Magento - How override admin Sales Totals block (Mage_Adminhtml_Block_Sales_Totals) - magento

Question

I am trying to override the admin Sales Totals block (Mage_Adminhtml_Block_Sales_Totals) situated under "/app/code/core/Mage/Adminhtml/Block/Sales/Totals.php"
I declare my module like this:
<?xml version="1.0" encoding="UTF-8"?>
<config>
<modules>
<CompanyName_Adminhtml>
<version>0.1.0</version>
</CompanyName_Adminhtml>
</modules>
<global>
<blocks>
<companyname_adminhtml>
<class>CompanyName_Adminhtml_Block_Adminhtml_Sales_Totals</class>
</companyname_adminhtml>
<adminhtml>
<rewrite>
<sales_totals>CompanyName_Adminhtml_Block_Adminhtml_Sales_Totals</sales_totals>
</rewrite>
</adminhtml>
</blocks>
</global>
</config>
My module class path is like this:
local/CompanyName_Adminhtml/Block/Adminhtml/Sales/Totals.php
and My class code start like this:
class CompanyName_Adminhtml_Block_Adminhtml_Sales_Totals extends Mage_Adminhtml_Block_Sales_Totals {
// block methods goes here..
}
Unfortunately the class override don't works and I don't get any errors in the log files.
I am using Magento Version 1.7.0.2
In the magento backoffice I can see my module as enabled.
Any help?

Answer 1

Try Overriding the individual Totals.php block which is at the location Mage/AdminHtml/Block/Sales/Order/ file rather than the main Totals.php under the Mage/AdminHtml/Block/Sales/ folder.
It worked for me. As i wanted to show one more row in the order-totals block.

Answer 2

<?xml version="1.0" encoding="UTF-8"?>
<config>
<modules>
<CompanyName_Adminhtml>
<version>0.1.0</version>
</CompanyName_Adminhtml>
</modules>
<global>
<blocks>
<companyName_adminhtml>
<class>CompanyName_Adminhtml_Block</class>
</companyName_adminhtml>
<companyname_adminhtml>
<class>CompanyName_Adminhtml_Block_Adminhtml_Sales_Totals</class>
</companyname_adminhtml>
<adminhtml>
<rewrite>
<sales_order_totals>CompanyName_Adminhtml_Block_Adminhtml_Sales_Totals</sales_totals>
</rewrite>
</adminhtml>
</blocks>
</global>
</config>
then class
class CompanyName_Adminhtml_Block_Adminhtml_Sales_Order_Totalsextends Mage_Adminhtml_Block_Sales_Order_Totals {
protected function _initTotals() {
parent::_initTotals();
$this->_totals['foo_total'] = new Varien_Object(array(
'code' => 'purchasewrapping_total',
'value' => $this->getSource()->getFooTotal(),
'base_value'=> $this->getSource()->getBaseFooTotal(),
'label' => $this->helper('sales')->__('Foo'),
));
return $this;
}
}`enter code here`
Mage_Adminhtml_Block_Sales_Order_Totals is extends at Mage_Adminhtml_Block_Sales_Totals
and here you can extend and write your changes