public void DragDropArea <T>(
string label, int labelSize, GUIStyle style,
Predicate <UnityObject[]> canSetVisualModeToCopy, MouseCursor cursor,
Action <T> onDrop, Action onMouseUp,
float preSpace, float postSpace = 0f, float height = 0f) where T : UnityEngine.Object
{
using (Horizontal())
{
Space(preSpace);
Box(label, style);
var dropArea = LastRect;
{
// cache the current event
Event currentEvent = Event.current;
// if our mouse isn't contained within that box area, exit out
if (dropArea.Contains(currentEvent.mousePosition))
{
GUIHelper.AddCursorRect(dropArea, cursor);
if (onMouseUp != null && currentEvent.type == EventType.MouseUp)
{
onMouseUp();
}
if (onDrop != null)
{
if (currentEvent.type == EventType.DragUpdated ||
currentEvent.type == EventType.DragPerform)
{
// set the visual mode to copy
DragAndDrop.visualMode = canSetVisualModeToCopy(DragAndDrop.objectReferences) ?
DragAndDropVisualMode.Copy : DragAndDropVisualMode.Rejected;
// if we dropped something
if (currentEvent.type == EventType.DragPerform)
{
// register that this drag-drop event has been handled by this control
DragAndDrop.AcceptDrag();
// loop over the dropped items and notify onDrop of each object
for (int i = 0; i < DragAndDrop.objectReferences.Length; i++)
{
onDrop(DragAndDrop.objectReferences[i] as T);
}
}
// since we've used the DragPerform event, we'll mark it as used
// (its type will change to EventType.Used)
// so that other Controls ignore it
Event.current.Use();
}
}
}
}
Space(postSpace);
}
}