code: private void initializeDrawer() {
      mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
      mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout, R.drawable.ic_drawer,
          R.string.show, R.string.hide);
      mDrawerLayout.setDrawerListener(mDrawerToggle);
      getActionBar().setDisplayHomeAsUpEnabled(true);
      mDrawerToggle.syncState();
    }
docs: Sets up the UI for the navigation drawer.