I have an application with a split action bar loading an action menu.
I changed the actionbar for the new toolbar and replaced the split actionbar by an other toolba
I've also been trying to find an answer to this question the past couple weeks. And the closest thing I have found takes advantage of the fact that the Toolbar is just a ViewGroup. All you need to do is create a menu_items layout that is just a LinearLayout with equally weighted menu items added. I know this isn't an ideal solution but I haven't found anyway to spread out the items while using the default menu.
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar_btm"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:minHeight="?attr/actionBarSize"
android:background="@color/toolbar_bkgnd"
android:layout_alignParentBottom="true"
app:theme="@style/ThemeOverlay.AppCompat.ActionBar" >
<include layout="@layout/menu_items"/>
</android.support.v7.widget.Toolbar>
In this case, Chris Banes recommends to use ActionMenuView instead of Toolbar (see the link below, reply #6). Besides that, in this link you can find a solution where the guy subclassed Toolbar in order to the split works right.
https://code.google.com/p/android/issues/detail?id=77632#c2
Hope it helps you!