title: gravity="fill_vertical" vs. layout_height="fill_parent" in Android
body: <p>Why does <code>gravity</code> offer a "fill_vertical" option? How is this any different from setting <code>layout_height</code> "fill_parent"? What if I choose a fixed <code>layout_height</code> and "fill_vertical" for gravity? Won't this contradict?</p>