Version: 2021.3+
This example demonstrates how to create a list view runtime UI.
This example creates a simple character selection screen. When you click the name of a character from a list on the left, the detail of the character appears on the right.
You can find the completed files that this example creates in this GitHub repository.
This guide is for developers familiar with Unity Editor, UI Toolkit, and C# scripting. You are recommended to have a basic understanding of the following:
Create the main view UI Document and a USS file to style the visual elements. Add two visual elements as containers in the UI Document: one that contains the list of character names and another that contains the selected character’s details.
Create a project in Unity with any template.
In the Project window, create a folder named UI
to store all the UI Document and Style Sheet files.
In the UI
folder, create a UI Document named MainView.uxml
with the following content:
<ui:UXML xmlns:ui="UnityEngine.UIElements" xmlns:uie="UnityEditor.UIElements" editor-extension-mode="False">
<Style src="MainView.uss" />
<ui:VisualElement name="background">
<ui:VisualElement name="main-container">
<ui:ListView focusable="true" name="character-list" />
<ui:VisualElement name="right-container">
<ui:VisualElement name="details-container">
<ui:VisualElement name="details">
<ui:VisualElement name="character-portrait" />
</ui:VisualElement>
<ui:Label text="Label" name="character-name" />
<ui:Label text="Label" display-tooltip-when-elided="true" name="character-class" />
</ui:VisualElement>
<ui:Button text="Select Character" display-tooltip-when-elided="true" name="select-char-button" />
</ui:VisualElement>
</ui:VisualElement>
</ui:VisualElement>
</ui:UXML>
In the UI
folder, create a USS style sheet named MainView.uss
with the following content:
#background {
flex-grow: 1;
align-items: center;
justify-content: center;
background-color: rgb(115, 37, 38);
}
#main-container {
flex-direction: row;
height: 350px;
}
#character-list {
width: 230px;
border-color: rgb(49, 26, 17);
border-width: 4px;
background-color: rgb(110, 57, 37);
border-radius: 15px;
margin-right: 6px;
}
#character-name {
-unity-font-style: bold;
font-size: 18px;
}
#CharacterClass {
margin-top: 2px;
margin-bottom: 8px;
padding-top: 0;
padding-bottom: 0;
}
#select-char-button {
width: 150px;
border-color: rgb(49, 26, 17);
background-color: rgb(255, 133, 84);
border-width: 2px;
}
#right-container{
justify-content: space-between;
align-items: flex-end;
}
#details-container{
align-items: center;
background-color: rgb(170, 89, 57);
border-width: 4px;
border-color: rgb(49, 26, 17);
border-radius: 15px;
width: 252px;
justify-content: center;
padding: 8px;
height: 163px;
}
#details{
border-color: rgb(49, 26, 17);
border-width: 2px;
height: 120px;
width: 120px;
border-radius: 13px;
padding: 4px;
background-color: rgb(255, 133, 84);
}
#character-portrait{
flex-grow: 1;
-unity-background-scale-mode: scale-to-fit;
}
Create a UI Document and a Style Sheet for the individual entries in the list. The character list entry consists of a colored background frame and the character’s name.
In the UI
folder, create a UI Document named ListEntry.uxml
with the following content:
<ui:UXML xmlns:ui="UnityEngine.UIElements" xmlns:uie="UnityEditor.UIElements" editor-extension-mode="False">
<Style src="ListEntry.uss" />
<ui:VisualElement name="list-entry">
<ui:Label text="Label" display-tooltip-when-elided="true" name="character-name" />
</ui:VisualElement>
</ui:UXML>
In the UI
folder, create a Style Sheet file named ListEntry.uss
with the following content:
#list-entry {
height: 41px;
align-items: flex-start;
justify-content: center;
padding-left: 10px;
background-color: rgb(170, 89, 57);
border-color: rgb(49, 26, 17);
border-width: 2px;
border-radius: 15px;
}
#character-name {
-unity-font-style: bold;
font-size: 18px;
color: rgb(49, 26, 17);
}
Create sample data to fill the character list in the UI. For the character list, create a class that holds a character name, class, and a portrait image.
In the Asset folder, create a folder named Scripts
to store your C# scripts.
In the Scripts
folder, create a C# script named CharacterData.cs
with the following content:
using UnityEngine;
public enum ECharacterClass
{
Knight, Ranger, Wizard
}
[CreateAssetMenu] //This adds an entry to the **Create** menu
public class CharacterData : ScriptableObject
{
public string m_CharacterName;
public ECharacterClass m_Class;
public Sprite m_PortraitImage;
}
This creates a Character Data item in the Assets > Create menu.
In the Assets folder, create a folder named Resources
.
In the Resources
folder, create a folder named Characters
to store all your sample character data.
In the Characters
folder, right-click and select Create > Character Data to create an instance of the ScriptableObject
.
Create more CharacterData
instances and fill them with placeholder data.
Create a UIDocument GameObject in the SampleScene and add the UI Document as the source asset.
