treeViewer.addDoubleClickListener(new IDoubleClickListener() {		@Override	public void doubleClick(DoubleClickEvent event) {				IStructuredSelection is = (IStructuredSelection)event.getSelection();		Object obj = is.getFirstElement();		//自定义的节点对象		Node node = (Node)obj;		TreeItem[] items = treeViewer.getTree().getSelection();		 			if(null == items || items.length == 0){				return;			}			if(items[0].getExpanded()){				items[0].setExpanded(false);			}else{			 				//从选中的节点处展开				treeViewer.expandToLevel(node, 1);			}		 			}});