Our diagram sits next to a JTree, and we would like to be able to select an item or items from the JTree and drag them onto a Diagram Node.

Note that the items in the JTree are not JDiagram items, but would need to be converted to items which the Diagram Nodes do support/contain, however we do currently have functioning code to perform this conversion.

Is this theoretically possible? Do Diagram Nodes support classic drag and drop functionality? If not, might it be possible to use the clipboard functionality to 'simulate' drag and drop functionality?

All your examples show 'drop' onto the DiagramView and create a new DiagramNode.

What we actually want to do is 'drop' onto an existing DiagramNode (actually a CompositeNode) to add data to it. I can't find 'addTransferHandler()' on DiagramNode, so I assume this isn't directly supported.

Is it possible to, easily, detect which DiagramNode (if any) is in the position being 'dropped' on in the DiagramView, to enable us to make it look as if the 'drop' was onto the DiagramNode itself?

I've tried your suggestion but the call to

diagramView.getMousePosition(true) 

is returning Null.

The diagramView object seems to be okay as far as I can tell. If I look on its diagram object I can see the 3 composite nodes which are on the particular diagram I am testing with.

Any idea why getMousePosition(true) might be returning null? [Have also tried getMousePosition() and getMousePosition(false) but they also return null]

We're using version 4.1.3 of JDiagram with Java 7.

Initially I was always getting null, even when I 'dropped' on a CompositeNode but now I do get a Point value - unfortunately it doesn't seem to match the CompositeNode I am dropping over.

For example, on a very simple diagram with a single CompositeNode the drop values I get are:

Point x = 19, y = 118

which converts to

Point2D x = 9.75, y = 84.0

(after this I get a number of 'null' drop points as part of the same 'drag and drop' motion)

but the bounds of the single CompositeNode are:

x = 464.25
y = 168.0
width = 100.0
height = 100.0

From running in debug mode, and observing when I get the 'drop' value, this seems to come as the mouse moves from the JTree onto the Diagram, and when I actually 'drop' the item I get a 'null' position. Is there anything I can do about this?

I ran your example code and it worked fine - thanks for supplying that it was very helpful.

I noticed you were using :

importData( JComponent comp, Transferable transferable )
canImport( JComponent comp, DataFlavor[] transferFlavors ) 

whereas I was using the versions which take a single TransferSupport parameter.

I have now changed to using the same methods as your example and it is working fine

Do you have any idea why one method would work and the other not?

All I need to do now is 'refresh' the view/diagram so I can see the new item on my CompositeNode.

Quote:


A similar single-parameter version works for me, I'm guessing that's related to your old code not checking if target is a DiagramView before converting mouse position -

@Override
public boolean importData(TransferSupport support)
{
	if (canImport(support))
	{
		java.awt.Component c = support.getComponent();
		Transferable t = support.getTransferable();

		// Can only drop on the flow chart control
		if (!(c instanceof DiagramView))
			return false;

		if (t.isDataFlavorSupported(DataFlavor.stringFlavor))
		{
			try
			{
				String text = (String)t.getTransferData(DataFlavor.stringFlavor);

				DiagramView view = (DiagramView)c;
				Diagram diagram = view.getDiagram();

				Point mousePosition = view.getMousePosition(true);
				Point2D diagPoint = view.deviceToDoc(mousePosition);
				DiagramNode node = diagram.getNodeAt(diagPoint);
				if (node instanceof TableNode)
				{
					TableNode table = (TableNode)node;
					int lastRow = table.addRow();
					table.getCell(0,  lastRow).setText(text);
				}
				else
				{
					diagram.getFactory().createTableNode(
						diagPoint.getX(), diagPoint.getY(), 50, 80, 1, 0);
				}
			}
			catch (Exception e)
			{
				e.printStackTrace();
			}
		}
	}

	return false;
}

@Override
public boolean canImport(TransferSupport support)
{
	DataFlavor[] flavors = support.getDataFlavors();

	for (int i = 0; i < flavors.length; i++)
	{
		if (DataFlavor.stringFlavor.equals(flavors[i]))
			return true;
	}

	return false;
} 

Regards,
Slavcho
Mindfusion