Android : How to add an action only to Strings.xml files in Android in IntelliJIdea Plugin development

I created a IntelliJIdea Plugin, using the actions entry in plugin.xml like

  <actions>
    <!-- Add your actions here -->
    <group id="AL.Localize" text="_Localize" description="Localize strings" >
      <add-to-group group-id="ProjectViewPopupMenu"/>

      <action id="AL.Convert" class="action.ConvertToOtherLanguages" text="Convert to other languages"
              description="Convert this strings.xml to other languages that can be used to localize your Android app.">

      </action>
    </group>
  </actions>

Using this setting, my action will appear after user right-click a file. Like this:

The problem is that the Convert to other languages menu shows all the time, I only want this menu show when user right-click on the string.xml file, like the Open Translation Editor(Preview) menu does. (Open Translation Editor(Preview) is a feature Android Studio introduced in version 0.8.7)

What should I do?