TransferHandler exportAsDone called before exportAsDrag returns

[FredK]

I have a subclass of JPanel for which I am trying to implement
drag-and-drop. I add a mouse listener to the component, and in
its mousePressed() method I call
JComponent c = (JComponent)event.getSource();
TransferHandler th = c.getTransferHandler();
th.exportAsDrag( comp, event, TransferHandler.COPY );

The problem is that the handler's exportAsDone() method is
called immediately - before exportAsDrag() returns, and
before the mouse is moved or released.

--
Fred K

[Lew]

Can you provide an SSCCE?

http://sscce.org/

The problem appears to be in the part of the code you haven't shown us.

Are you managing events on the EDT properly?

--
Lew

[FredK]

On Monday, June 10, 2013 3:14:11 PM UTC-7, Lew wrote:
> FredK wrote: > I have a subclass of JPanel for which I am trying to implement > drag-and-drop. I add a mouse listener to the component, and in > its mousePressed() method I call > JComponent c = (JComponent)event.getSource(); > TransferHandler th = c.getTransferHandler(); > th.exportAsDrag( comp, event, TransferHandler.COPY ); > > The problem is that the handler's exportAsDone() method is > called immediately - before exportAsDrag() returns, and > before the mouse is moved or released. Can you provide an SSCCE? http://sscce.org/ The problem appears to be in the part of the code you haven't shown us. Are you managing events on the EDT properly? -- Lew

I hadn't realized that JPanel (or I guess JComponent) had built-in DnD for bean properties - didn't see any mention of it in the Javadoc tutorials.
I now have it working - I had been using "text" as the argument for TransferHandler, but my component did not have a "text" property.

For example, this does work (and works for "text" when I add a "text" property to my panel):

package boeing.geoduck.viewer.swingitems;

import java.awt.BorderLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.TransferHandler;

public class DragTest {

public static void main( String args[] ) {
SwingUtilities.invokeLater( new Runnable() {
public void run() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
frame.setSize( 300, 150 );

JPanel w = new JPanel();
frame.add( w, BorderLayout.CENTER );

w.setTransferHandler( new TransferHandler( "background" ) );

w.addMouseListener( new MouseAdapter() {
@Override
public void mousePressed( MouseEvent me ) {
JComponent comp = (JComponent) me.getSource();
TransferHandler handler = comp.getTransferHandler();
int actions = handler.getSourceActions( comp );
System.out.println( actions );
handler.exportAsDrag( comp, me, TransferHandler.COPY );
}
} );

frame.setVisible( true );
}
} );
}
}

--
Fred K