UI Systems Roadmap

We don't have a public roadmap to share at this time, but we do have (basic) support for drag and drop operations. It still requires a bit of manual work. The drag&drop events can be used together with the UnityEditor.DragAndDrop class to ease the work a little bit. See this example:

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using UnityEditor;
5. using UnityEngine.UIElements;
6. using UnityEditor.UIElements;
7.  
8. public class DragDrop : EditorWindow
9. {
10.     [MenuItem("Demo/Drag Drop")]
11.     public static void DoIt()
12.     {
13.         GetWindow<DragDrop>().Show();
14.     }
15.  
16.     void OnEnable()
17.     {
18.         var source = new VisualElement() {
19.             style = {
20.                 position = Position.Absolute,
21.                 left = 20, top = 20, width = 100, height = 100,
22.                 backgroundColor = Color.blue
23.             }
24.         };
25.         source.Add(new Label() { text = "Source", style = { color = Color.black } });
26.         source.RegisterCallback<MouseDownEvent>(OnSourceMouseDown);
27.         rootVisualElement.Add(source);
28.  
29.         var dropZone = new VisualElement() {
30.             style = {
31.                 position = Position.Absolute,
32.                 left = 200, top = 20, width = 100, height = 100,
33.                 backgroundColor = Color.green
34.             }
35.         };
36.         dropZone.Add(new Label() { text = "Drop Zone", style = { color = Color.black } });
37.         dropZone.RegisterCallback<DragEnterEvent>(OnDragEnter);
38.         dropZone.RegisterCallback<DragUpdatedEvent>(OnDragUpdated);
39.         dropZone.RegisterCallback<DragPerformEvent>(OnDragPerfom);
40.         rootVisualElement.Add(dropZone);
41.     }
42.  
43.     void UpdateDrag()
44.     {
45.         DragAndDrop.visualMode = DragAndDropVisualMode.Link;
46.     }
47.  
48.     void OnSourceMouseDown(MouseDownEvent e)
49.     {
50.         DragAndDrop.PrepareStartDrag();
51.         DragAndDrop.StartDrag("Dragging");
52.     }
53.  
54.     void OnDragEnter(DragEnterEvent e)
55.     {
56.         UpdateDrag();
57.     }
58.  
59.     void OnDragUpdated(DragUpdatedEvent e)
60.     {
61.         UpdateDrag();
62.     }
63.  
64.     void OnDragPerfom(DragPerformEvent e)
65.     {
66.         Debug.Log("Drag performed: " + e.target);
67.         DragAndDrop.AcceptDrag();
68.     }
69. }
70.