Search View in the toolbar gives me null reference

This is the xml code of the menu

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
   <item
       android:id="@+id/search"
       android:title="Busqueda"
       app:showAsAction="always|collapseActionView"
       android:icon="@drawable/ic_search_black_24dp"
       android:actionViewClass="android.support.v7.widget.SearchView"/>
</menu>

This is the code that gives me null reference

@Override
public boolean onCreateOptionsMenu(Menu menu) {

    getMenuInflater().inflate(R.menu.menu_board_activity, menu);

    final MenuItem item = menu.findItem(R.id.search);
    final SearchView searchView = (SearchView) item.getActionView();

    //no instancia el searchView...

    search(searchView);

    return super.onCreateOptionsMenu(menu);
}

This is the error. java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.SearchView.setOnQueryTextListener (android.widget.SearchView $ OnQueryTextListener)' on a null object reference

Any help is appreciated