Creating a fluid panel in GWT to fill the page?

Question

I would like a panel in GWT to fill the page without actually having to set the size. Is there a way to do this? Currently I have the following:

public class Main  implements EntryPoint
{
    public void onModuleLoad()
    {
        HorizontalSplitPanel split = new HorizontalSplitPanel();
        //split.setSize("250px", "500px");
        split.setSplitPosition("30%");

        DecoratorPanel dp = new DecoratorPanel();
        dp.setWidget(split);

        RootPanel.get().add(dp);
    }

}

With the previous code snippet, nothing shows up. Is there a method call I am missing?

Thanks.

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UPDATE Sep 17 '08 at 20:15

I put some buttons (explicitly set their size) on each side and that still doesn't work. I'm really surprised there isn't like a FillLayout class or a setFillLayout method or setDockStyle(DockStyle.Fill) or something like that. Maybe it's not possible? But for as popular as GWT is, I would think it would be possible.

UPDATE Sep 18 '08 at 14:38

I have tried setting the RootPanel width and height to 100% and that still didn't work. Thanks for the suggestion though, that seemed like it maybe was going to work. Any other suggestions??

Answer 1

Google has answered the main part of your question in one of their FAQs: http://code.google.com/webtoolkit/doc/1.6/FAQ_UI.html#How_do_I_create_an_app_that_fills_the_page_vertically_when_the_b

The primary point is that you can't set height to 100%, you must do something like this:

final VerticalPanel vp = new VerticalPanel();
vp.add(mainPanel);
vp.setWidth("100%");
vp.setHeight(Window.getClientHeight() + "px");
Window.addResizeHandler(new ResizeHandler() {

  public void onResize(ResizeEvent event) {
    int height = event.getHeight();
    vp.setHeight(height + "px");
  }
});
RootPanel.get().add(vp);

Answer 2

Ben's answer is very good, but is also out of date. A resize handler was necessary in GWT 1.6, but we are at 2.4 now. You can use a DockLayoutPanel to have your content fill the page vertically. See the sample mail app, which uses this panel.