I had a rather basic navigation drawer working pretty well -- a simple ListView. But I need a title above the selectable items, so (see below) modified the XML for the draw
The layout_gravity attribute determines which child View acts as the drawer in a DrawerLayout. Currently, neither of the direct children of your DrawerLayout has that attribute set, so both are just filling it, with the LinearLayout on top, covering the content RelativeLayout.
Move android:layout_gravity="left" from the ListView to the LinearLayout.