Android : Injecting attributes into drawable resources files on Android

I'm trying to find the best way to reuse resource files. In this example, I'm trying to create a ghost button for Android. I have a ghost button drawable xml file that defines the background, but I would like to be able to specify the color (specifically without using theme based defined colors).

ghost.xml:

  <shape
  android:shape="rectangle">
  <corners android:radius="@dimen/ghost_button_corner" />
  <solid android:color="@android:color/transparent" />
  <stroke android:width="@dimen/ghost_button_stroke_size" android:color="?attr/ghost_color" /></shape>

ghost_style.xml:

<!-- STYLABLE -->
<attr name="ghost_color" format="reference" />

<!-- STYLES -->
<style name="GhostButtonBlack" parent="@style/GhostButton">
    <item name="ghost_color">@android:color/black</item>
</style>

<style name="GhostButtonWhite" parent="@style/GhostButton">
    <item name="ghost_color">@android:color/white</item>
</style>

<!-- BASE -->
<style name="GhostButton" parent="android:style/Widget.Button">
    <item name="android:textSize">@dimen/ghost_button_text_size</item>
    <item name="android:textColor">?attr/ghost_color</item>
    <item name="android:background">@drawable/ghost</item>
</style>

within layout.xml:

    <Button
    style="@style/GhostButtonWhite"
    android:layout_width="match_parent"
    android:layout_height="50dp"
    android:layout_margin="5dp"
    android:text="White Ghost Button" />

But I'm currently getting the following exception:

Caused by: java.lang.RuntimeException: Failed to resolve attribute at index 5 
at android.content.res.TypedArray.getColorStateList(TypedArray.java:425)
at android.widget.TextView.<init>(TextView.java:987)