1.9 new Category admin grid can't get values

Question

I want to link cms/blocks to categories. Then I created a Grid inspirited by the Product grid, this show blocks and this grid allow 2 things (select blocks with a checkbox and modify it's position with a textfield).

But when the user click on save I don't know how to get this grid values. Can you help me please ?

Here is the content of my grid class :

class Namespace_Catalog_Block_Adminhtml_Catalog_Category_Tab_About extends Mage_Adminhtml_Block_Widget_Grid
{
    protected $_aboutCollection = null;

    /** Mage_Cms_Model_Resource_Block_Collection $_aboutCollection */

    public function __construct()
    {
        parent::__construct();
        $this->setId('catalog_category_about');
        $this->setDefaultSort('order');
        $this->setUseAjax(true);
    }

    protected function _addColumnFilterToCollection($column)
    {
        // Set custom filter for in category flag
        if ($column->getId() == 'block_used_in_category') {
            $blockIds = $this->_getUsedBlocks();
            if (empty($blockIds)) {
                $blockIds = 0;
            }
            if ($column->getFilter()->getValue()) {
                $this->getCollection()->addFieldToFilter('block_id', array('in'=>$blockIds));
            }
            elseif(!empty($blockIds)) {
                $this->getCollection()->addFieldToFilter('block_id', array('nin'=>$blockIds));
            }
        }
        else {
            parent::_addColumnFilterToCollection($column);
        }
        return $this;
    }

    protected function _prepareCollection()
    {
        if (!$this->_aboutCollection) {
            $categoryId = (int)$this->getRequest()->getParam('id', 4);
            $aboutTableName = Mage::getSingleton('core/resource')->getTableName('namespace_catalog/about');

            /** @var Mage_Cms_Model_Resource_Block_Collection $collection */
            $collection = Mage::getModel('cms/block')->getCollection();
            $collection->getSelect()
                ->joinLeft(
                    array('catalog_block_about' => $aboutTableName),
                    'main_table.block_id = catalog_block_about.block_id AND catalog_block_about.category_id = ' . $categoryId,
                    array('order')
                );
            $collection->addFieldToFilter('identifier', array('like' => 'apropos_%'));
            $this->_aboutCollection = $collection;
        }

        $this->setCollection($this->_aboutCollection);

        return parent::_prepareCollection();
    }

    protected function _prepareColumns()
    {
        $this->addColumn('block_used_in_category', array(
            'header_css_class' => 'a-center',
            'type' => 'checkbox',
            'name' => 'block_used_in_category',
            'values' => $this->_getUsedBlocks(),
            'align' => 'center',
            'index' => 'block_id'
        ));
        $this->addColumn('block_identifier', array(
            'header' => Mage::helper('catalog')->__('Block id'),
            'sortable' => true,
            'width' => '60',
            'index' => 'identifier'
        ));
        $this->addColumn('block_title', array(
            'header' => Mage::helper('catalog')->__('Block title'),
            'sortable' => true,
            'width' => '60',
            'index' => 'title'
        ));
        $this->addColumn('block_order', array(
            'header' => Mage::helper('catalog')->__('Block position'),
            'sortable' => true,
            'width' => '1',
            'index' => 'order',
            'editable' => true,
            'renderer'  => 'adminhtml/widget_grid_column_renderer_input'
        ));
        return parent::_prepareColumns();
    }

    protected function _getUsedBlocks()
    {
        $array = [];
        if (!$this->getCollection()) {
            $this->_prepareCollection();
        }

        foreach ($this->getCollection() as $item) {
            if ($item->getOrder() !== null) {
                $array[] = $item->getId();
            }
        }

        return $array;
    }
}

This will pick all CMS block with an identifier starting by "apropos_" and join the results with a new table I created which contain (block_id,category_id,order).

Now I want, when the user click on save, saving the grid informations (the order, and if the checkbox is checked). So to save this I create a new observer about the event "catalog_category_save_after" but in my function when I write a Mage::app()->getRequest()->getPost() I don't get the informations.

I tried to follow this post but I don't understand how it results to get it's data by using the same method as mine.

Answer 1

I found out that the only clean way to do this is by passing by the template app/design/adminhtml/default/default/template/catalog/catego‌​ry/edit/form.phtml and modify the JS to create a front input like the category product tab does.

I create generic functions to did this instead of copy/past default functions. This may allow me to add multiple new tabs easier.