public IDragAndDropContainer GetContainer()
{
IDragAndDropContainer container = null;
Transform par = transform.parent;
while (container == null && par != null)
{
container = par.GetComponent <IDragAndDropContainer>();
par = par.parent;
}
if (container != null)
{
cachedContainer = container;
}
else
{
container = cachedContainer;
}
return(container);
}
void Update()
{
// on mouse down, start dragging if we find a draggable
if (Input.GetMouseButtonDown(0))
{
objectToDrag = GetDraggableTransformUnderMouse();
// check with the container to see if we can drag objects
if (objectToDrag != null)
{
IDragAndDropContainer containerDrag = objectToDrag.GetContainer();
if (containerDrag != null && containerDrag.CanDrag(objectToDrag) == false)
{
objectToDrag = null;
}
}
if (objectToDrag != null)
{
dragging = true;
// do this so the dragged object appears on top of other sibling containers
//objectToDrag.transform.parent.SetAsLastSibling();
originalPosition = objectToDrag.transform.position;
originalParent = objectToDrag.transform.parent;
Transform parentCanvas = objectToDrag.transform.parent;
while (parentCanvas != null && parentCanvas.GetComponent <Canvas>() == null)
{
parentCanvas = parentCanvas.parent;
}
objectToDrag.transform.parent = parentCanvas;
parentCanvas.SetAsLastSibling();
// make the dragged object appear over all other objects in the container
objectToDrag.transform.SetAsLastSibling();
// make the object being dragged transparent to raycasts
objectToDragImage = objectToDrag.GetComponent <Image>();
objectToDragImage.raycastTarget = false;
}
}
if (dragging)
{
objectToDrag.transform.position = Input.mousePosition;
}
// on mouse up, try to complete the drag and drop
if (Input.GetMouseButtonUp(0))
{
if (objectToDrag != null)
{
IDraggable objectToReplace = GetDraggableTransformUnderMouse();
// find the container we're dropping in to and from
IDragAndDropContainer containerReplace = null;
IDragAndDropContainer containerDrag = objectToDrag.GetContainer();
if (objectToReplace)
{
containerReplace = objectToReplace.GetContainer();
// if there is a container and we can't drop into it for game logic reasons, cancel the drag
if (containerReplace != null)
{
if (containerReplace.CanDrop(objectToDrag, objectToReplace) == false)
{
objectToReplace = null;
}
}
// check the other way too, since the drag and drop is a swap
if (containerDrag != null)
{
if (containerDrag.CanDrop(objectToReplace, objectToDrag) == false)
{
objectToReplace = null;
}
}
}
if (objectToReplace != null)
{
// store the indexes of where these objects came from to pass through, they may get changed in Drop() calls
int dragIndex = objectToDrag.index;
int replaceIndex = objectToReplace.index;
IDraggable replacement = Instantiate(objectToReplace);
IDraggable current = Instantiate(objectToDrag);
// game logic - let both containers know about the update
if (containerReplace != null)
{
containerReplace.Drop(current, objectToReplace, replaceIndex, containerReplace != containerDrag);
}
if (containerDrag != null)
{
containerDrag.Drop(replacement, objectToDrag, dragIndex, true);
}
if (objectToDrag.GetContainer().DoesSwap())
{
// swap positions
objectToDrag.transform.position = objectToReplace.transform.position;
objectToReplace.transform.position = originalPosition;
// swap parents
objectToDrag.transform.parent = objectToReplace.transform.parent;
objectToReplace.transform.parent = originalParent;
}
else
{
// return to point of origin and nothing happens
objectToDrag.transform.position = originalPosition;
objectToDrag.transform.parent = originalParent;
}
}
else
{
// return to point of origin and nothing happens
objectToDrag.transform.position = originalPosition;
objectToDrag.transform.parent = originalParent;
}
objectToDragImage.raycastTarget = true;
objectToDrag = null;
}
dragging = false;
}
}
