To build UI(User Interface) Allows a user to interact with your application. Unity currently supports three UI systems. More info
See in Glossary from a UXML file, you must first load the file into a VisualTreeAsset, and then use the Instantiate() to instantiate without a parent, which creates a new TemplateContainer, or CloneTree(parent)) to clone inside a parent.
Once the UXML is instantiated, you can retrieve specific elements from the 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 with UQuery.
The following example creates a custom Editor window and loads a UXML file as its content:
using UnityEditor;
using UnityEngine;
using UnityEngine.UIElements;
using UnityEditor.UIElements;
public class MyWindow : EditorWindow {
[MenuItem ("Window/My Window")]
public static void ShowWindow () {
EditorWindow w = EditorWindow.GetWindow(typeof(MyWindow));
VisualTreeAsset uiAsset = AssetDatabase.LoadAssetAtPath<VisualTreeAsset>("Assets/MyWindow.uxml");
VisualElement ui = uiAsset.Instantiate();
w.rootVisualElement.Add(ui);
}
}