CODEWITHSUNDEEP
eclipse-plugineclipse-rcp
Michael K.
Michael K.

Reputation: 1788

Enable / Disable Menuitem

I'm writing a RCP App with target-platform 3.7. I like to enable a menuItem only if a specific view is active otherwise it should be disabled. I try it via expression like shown in the plugin.xml below, but the menuItem is always active.

 <extension
         point="org.eclipse.ui.commands">
      <command
            defaultHandler="pgui.handler.SaveHandler"
            id="pgui.rcp.command.save"
            name="Save">
      </command>
   </extension>
   <extension
     point="org.eclipse.ui.views">
     <view
          allowMultiple="true"
          class="pgui.view.LogView"
          id="pgui.view.LogView"
          name="logview"
          restorable="true">
     </view>
   </extension>
   <extension
         point="org.eclipse.ui.menus">
      <menuContribution
            allPopups="false"
            locationURI="menu:org.eclipse.ui.main.menu">
         <menu
               id="fileMenu"
               label="File">
            <command
                  commandId="pgui.rcp.command.save"
                  label="Save"
                  style="push"
                  tooltip="Save the active log file.">
            </command>
         </menu>
      </menuContribution>
    </extension>
    <extension
         point="org.eclipse.ui.handlers">
      <handler
            commandId="pgui.rcp.command.save">
         <activeWhen>
            <with
                  variable="activePart">
               <instanceof
                     value="pgui.view.LogView">
               </instanceof>
            </with>
         </activeWhen>
      </handler>
   </extension>

Upvotes: 1

Views: 2840

Answers (1)

stracka
stracka

Reputation: 1023

First, remove the defaultHandler from your command.

Next, add your handler class to your handler extension point instead.

Basically, the mechanism allows you to define multiple handlers for the same command, using different activeWhen expressions to have the command handled by different handler classes in different circumstances.

If all of the activeWhen expressions on all of the defined handlers for a command evaluate to false, and there is a defaultHandler defined for the command itself, then that default handler will be used for the command. The command will, essentially, always be active, since there's always a default handler around to handle it.

For example, if you had both your existing LogView, and another view full of unicorns, and you wanted to use the same pgui.rcp.command.save command to handle the saving of items from either view:

<extension point="org.eclipse.ui.commands">
    <command
        id="pgui.rcp.command.save"
        name="Save">
    </command>
</extension>
:
<extension point="org.eclipse.ui.handlers">
    <handler
        class="pgui.handler.SaveLogHandler"
        commandId="pgui.rcp.command.save">

        <activeWhen>
            <with variable="activePart">
                <instanceof value="pgui.view.LogView">
                </instanceof>
            </with>
        </activeWhen>
    </handler>
</extension>
:
<extension point="org.eclipse.ui.handlers">
    <handler
        class="pgui.handler.SaveUnicornHandler"
        commandId="pgui.rcp.command.save">

        <activeWhen>
            <with variable="activePart">
                <instanceof value="pgui.view.UnicornView">
                </instanceof>
            </with>
        </activeWhen>
    </handler>
</extension>

Upvotes: 3

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