Can't display GWT DataGrid

Question

So I'm having a heck of a time creating a Datagrid with GWT. I've created my table according the the docs for GWT, and I've added my data, but I can't get it or the datagrid itself to show up at all. What am I missing? I feel I've been tearing my hair out over this. I feel like making an aysnc call might be an issue, but I get no errors. When i compile and execute this portion of my code nothing shows up on the screen and the area where the datagrid is supposed to be on the dock is empty. Am I forgetting something trivial?

        static int orderID = 1001;
        private static List<OrderLine> orderLineList = new ArrayList<OrderLine>();

        final DataGrid<OrderLine> dgOrder = new DataGrid<OrderLine>();
        dgOrder.setWidth("100%");                   

        //set columns
        TextColumn<OrderLine> orderLineIdColumn = new TextColumn<OrderLine>(){
            @Override
            public String getValue(OrderLine object) {
              return Integer.toString(object.getOrderLineID());
            }
        };
        dgOrder.addColumn(orderLineIdColumn, "OrderLine ID");

        TextColumn<OrderLine> productColumn = new TextColumn<OrderLine>(){
            @Override
            public String getValue(OrderLine object) {
              return getProductName(object.getProductNumber());
            }
        };
        dgOrder.addColumn(productColumn, "Product");

        TextColumn<OrderLine> quantityColumn = new TextColumn<OrderLine>(){
            @Override
            public String getValue(OrderLine object) {
              return Integer.toString(object.getQuantity());
            }
        };
        dgOrder.addColumn(quantityColumn, "Quantity");   

        // add data to datagrid
        Ioma.dataservice.getOrderLines(orderID, new AsyncCallback<ArrayList<OrderLine>>(){
            @Override
            public void onFailure(Throwable caught) {// TODO Auto-generated method stub
                System.out.println("error in retrieving GP.getOrderLines" + caught.toString());
            }
            @Override
            public void onSuccess(ArrayList<OrderLine> result) {
                // TODO Auto-generated method stub
               //yes i realize I could also set it to "result" but I use the result in other places as well, I have also tried setting it to result with no success
                orderLineList = result;
                dgOrder.setRowData(0, orderLineList);
            }
        });

        //add datagrid to the dock 
        dock.add(dgOrder, DockPanel.EAST);

        //add dock to mainPanel
        return dock;

Answer 1

When you use the DataGrid you need to give it an explicit size. For CellTable you don't need to so that's why it worked.

When you were using the DataGrid is was there but had both height and width of 0. So you either need to explicitly set the size:

DataGrid<OrderLine> grid = new DataGrid<OrderLine>;
grid.setWidth("500px");
grid.setHeight("600px");
dock.add(dgOrder, DockPanel.EAST);

or you can put the gird in a ProvidesResize widget. So in your case I believe you can make it work with a DockLayoutPanel as opposed to a DockPanel which is what you seem to be using.