Save color values in theme variables and reference them in activty xml?

I want to provide different app themes for my users to chose from. What I want to do is to define a Color1 and Color2 in my theme and reference these colors in the activies my xml.

Something like:

<style name="Theme.LightTheme" parent="Theme.General">
    <item name="android:color1">#000000</item>
    <item name="android:color2">#ffffff</item>
</style>

And then on an activity xml:

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textColor="?android:color1"
        android:background="?android:color2" />

How can this be done?