Time for action – creating an extension

The steps for creating an extension to hide a label when the mouse pointer moves over it are as follows:

1. Create a new Vaadin project with the name extension using your IDE.

2. Create a new server-side extension class:

   public class HideOnHover extends AbstractExtension {
   
     public void extend(Label label) {
       super.extend(label);
     }
   
   }

3. Create a new client side connector (remember to put this class inside a .client package):

   @Connect(HideOnHover.class)
   public class HideOnHoverConnector extends AbstractExtensionConnector {
   
     @Override
     protected void extend(ServerConnector target) {
       final Widget widget = ((ComponentConnector) target).getWidget();
   
       widget.addHandler(new MouseOverHandler() {
         @Override
         public void onMouseOver(MouseOverEvent event) {
           widget.setVisible(false);
         }
       }, MouseOverEvent.getType());
     }
   
   }

4. Use the extension in your UI class:

       Label textField = new Label(
           "Do you dare to put the cursor over...