For Android styles, you reference the preset attributes of R.attr. Here, you want to to reference android:buttonStyle. You can try this :
<style name="ApplicationStyle" parent="android:Theme">
<item name="android:buttonStyle">@style/ButtonAppTheme</item>
</style>
<Button
android:layout_width="match_parent"
android:layout_height="@dimen/button_height"
style="@style/ButtonAppTheme"
android:text="@string/my_groups"
android:id="@+id/myGroups_btn"
android:layout_alignParentBottom="true"
android:onClick="myGroups" />
For Android styles, you reference the preset attributes of R.attr. Here, you want to to reference android:buttonStyle. You can try this :
<style name="ApplicationStyle" parent="android:Theme">
<item name="android:buttonStyle">@style/yourButton</item>
</style>
Also look in this [Themes and Styles][1]
[1]: http://android-pro.blogspot.com/2010/08/using-themes-and-styles-in-android.html
