Scout/HowTo/5.0/Hide or disable menu items dynamically

The Scout documentation has been moved to https://eclipsescout.github.io/.

This how-to describes how to dynamically hide or disable menu entries.

Hiding and disabling menu items

Context menus added to tables or form fields already support showing and hiding of menu entries depending on the number of selected elements (mostly relevant for tables) using the "Single Selection", "Multi Selection" and "Empty Space" actions:

In addition, it is also possible to use additional criteria to either show/hide or enable/disable (shown but greyed out) a menu item by overwriting its exePrepareAction() method:

In this method, any criteria can be evaluated and depending on the result of the evaluation the user can then decide to hide/show/disable/enable the menu item:

     @Override
     protected void execOwnerValueChanged(Object newValue) throws ProcessingException {
       super.execOwnerValueChanged(newValue);
       boolean visible = complexCalculation();
       boolean enabled = anotherComplexCalculation();
       
       setVisible(visible);
       setEnabled(visible && enabled);
     }

The following screenshot illustrates the effects of the various combinations on AnotherMenuItem:

Adding separators to menus

In order to add a separator to a menu, a new menu item with its Separator property set to true must be added to a menu:

   @Order(30.0)
public class SeparatorMenu extends AbstractMenu {
  
  @Override
  protected boolean getConfiguredSeparator() {
    return true;
  }
}