Android add progress in action bar tutorial

This tutorial is form This blog, thanks.

private Menu optionsMenu;

// create options menu
@Override
public boolean onCreateOptionsMenu(Menu menu) {
 this.mOptionsMenu = menu;
 MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.activity_action_bar_main, menu);
    return super.onCreateOptionsMenu(menu);
}

// change action button state (progress or refresh image)
public void setRefreshActionButtonState(final boolean refreshing)
{
    if (mOptionsMenu != null)
    {
        final MenuItem refreshItem = mOptionsMenu.findItem(R.id.airport_menuRefresh);
        if (refreshItem != null)
        {
            if (refreshing) {
                refreshItem.setActionView(R.layout.actionbar_indeterminate_progress);
            } else {
                refreshItem.setActionView(null);
            }
        }
    }
}

//activity_action_bar_main.xml
<menu xmlns:android="http://schemas.android.com/apk/res/android" >
    <item android:id="@+id/airport_menuRefresh"
         android:title=""
         android:alphabeticShortcut="r"
         android:orderInCategory="1"
         android:showAsAction="always" />
</menu>

// actionbar_indeterminate_progress.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:layout_height="wrap_content"
   android:layout_width="56dp"
   android:minWidth="56dp">
    <ProgressBar android:layout_width="32dp"
       android:layout_height="32dp"
       android:layout_gravity="center"/>
</FrameLayout>