Create two C# scripts with the following classes:
CharacterListEntryController
class to display the data of a character instance in the UI of the list entry. It needs to access the label for the character name and set it to display the name of the given character instance.CharacterListController
class for the character list in the main view, and a MonoBehaviour
script that instantiates and assigns it to the visual tree.Note: The CharacterListEntryController
class isn’t a MonoBehaviour
. Since the visual elements in UI Toolkit aren’t GameObjects, you can’t attach components to them. Instead, you attach the class to the userData
property in the CharacterListController
class.
In the Scripts
folder, create a C# script named CharacterListEntryController.cs
with the following contents:
using UnityEngine.UIElements;
public class CharacterListEntryController
{
Label m_NameLabel;
//This function retrieves a reference to the
//character name label inside the UI element.
public void SetVisualElement(VisualElement visualElement)
{
m_NameLabel = visualElement.Q<Label>("character-name");
}
//This function receives the character whose name this list
//element displays. Since the elements listed
//in a `ListView` are pooled and reused, it's necessary to
//have a `Set` function to change which character's data to display.
public void SetCharacterData(CharacterData characterData)
{
m_NameLabel.text = characterData.m_CharacterName;
}
}
In the Scripts
folder, create a C# script named CharacterListController.cs
with the following content:
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UIElements;
public class CharacterListController
{
// UXML template for list entries
VisualTreeAsset m_ListEntryTemplate;
// UI element references
ListView m_CharacterList;
Label m_CharClassLabel;
Label m_CharNameLabel;
VisualElement m_CharPortrait;
public void InitializeCharacterList(VisualElement root, VisualTreeAsset listElementTemplate)
{
EnumerateAllCharacters();
// Store a reference to the template for the list entries
m_ListEntryTemplate = listElementTemplate;
// Store a reference to the character list element
m_CharacterList = root.Q<ListView>("character-list");
// Store references to the selected character info elements
m_CharClassLabel = root.Q<Label>("character-class");
m_CharNameLabel = root.Q<Label>("character-name");
m_CharPortrait = root.Q<VisualElement>("character-portrait");
FillCharacterList();
// Register to get a callback when an item is selected
m_CharacterList.onSelectionChange += OnCharacterSelected;
}
List<CharacterData> m_AllCharacters;
void EnumerateAllCharacters()
{
m_AllCharacters = new List<CharacterData>();
m_AllCharacters.AddRange(Resources.LoadAll<CharacterData>("Characters"));
}
void FillCharacterList()
{
// Set up a make item function for a list entry
m_CharacterList.makeItem = () =>
{
// Instantiate the UXML template for the entry
var newListEntry = m_ListEntryTemplate.Instantiate();
// Instantiate a controller for the data
var newListEntryLogic = new CharacterListEntryController();
// Assign the controller script to the visual element
newListEntry.userData = newListEntryLogic;
// Initialize the controller script
newListEntryLogic.SetVisualElement(newListEntry);
// Return the root of the instantiated visual tree
return newListEntry;
};
// Set up bind function for a specific list entry
m_CharacterList.bindItem = (item, index) =>
{
(item.userData as CharacterListEntryController).SetCharacterData(m_AllCharacters[index]);
};
// Set a fixed item height
m_CharacterList.fixedItemHeight = 45;
// Set the actual item's source list/array
m_CharacterList.itemsSource = m_AllCharacters;
}
void OnCharacterSelected(IEnumerable<object> selectedItems)
{
// Get the currently selected item directly from the ListView
var selectedCharacter = m_CharacterList.selectedItem as CharacterData;
// Handle none-selection (Escape to deselect everything)
if (selectedCharacter == null)
{
// Clear
m_CharClassLabel.text = "";
m_CharNameLabel.text = "";
m_CharPortrait.style.backgroundImage = null;
return;
}
// Fill in character details
m_CharClassLabel.text = selectedCharacter.m_Class.ToString();
m_CharNameLabel.text = selectedCharacter.m_CharacterName;
m_CharPortrait.style.backgroundImage = new StyleBackground(selectedCharacter.m_PortraitImage);
}
}
The CharacterListController
isn’t a MonoBehaviour
, so it must be attached to the visual tree. Create a MonoBehaviour
script that you can attach to the same GameObject as the UIDocument. It instantiates the CharacterListController
and attaches it to the Visual Tree.
In the Scripts
folder, create a C# script named MainView.cs
with the following content:
using UnityEngine;
using UnityEngine.UIElements;
public class MainView : MonoBehaviour
{
[SerializeField]
VisualTreeAsset m_ListEntryTemplate;
void OnEnable()
{
// The UXML is already instantiated by the UIDocument component
var uiDocument = GetComponent<UIDocument>();
// Initialize the character list controller
var characterListController = new CharacterListController();
characterListController.InitializeCharacterList(uiDocument.rootVisualElement, m_ListEntryTemplate);
}
}
In the SampleScene, select UI Toolkit Runtime UI.
Drag MainView.cs
to Add Component in the Inspector window.
Drag ListEntry.uxml to the ListEntry Template field.
Enter Play mode to see your UI displayed in the game view.