Magento required module not found

Question

I've recently started doing Magento tutorials, since I'm starting a Magento job soon and they've asked me to study up on it so that I don't end up completely out of my depth when I start there.

I'm currently going through this and have hit a snag on page 11. At least, I think I have. I'm not sure, which is why I'm posting this question.

At this point, I have the following:

app/etc/modules/Magentostudy_News.xml

<?xml version="1.0"?>
<config>
    <modules>
        <Magentostudy_News>
            <active>true</active>
            <codePool>community</codePool>
            <depends>
                <Mage_adminhtml/>
            </depends>
        </Magentostudy_News>
    </modules>
</config>

app/code/community folder structure

Magentostudy
  News
    Block
    controller
    data
      magentostudy_news_setup
    etc
      config.xml
    Helper
    Model
    sql
      magentostudy_news_setup

app/code/community/Magentostudy/News/etc/config.xml

<?xml version="1.0"?>
<config>
    <modules>
        <Magentostudy_News>
            <version>1.0.0.0.1</version>
        </Magentostudy_News>
    </modules>

    <global>
        <models>
            <magentostudy_news>
                <class>Magentostudy_News_Model</class>
                <resourceModel>news_resource</resourceModel>
            </magentostudy_news>

            <news_resource>
                <class>Magentostudy_New_Model_Resource</class>
                <entities>
                    <news>
                        <table>magentostudy_news</table>
                    </news>
                </entities>
            </news_resource>
        </models>

        <helpers>
            <magentostudy_news>
                <class>Magentostudy_News_Helper</class>
            </magentostudy_news>
        </helpers>

        <blocks>
            <magentostudy_news>
                <class>Magentostudy_News_Block</class>
            </magentostudy_news>
        </blocks>

        <resources>
            <magentostudy_news_setup>
                <setup>
                    <module>Magentostudy_News</module>
                    <class>Mage_Core_Model_Resource_Setup</class>
                </setup>
            </magentostudy_news_setup>
        </resources>

        <events>
            <before_news_item_display>
                <observers>
                    <magentostudy_news>
                        <class>magentostudy_news/observer</class>
                        <method>beforeNewsDisplayed</method>
                    </magentostudy_news>
                </observers>
            </before_news_item_display>
        </events>
    </global>

    <frontend>
        <routers>
            <magentostudy_news>
                <use>standard</use>
                <args>
                    <module>Magentostudy_News</module>
                    <frontName>news</frontName>
                </args>
            </magentostudy_news>
        </routers>
        <layout>
            <updates>
                <magentostudy_news>
                    <file>magentostudy_news.xml</file>
                </magentostudy_news>
            </updates>
        </layout>
    </frontend>
    <Admin>
        <routers>
            <adminhtml>
                <args>
                    <modules>
                        <Magentostudy_News before="Mage_adminhtml">Magentostudy_News_adminhtml</Magentostudy_News>
                    </modules>
                </args>
            </adminhtml>
        </routers>
    </Admin>
    <adminhtml>
        <layout>
            <updates>
                <magentostudy_news>
                    <file>magentostudy_news.xml</file>
                </magentostudy_news>
            </updates>
        </layout>
    </adminhtml>
    <default>
        <news>
            <view>
                <enabled>1</enabled>
                <items_per_page>20</items_per_page>
                <days_difference>3</days_difference>
            </view>
        </news>
    </default>
</config>

In other words, I have the bare basic start of a new Module.

I tried checking the admin configuration panel to ensure that my module was being picked up. I have disabled my cache, and double checked to make sure that nothing was actually cached.

When I try to access any page, I get the following error:

Module "Magentostudy_News" requires module "Mage_adminhtml".

#0 D:\Work\Development\wamp\www\magento1\app\code\core\Mage\Core\Model\Config.php(849): Mage::throwException('Module "Magento...')
#1 D:\Work\Development\wamp\www\magento1\app\code\core\Mage\Core\Model\Config.php(812): Mage_Core_Model_Config->_sortModuleDepends(Array)
#2 D:\Work\Development\wamp\www\magento1\app\code\core\Mage\Core\Model\Config.php(315): Mage_Core_Model_Config->_loadDeclaredModules()
#3 D:\Work\Development\wamp\www\magento1\app\code\core\Mage\Core\Model\App.php(425): Mage_Core_Model_Config->loadModules()
#4 D:\Work\Development\wamp\www\magento1\app\code\core\Mage\Core\Model\App.php(354): Mage_Core_Model_App->_initModules()
#5 D:\Work\Development\wamp\www\magento1\app\Mage.php(684): Mage_Core_Model_App->run(Array)
#6 D:\Work\Development\wamp\www\magento1\index.php(83): Mage::run('', 'store')
#7 {main}

I think I might have made a mistake somewhere in the config.xml, but I have compared my code with the tutorial and I can't find anything wrong.

Is there anything else that I missed? The tutorial treats Mage_adminhtml as though it's part of the core Magento package, but I am not sure.

Any help at this point would be greatly appreciated.

Answer 1

In your module file app/etc/modules/Magentostudy_News.xml the line <Mage_adminhtml/> should be <Mage_Adminhtml/>

Notice the captial letter for Adminhtml.

You're telling Magento that your module depends on a module named Mage_adminhtml, Magento then tries to locate this but as it cant find it, it throws an Exception.

Welcome to Magento!