GWT Drag And Drop Sample with CellTable / DataGrid. The sample is deployed to appengine : http://gwt-dnd-sample.appspot.com/
To make a widget draggable, you have to :
- position the attribute "draggable" to "true" :
widget.getElement().setDraggable(Element.DRAGGABLE_TRUE);
- listen to dragstart event and position the values you want to drag via
event.getDataTransfer().setData("key","value");
To drop in a widget, you have to :
- listen to dragover event. Without it, the drop event is never called!
- listen to drop event and read the dragged values via
event.getDataTransfer().getData("key");