Java/GWT/ScrollListener

Use ScrollListener

   <source lang="java">

package com.jexp.gwt.client; import com.google.gwt.core.client.EntryPoint; import com.google.gwt.user.client.ui.CheckBox; import com.google.gwt.user.client.ui.ruposite; import com.google.gwt.user.client.ui.Label; import com.google.gwt.user.client.ui.ScrollListener; import com.google.gwt.user.client.ui.ScrollPanel; import com.google.gwt.user.client.ui.VerticalPanel; import com.google.gwt.user.client.ui.Widget; import com.google.gwt.user.client.ui.RootPanel; public class GWTClient implements EntryPoint{

 public void onModuleLoad() {
   LicensePanel e = new LicensePanel("License: scroll to enable the check box");
   
   RootPanel.get().add(e);
 }

} class LicensePanel extends Composite {

   private VerticalPanel vPanel = new VerticalPanel(); 
   final Label text;
   private ScrollPanel sPanel = new ScrollPanel();
   private CheckBox accept = new CheckBox("Accept Terms");
   public LicensePanel(final String licenseText) {
       text = new Label(licenseText); 
       
       sPanel.setAlwaysShowScrollBars(true);
       sPanel.setHeight("100px");
       sPanel.setWidth("200px");        
       sPanel.add(text);   
       
       accept.setChecked(false);
       accept.setEnabled(false); 
       
       vPanel.add(sPanel);
       vPanel.add(accept);
       initWidget(vPanel);
       
       sPanel.addScrollListener(new ScrollListener() {            
               public void onScroll(Widget sender, int x, int y) {
                   Widget textItem = sPanel.getWidget();
                   if (sPanel.getOffsetHeight() + y >= textItem.getOffsetHeight())
                   {
                       accept.setEnabled(true);
                   }                    
               }
           });        
       //setStyleName("licensePanel");
   }     
   
   public boolean isAccepted() {
       return accept.isChecked();
   }

}

      </source>