【Unity】UI ToolkitのDragAndDropサンプル

UIToolkit_DragAndDropTest.cs

using UnityEngine;
using UnityEngine.UIElements;

/// <summary>
/// DragAndDrop Sample
/// </summary>
[RequireComponent(typeof(UIDocument))]
public class UIToolkit_DragAndDropTest : MonoBehaviour
{
    private Vector2 _dragOffset;

    void OnEnable()
    {
        var document = GetComponent<UIDocument>();
        var rootVisualElement = document.rootVisualElement;

        var dragTarget = rootVisualElement.Q<VisualElement>("dragTarget");
        dragTarget.RegisterCallback<PointerDownEvent>(OnPointerDown);
        dragTarget.RegisterCallback<PointerMoveEvent>(OnPointerMove);
        dragTarget.RegisterCallback<PointerUpEvent>(OnPointerUp);
    }


    private void OnPointerDown(PointerDownEvent evt)
    {
        evt.target.CapturePointer(evt.pointerId);
        var draggedTarget = (VisualElement) evt.target;
        _dragOffset = new Vector2(draggedTarget.resolvedStyle.left, draggedTarget.resolvedStyle.top)
                      - new Vector2(evt.position.x, evt.position.y);
    }

    private void OnPointerMove(PointerMoveEvent evt)
    {
        if (evt.target.HasPointerCapture(evt.pointerId))
        {
            var pos = new Vector2(evt.position.x, evt.position.y) + _dragOffset;
            var draggedTarget = (VisualElement) evt.target;
            draggedTarget.style.left = pos.x;
            draggedTarget.style.top = pos.y;
        }
    }

    private void OnPointerUp(PointerUpEvent evt)
    {
        if (evt.target.HasPointerCapture(evt.pointerId))
        {
            evt.target.ReleasePointer(evt.pointerId);
        }
    }
}

UIToolkit_DragAndDropTest.uxml

<ui:UXML xmlns:ui="UnityEngine.UIElements" editor-extension-mode="False">
    <ui:VisualElement name="container" style="height: 100%; width: 100%; background-color: rgb(255, 255, 186);">
        <ui:VisualElement name="dragTarget" style="width: 119px; height: 106px; background-color: rgba(255, 175, 28, 255);" />
    </ui:VisualElement>
</ui:UXML>