Unidata IDV Workshop for version 6.3 > Java Developer Topics > IDV User Interfaces

We're going to look at how to extend the menu bar.

• In the /home/idv/idv/ucar/unidata/apps/example/resources directory copy the file defaultmenu.xml up a level to the example directory.
• Bring the defaultmenu.xml file into an editor.
• Run the ExampleIdv. Note the new menu entry. For kicks, select Example→Show resources. This shows all of the resources loaded into the ExampleIdv.
• Let's add in a Hello World menu item.
  • Add in the following under the "Example" menu tag.

        <menuitem
           action="jython:idv.helloWorld();"
           label="Hello World"/>
    

  • Run ExampleIdv. Select Example→Hello World
  • We get an error. We need to add the helloWorld method to ExampleIdv:

      public void helloWorld() {
          System.err.println("Hello World");
      }
    

    The method needs to be public.
  • Compile and run again.
• Note that we now have code embedded in our menubar xml file. This might not be good practice. We'll use the "actions"resource to define an action.
  • Copy the file resources/actions.xml to the example directory.
  • This defines an action called "example.helloworld":

      <action
         id="example.helloworld"
         image="/ucar/unidata/apps/example/resources/HelloWorld.gif"
         description="Call hello world"
         action="jython:idv.helloWorld();"/>
    

  • Add the following into the defaultmenu.xml. Note the "action:" prefix.

        <menuitem
           action="action:example.helloworld"
           label="Hello World from action"/>
        <separator/>
    

  • Run ExampleIdv.
  • The example.helloworld action is now also available in the toolbar. Bring up the User Preferences
• So, this added our own menu into the menu bar. How do we not use any of the system menus?
  • Bring up the idv.rbi and change

      <resources name="idv.resource.menubar">
      </resources>
    

    To:

      <resources name="idv.resource.menubar" loadmore="false">
        <resource
           location="/ucar/unidata/apps/example/defaultmenu.xml"/>
      </resources>
    

    The loadmore tells the IDV not to use the system resources.
  • Run the ExampleIdv.
  • Remove the above entries from the example idv.rbi file.
• Now, let's look at the default system menubar in /home/idv/idv/ucar/unidata/idv/resources/defaultmenu.xml
  • Note the "id=" attributes. The IDV uses these ids to know where to dynamically add in different menus, e.g., available windows, display lists, data, etc.

 

Unidata IDV Workshop for version 6.3 > Java Developer Topics > IDV User Interfaces