How to use Android Material theme with no action bar

I am trying to use the Android Material theme without an title/action bar using the values-v21 folder. I can't seem to get the title/action bar to be hidden via the theme though. Anyone get this to work?

Here is my theme code:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <style name="CustomTheme" parent="@android:style/Theme.Material">
        <!-- Customize your theme using Material Design here. -->
        <item name="android:actionBarSize">0dp</item>
        <item name="android:windowTitleSize">0dp</item>
    </style>
</resources>