in the controller

gistfile1.php

<?php
  function add()
  {
    $this->setupLayout('Add page',array(),true); // this set's the title, navigation bar, and whether this is an admin view of frontend view
    $this->save();
  }

  function edit($id=null)
  {
    $this->setupLayout('Edit page',array(),true);
    $this->save($id);
  }

  function save($id=null)
  {
    // is it a new form..
    if (!$this->input->post('posted')){ // have a form_hidden('posted','true') in the view
      $this->layout->view('admin/pages/save',array('id'=>$id));
    } else {
      // validate
      $this->form_validation->set_rules('title','Title','required');
      if ($this->form_validation->run() == FALSE){
        $this->layout->view('admin/pages/save',array('id'=>$id)); // repopulate the form on validation fail
      } else {
        // save the form through the model
        $this->page->save($id);
        // go to a thank you page or back to an index
        redirect('/admin/pages/manage'); // the index page for the backend is called manage.php as index is alread taken for the frontend
      }
    }
  }