Android : How to add spinner in action bar menu items

I have searched a-lot about this but every one just changing the title into spinner. I want some thing like if I add menu item and add this in its code.

    <item 
    android:id="@+id/spListOpt"
    android:showAsAction="always"
    android:actionViewClass="android.widget.Spinner"
    android:title="@string/logout"
          />

Saw this on stack over flow but it doesn't show anything on action bar. Attaching picture for better understanding.