public void setupUpIndicator(Activity activity) {
        if (mActionBarHelper == null) {
            mActionBarHelper = new ActionBarHelper(activity);
            mThemeUpIndicator = mActionBarHelper.getThemeUpIndicator();

            if (mDrawerIndicatorEnabled) {
                mActionBarHelper.setActionBarUpIndicator(mSlideDrawable,
                        isMenuVisible() ? mDrawerOpenContentDesc : mDrawerClosedContentDesc);
            }
        }
    }
Sets up the drawer indicator. It cna then be shown with {@link #setDrawerIndicatorEnabled(boolean)}.

@param activity The activity the drawer is attached to.
menudrawer/src/net/simonvt/menudrawer/MenuDrawer.java