// This method is called from TreeView and handles:
// - Where the dragged items are dropped (above, below or upon)
// - Auto expansion of collapsed items when hovering over them
// - Setting up the render markers for drop location (horizontal lines)
// 'targetItem' is null when not hovering over any target Item, if so the rest of the arguments are invalid
public virtual bool DragElement(TreeViewItem targetItem, Rect targetItemRect, int row)
{
bool perform = Event.current.type == EventType.DragPerform;
// Are we dragging outside any items
if (targetItem == null)
{
// If so clear any drop markers
if (m_DropData != null)
{
m_DropData.dropTargetControlID = 0;
m_DropData.rowMarkerControlID = 0;
}
// And let client decide what happens when dragging outside items
DragAndDrop.visualMode = DoDrag(null, null, perform, DropPosition.Below);
if (DragAndDrop.visualMode != DragAndDropVisualMode.None && perform)
{
FinalizeDragPerformed(true);
}
return(false);
}
DropPosition dropPosition;
if (!TryGetDropPosition(targetItem, targetItemRect, row, out dropPosition))
{
return(false);
}
TreeViewItem parentItem = null;
switch (dropPosition)
{
case DropPosition.Upon:
{
// Client must decide what happens when dropping upon: e.g: insert last or first in child list
parentItem = targetItem;
}
break;
case DropPosition.Below:
{
// When hovering between an expanded parent and its first child then make sure we change state to match that
if (m_TreeView.data.IsExpanded(targetItem) && targetItem.hasChildren)
{
parentItem = targetItem;
targetItem = targetItem.children[0];
dropPosition = DropPosition.Above;
}
else
{
// Drop as next sibling to target
parentItem = targetItem.parent;
}
}
break;
case DropPosition.Above:
{
parentItem = targetItem.parent;
}
break;
default:
Assert.IsTrue(false, Constants.UnhandledEnum);
break;
}
DragAndDropVisualMode mode = DragAndDropVisualMode.None;
if (perform)
{
// Try Drop on top of element
if (dropPosition == DropPosition.Upon)
{
mode = DoDrag(targetItem, targetItem, true, dropPosition);
}
// Fall back to dropping on parent (drop between elements)
if (mode == DragAndDropVisualMode.None && parentItem != null)
{
mode = DoDrag(parentItem, targetItem, true, dropPosition);
}
// Finalize drop
if (mode != DragAndDropVisualMode.None)
{
FinalizeDragPerformed(false);
}
else
{
DragCleanup(true);
m_TreeView.NotifyListenersThatDragEnded(null, false);
}
}
else // DragUpdate
{
if (m_DropData == null)
{
m_DropData = new DropData();
}
m_DropData.dropTargetControlID = 0;
m_DropData.rowMarkerControlID = 0;
int itemControlID = TreeViewController.GetItemControlID(targetItem);
HandleAutoExpansion(itemControlID, targetItem, targetItemRect);
// Try drop on top of element
if (dropPosition == DropPosition.Upon)
{
mode = DoDrag(targetItem, targetItem, false, dropPosition);
}
if (mode != DragAndDropVisualMode.None)
{
m_DropData.dropTargetControlID = itemControlID;
DragAndDrop.visualMode = mode;
}
// Fall back to dropping on parent (drop between elements)
else if (targetItem != null && parentItem != null)
{
mode = DoDrag(parentItem, targetItem, false, dropPosition);
if (mode != DragAndDropVisualMode.None)
{
drawRowMarkerAbove = dropPosition == DropPosition.Above;
m_DropData.rowMarkerControlID = itemControlID;
DragAndDrop.visualMode = mode;
}
}
}
Event.current.Use();
return(true);
}
// This method is called from TreeView and handles:
// - Where the dragged items are dropped (above, below or upon)
// - Auto expansion of collapsed items when hovering over them
// - Setting up the render markers for drop location (horizontal lines)
// 'targetItem' is null when not hovering over any target Item, if so the rest of the arguments are invalid
