public static bool TryAddItem(DragDropItem item, DragDropTarget target, bool sendCallback = true)
{
if (item == null || target == null)
{
return(false);
}
if (!(item.isActiveAndEnabled && target.isActiveAndEnabled))
{
return(false);
}
if (item.attachedTarget != null)
{
return(false);
}
if (!IsChannelMatch(target, item))
{
return(false);
}
DragDropEventData eventData = new DragDropEventData(!sendCallback);
eventData.Reset();
eventData.target = target;
eventData.item = item;
target.OnItemAttach(eventData);
item.OnItemAttach(eventData);
return(true);
}
public static bool TryAddItem(DragDropItem item, DragDropTarget target)
{
if (item.attachedTarget != null)
{
return(false);
}
if (!IsChannelMatch(target, item))
{
return(false);
}
if (target.currentItemCount >= target.maxItemCount)
{
return(false);
}
DragDropEventData eventData = new DragDropEventData();
eventData.Reset();
eventData.external = true;
eventData.target = target;
eventData.item = item;
target.OnItemEnter(eventData);
item.OnItemEnter(eventData);
target.OnItemAttach(eventData);
item.OnItemAttach(eventData);
return(true);
}
public void OnPointerUp(PointerEventData eventData)
{
if (DragDropEventData.current.eligibleForClick)
{
OnClick(DragDropEventData.current);
}
if (!HandlingDragDropEvent())
{
DragDropEventData.current.Reset();
return;
}
if (DragDropEventData.current.valid)
{
DragDropItem replacedItem = null;
if (DragDropEventData.current.target.CheckCanAttachItem(DragDropEventData.current, out replacedItem))
{
if (replacedItem)
{
// 旧item 离开
DragDropEventData.current.isReplaced = true;
DragDropEventData.current.item = replacedItem;
DragDropEventData.current.target.OnItemDetach(DragDropEventData.current);
replacedItem.OnItemDetach(DragDropEventData.current);
// 新item 附着
DragDropEventData.current.isReplaced = false;
DragDropEventData.current.item = this;
DragDropEventData.current.target.OnItemAttach(DragDropEventData.current);
OnItemAttach(DragDropEventData.current);
// 旧item 附着到新item原来的target 完成交换
DragDropEventData.current.isReplaced = true;
DragDropEventData.current.item = replacedItem;
DragDropEventData.current.target = lastTarget;
if (DragDropEventData.current.valid)
{
lastTarget.OnItemAttach(DragDropEventData.current);
replacedItem.OnItemAttach(DragDropEventData.current);
}
else
{
replacedItem.attachedTarget = null;
replacedItem.OnSetFree(DragDropEventData.current);
}
}
else
{
DragDropEventData.current.target.OnItemAttach(DragDropEventData.current);
OnItemAttach(DragDropEventData.current);
}
}
else
{
DragDropEventData.current.target.OnItemExit(DragDropEventData.current);
OnItemExit(DragDropEventData.current);
}
}
else
{
OnSetFree(DragDropEventData.current);
}
DragDropEventData.current.Reset();
}
