Help understanding layout files and where action links to

Question

I'm working on creating a custom report and rather than just cut and paste code I'm trying to understand how magento layout files work better.

Magento 1.9 I'm looking at a report Products -> Most Viewed.

I've found the menu item added in

app/code/core/Mage/Reports/etc/adminhtml.xml

Obviously I removed a lot to just show what I'm asking questions about.

<config>
    <menu>
        <report translate="title" module="reports">
            <children>
                <products translate="title" module="reports">
                    <children>      <!-- Menu Item -->
                        <viewed translate="title" module="reports">
                            <title>Most Viewed</title>
                            <action>adminhtml/report_product/viewed</action>
                        </viewed>
                    </children>
                </products>
            </children>
        </report>
    </menu>
</config>

Where it says:

<action>adminhtml/report_product/viewed</action>

I know that accesses

app/code/core/Mage/Adminhtml/Block/Report/Product

My question is, does the /viewed mean it opens Viewed.php, or subfolder /Viewed?

If the answer is it opens Viewed.php, what then opens the file /Viewed/Grid.php?

Answer 1

It calls the Viewed.php file.

That file extends the app/code/core/Mage/Adminhtml/Block/Widget/Grid/Container.php file's class.

In that file, you will find the protected function _prepareLayout() which uses the setChild method to assign the appropriate file as Mage/Adminhtml/Block/***/Grid.php

Answer 2

Found this tutorial that helped me understand the magento file structure.

http://devdocs.magento.com/guides/m1x/magefordev/mage-for-dev-3.html