public virtual bool DragElement(TreeViewItem targetItem, Rect targetItemRect, int row)
{
bool perform = Event.current.type == EventType.DragPerform;
// Are we dragging outside any items
if (targetItem == null)
{
// If so clear any drop markers
if (m_DropData != null)
{
m_DropData.ClearPerEventState();
}
// And let client decide what happens when dragging outside items
DragAndDrop.visualMode = DoDrag(null, null, perform, DropPosition.Below);
if (DragAndDrop.visualMode != DragAndDropVisualMode.None && perform)
{
FinalizeDragPerformed(true);
}
return(false);
}
DropPosition dropPosition;
if (!TryGetDropPosition(targetItem, targetItemRect, row, out dropPosition))
{
return(false);
}
TreeViewItem parentItem = null;
TreeViewItem dropRelativeToItem = targetItem;
bool didChangeTargetToAncector = false;
DropPosition originalDropPosition = dropPosition;
switch (dropPosition)
{
case DropPosition.Upon:
// Parent change: Client must decide what happens when dropping upon: e.g: insert last or first in child list
parentItem = dropRelativeToItem;
break;
case DropPosition.Below:
case DropPosition.Above:
// Sibling change
if (getIndentLevelForMouseCursor != null)
{
int cursorDepth = getIndentLevelForMouseCursor();
HandleSiblingInsertionAtAvailableDepthsAndChangeTargetIfNeeded(ref dropRelativeToItem, row, ref dropPosition, cursorDepth, out didChangeTargetToAncector);
}
else
{
if (dropPosition == DropPosition.Below && m_TreeView.data.IsExpanded(dropRelativeToItem) && dropRelativeToItem.hasChildren)
{
// When hovering between an expanded parent and its first child then make sure we change state to match that
dropPosition = DropPosition.Above;
dropRelativeToItem = dropRelativeToItem.children[0];
}
}
parentItem = dropRelativeToItem.parent;
break;
default:
Debug.LogError("Unhandled enum. Report a bug.");
break;
}
if (perform)
{
DragAndDropVisualMode mode = DragAndDropVisualMode.None;
// Try Drop upon target item
if (dropPosition == DropPosition.Upon)
{
mode = DoDrag(dropRelativeToItem, dropRelativeToItem, true, dropPosition);
}
// Drop between items
if (mode == DragAndDropVisualMode.None && parentItem != null)
{
mode = DoDrag(parentItem, dropRelativeToItem, true, dropPosition);
}
// Finalize drop
if (mode != DragAndDropVisualMode.None)
{
FinalizeDragPerformed(false);
}
else
{
DragCleanup(true);
m_TreeView.NotifyListenersThatDragEnded(null, false);
}
}
else // DragUpdate
{
if (m_DropData == null)
{
m_DropData = new DropData();
}
m_DropData.ClearPerEventState();
// Try drop on top of items
if (dropPosition == DropPosition.Upon)
{
int itemControlID = TreeViewController.GetItemControlID(dropRelativeToItem);
HandleAutoExpansion(itemControlID, dropRelativeToItem, targetItemRect);
var mode = DoDrag(dropRelativeToItem, dropRelativeToItem, false, dropPosition);
if (mode != DragAndDropVisualMode.None)
{
m_DropData.dropTargetControlID = itemControlID;
DragAndDrop.visualMode = mode;
}
}
// Drop between items
else if (dropRelativeToItem != null && parentItem != null)
{
var mode = DoDrag(parentItem, dropRelativeToItem, false, dropPosition);
if (mode != DragAndDropVisualMode.None)
{
drawRowMarkerAbove = dropPosition == DropPosition.Above;
m_DropData.rowMarkerControlID = TreeViewController.GetItemControlID(dropRelativeToItem);
m_DropData.insertionMarkerYPosition = originalDropPosition == DropPosition.Above ? targetItemRect.y : targetItemRect.yMax;
m_DropData.insertRelativeToSibling = dropRelativeToItem;
if (didChangeTargetToAncector)
{
m_DropData.ancestorControlID = TreeViewController.GetItemControlID(dropRelativeToItem);
}
DragAndDrop.visualMode = mode;
}
}
}
Event.current.Use();
return(true);
}