I used a little time to figure this out... I ran it some CastExceptions, but figured out that you can replace you LinearLayout in the layout.xml with the name of the class.
Like this:
<?xml version="1.0" encoding="UTF-8"?>
<LinearLayout android:layout_width="fill_parent" android:layout_height="fill_parent"
xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/llMaster">
<com.ourshoppingnote.RelativeLayoutThatDetectsSoftKeyboard android:background="@drawable/metal_background"
android:layout_width="fill_parent" android:layout_height="fill_parent"
android:id="@+id/rlMaster" >
<LinearLayout android:layout_width="fill_parent"
android:layout_height="1dip" android:background="@drawable/line"></LinearLayout>
....
</com.ourshoppingnote.RelativeLayoutThatDetectsSoftKeyboard>
</LinearLayout>
That way you do not run into any cast issues.
... and if you don't want to do this on every page, I recommend that you use "MasterPage in Android". See the link here: http://jnastase.alner.net/archive/2011/01/08/ldquomaster-pagesrdquo-in-android.aspx