Unity编辑器 - DragAndDrop拖拽控件

Unity编辑器 - DragAndDrop拖拽控件

Unity编辑器的拖拽（DragAndDrop）在网上能找到的资料少，自己稍微研究了一下，写了个相对完整的案例，效果如下

代码：

object dragData = "dragData";
Vector2 offset;
Color col = new Color(1, 0, 0, 0.6f);
Rect rect1 = new Rect(20, 10, 100, 20);
Rect rect2 = new Rect(20, 60, 100, 20);
Rect drect;
bool isDraging;
int cid;

private void OnGUI() {
    GUI.Box(rect1, "rect1");
    GUI.Box(rect2, "rect2");

    Event e = Event.current;
    cid = GUIUtility.GetControlID(FocusType.Passive);
    switch (e.GetTypeForControl(cid)) {
        case EventType.MouseDown:
            if (rect1.Contains(e.mousePosition))
                GUIUtility.hotControl = cid;
            break;
        case EventType.MouseUp:
            if (GUIUtility.hotControl == cid)
                GUIUtility.hotControl = 0;
            break;
        case EventType.MouseDrag:
            Debug.Log("MouseDrag");
            if (GUIUtility.hotControl == cid && rect1.Contains(e.mousePosition)) {
                DragAndDrop.PrepareStartDrag();
                //DragAndDrop.objectReferences = new Object[] { };
                DragAndDrop.SetGenericData("dragflag", dragData);
                DragAndDrop.StartDrag("dragtitle");
                offset = e.mousePosition - rect1.position;
                drect = rect1;
                isDraging = true;
                e.Use();
            }
            break;
        case EventType.DragUpdated:
            Debug.Log("DragUpdated");
            drect.position = e.mousePosition - offset;
            if (rect2.Contains(e.mousePosition)) {
                DragAndDrop.visualMode = DragAndDropVisualMode.Generic;
                drect = rect2;
            }
            e.Use();
            break;
        case EventType.DragPerform:
            Debug.Log("DragPerform");
            DragAndDrop.AcceptDrag();
            Debug.Log("DragPerform : " + DragAndDrop.GetGenericData("dragflag"));
            e.Use();
            break;
        case EventType.DragExited:
            Debug.Log("DragExited");
            isDraging = false;
            if (GUIUtility.hotControl == cid)
                GUIUtility.hotControl = 0;
            e.Use();
            break;
    }

    if (isDraging) {
        EditorGUI.DrawRect(drect, col);
    }
}

事件调用顺序