WordPress: Add filter to control which users see the admin bar.

WordPress Show Admin Bar

/**
 * mm_show_admin_bar function.
 * Filter to control which users see the admin bar.
 * @access public
 * @return false or true if user is admin.
 */
function mm_show_admin_bar() {
	if (current_user_can('administrator')) {
		return true;
	} else {
		return false;
	}
}

// Hide admin bar
add_filter( 'show_admin_bar', 'mm_show_admin_bar' );

WordPress: Show Admin Bar

/**
 * mm_show_admin_bar function.
 * Filter to control which users see the admin bar.
 * @access public
 * @return false or true if user is admin.
 */
function mm_show_admin_bar() {
	if(is_admin())
	{
		return true;
	}
	return false;
}

// Hide admin bar
add_filter( 'show_admin_bar', 'mm_show_admin_bar' );