Nesting layout

将页面布局分割为3个部分：左半边的导航（navigation），右上边的（listing）列表，右下边的Detail内容。

public   class  NestingSample  implements  EntryPoint  {   
  
    public void onModuleLoad() {   
        HLayout mainLayout = new HLayout();   
        mainLayout.setWidth100();   
        mainLayout.setHeight100();   
  
        Label navigationLabel = new Label();   
        navigationLabel.setContents("Navigation");   
        navigationLabel.setAlign(Alignment.CENTER);   
        navigationLabel.setOverflow(Overflow.HIDDEN);   
        navigationLabel.setWidth("30%");   
        navigationLabel.setShowResizeBar(true);   
        navigationLabel.setBorder("1px solid blue");   
  
        mainLayout.addMember(navigationLabel);   
  
        VLayout vLayout = new VLayout();   
        vLayout.setWidth("70%");   
  
        Label listingLabel = new Label();   
        listingLabel.setContents("Listing");   
        listingLabel.setAlign(Alignment.CENTER);   
        listingLabel.setOverflow(Overflow.HIDDEN);   
        listingLabel.setHeight("30%");   
        listingLabel.setShowResizeBar(true);   
        listingLabel.setBorder("1px solid blue");   
  
        Label detailsLabel = new Label();   
        detailsLabel.setContents("Details");   
        detailsLabel.setAlign(Alignment.CENTER);   
        detailsLabel.setOverflow(Overflow.HIDDEN);   
        detailsLabel.setHeight("70%");   
        detailsLabel.setBorder("1px solid blue");   
  
        vLayout.addMember(listingLabel);   
        vLayout.addMember(detailsLabel);   
  
        mainLayout.addMember(vLayout);   
        mainLayout.draw();   
    }   
  
}