Could you post your manifest? It might help get to the bottom of the issue.
Also, take a look at this thread, as it seems to be what you want.
Basically, create subpackages for each aspect. So they would be
com.yourapp.model
com.yourapp.view
com.yourapp.controller
and your manifest would look like
<manifest package="com.yourapp" . . . >
<application . . .>
<activity android:name=".model.Activity1" . . . />
<activity android:name=".view.Activity2" . . . />
<activity android:name=".controller.Activity3" . . . />
</application>
</manifest>
But you might not have activities in each of these packages, that's just to show you how you could access them if you need to.