UXML to add UI controls

If you prefer to define your UI in a text file, you can edit the UXML to add the UI controls. The following steps add another set of label, button, and toggle into your window.

1. In the Editor folder, click Assets > Create > UI Toolkit > UI Document to create a UXML file called MyCustomEditor_UXML.uxml.

2. Click the arrow on MyCustomEditor_UXML.uxml in the Project windowA window that shows the contents of your Assets folder (Project tab) More info
   See in Glossary.

3. Double-click inlineStyle to open MyCustomEditor_UXML.uxml in a text editor.

4. Replace the contents of MyCustomEditor_UXML.uxml with the following:

   <?xml version="1.0" encoding="utf-8"?>
   <engine:UXML
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:engine="UnityEngine.UIElements"
       xmlns:editor="UnityEditor.UIElements"
       xsi:noNamespaceSchemaLocation="../../UIElementsSchema/UIElements.xsd"
   >
       <engine:Label text="These controls were created with UXML." />
       <engine:Button text="This is button2" name="button2"/>
       <engine:Toggle label="Number?" name="toggle2"/>
   </engine:UXML>
   

5. Open MyCustomEditor.cs.

6. Add a private VisualTreeAsset field called m_UXMLTree to the MyCustomEditor class. Put the attribute [SerializeField] above it:

   [SerializeField]
   private VisualTreeAsset m_UXMLTree;
   

7. Add the following code to the end of CreateGUI().

   root.Add(m_UXMLTree.Instantiate());
   

8. In the Project window, select MyCustomEditor.cs.

9. Drag MyCustomEditor_UXML.uxml from the Project window into the UXML Tree field in the Inspector. This assigns your UXML to the visual tree.

10. Select Window > UI Toolkit > MyCustomEditor. This opens your custom Editor window with three labels, two buttons, and two toggles.

Use C# script to add UI controls

If you prefer coding, you can add UI Controls to your window with a C# script. The following steps add another set of label, button, and toggle into your window.

1. Open MyCustomEditor.cs.

2. Unity uses UnityEngine.UIElements for basic UI controls like label, button, and toggle. To work with UI controls, you must add the following declaration if it’s not already present.

   using UnityEngine.UIElements;
   

3. Change the text of the existing label from "Hello World! From C#" to "These controls were created using C# code.".

4. The EditorWindow class has a property called rootVisualElement. To add the UI controls to your window, first instantiate the element class with some attributes, and then use the Add methods of the rootVisualElement.

   Your finished CreateGUI() method should look like the following:

   public void CreateGUI()
   {
       // Each editor window contains a root VisualElement object
       VisualElement root = rootVisualElement;
   
       // VisualElements objects can contain other VisualElements following a tree hierarchy.
       Label label = new Label("These controls were created using C# code.");
       root.Add(label);
   
       Button button = new Button();
       button.name = "button3";
       button.text = "This is button3.";
       root.Add(button);
   
       Toggle toggle = new Toggle();
       toggle.name = "toggle3";
       toggle.label = "Number?";
       root.Add(toggle);
   
       // Import UXML
       var visualTree = AssetDatabase.LoadAssetAtPath<VisualTreeAsset>("Assets/Editor/MyCustomEditor.uxml");
       VisualElement labelFromUXML = visualTree.Instantiate();
       root.Add(labelFromUXML);
   }
   

5. Close your custom Editor window if you haven’t done so.

6. Select Window > UI Toolkit > MyCustomEditor to re-open your custom Editor window to see three labels, three buttons, and three toggles.

Define the behavior of your UI controls

You can set up event handlers for your UI controls so that when you click the button, and select or clear the toggle, your UI controls perform some tasks.

In this example, set up event handlers that:

• When a button is clicked, the Editor Console displays a message.
• When a toggle is selected, the Console shows how many times the buttons have been clicked.

Your finished MyCustomEditor.cs looks like the following:

using UnityEditor;
using UnityEngine;
using UnityEngine.UIElements;

public class MyCustomEditor : EditorWindow
{
    [MenuItem("Window/UI Toolkit/MyCustomEditor")]
    public static void ShowExample()
    {
        MyCustomEditor wnd = GetWindow<MyCustomEditor>();
        wnd.titleContent = new GUIContent("MyCustomEditor");
    }

    [SerializeField]
    private VisualTreeAsset m_UXMLTree;

    private int m_ClickCount = 0;

    private const string m_ButtonPrefix = "button";

    public void CreateGUI()
    {
        // Each editor window contains a root VisualElement object
        VisualElement root = rootVisualElement;

        // VisualElements objects can contain other VisualElement following a tree hierarchy.
        Label label = new Label("These controls were created using C# code.");
        root.Add(label);

        Button button = new Button();
        button.name = "button3";
        button.text = "This is button3.";
        root.Add(button);

        Toggle toggle = new Toggle();
        toggle.name = "toggle3";
        toggle.label = "Number?";
        root.Add(toggle);

        // Import UXML
        var visualTree = AssetDatabase.LoadAssetAtPath<VisualTreeAsset>("Assets/Editor/MyCustomEditor.uxml");
        VisualElement labelFromUXML = visualTree.Instantiate();
        root.Add(labelFromUXML);

        root.Add(m_UXMLTree.Instantiate());

        //Call the event handler
        SetupButtonHandler();
    }

    //Functions as the event handlers for your button click and number counts 
    private void SetupButtonHandler()
    {
        VisualElement root = rootVisualElement;

        var buttons = root.Query<Button>();
        buttons.ForEach(RegisterHandler);
    }

    private void RegisterHandler(Button button)
    {
        button.RegisterCallback<ClickEvent>(PrintClickMessage);
    }

    private void PrintClickMessage(ClickEvent evt)
    {
        VisualElement root = rootVisualElement;

        ++m_ClickCount;

        //Because of the names we gave the buttons and toggles, we can use the
        //button name to find the toggle name.
        Button button = evt.currentTarget as Button;
        string buttonNumber = button.name.Substring(m_ButtonPrefix.Length);
        string toggleName = "toggle" + buttonNumber;
        Toggle toggle = root.Q<Toggle>(toggleName);

        Debug.Log("Button was clicked!" +
            (toggle.value ? " Count: " + m_ClickCount : ""));
    }
}

To try the example, select Window > UI Toolkit > MyCustomEditor.

Additional resources

• UXML
• Visual TreeAn object graph, made of lightweight nodes, that holds all the elements in a window or panel. It defines every UI you build with the UI Toolkit.
  See in Glossary
• Label
• Button
• ToggleA checkbox that allows the user to switch an option on or off. More info
  See in Glossary
• Create a custom Editor window