Clear Magento cache is essential after layout xml update

说来懊恼，为了让Magento product list能够显示自定义属性的值，我查看了magento wiki 和 forum 上几十个帖子，众说纷纭，我也不知道哪个是对的，或者哪个针对当前1.1.8可用。一个个实验下来，排列组合了不下100种可能，比如：

• 有人说layout add this line: my_attribute，另有人说是my_attribute
• 有人说要用$_product->getMyAttribute()，也有人说用$_product->getAttribute(‘my_attribute’)，也有人说用$_product->getData(‘my_attribute’)，也有人说用$_product->getAdditionalData(‘my_attribute’)，还有人说用$_product->getResource()->getAttribute(‘my_attribute’)->getFrontend()->getValue($_product))
• 还有人说Create separate module for your customization, Name it ‘Mycustomization’
  (can be changed).
  Then do this:
  1. Create file app/etc/modules/Mycustomization.xml

  <?xml version="1.0"?>
  <config>
  <modules>
  <Mycustomization>
  <active>
  true
  </active>
  <codePool>
  local
  </codePool>
  </Mycustomization>
  </modules>
  </config>
  

  2. Create folder app/code/local/Mycustomization and inside it app/code/local/Mycustomization/etc/

  3. Create file
  app/code/local/Mycustomization/etc/config.xml

  <?xml version="1.0"?>
  <config>
  <modules>
  <Mycustomization>
  <version>
  0.0.1
  </version>
  </Mycustomization>
  </modules>
  <frontend>
  <product>
  <collection>
  <attributes>
  <designer/>
  </attributes>
  </collection>
  </product>
  </frontend>
  </config>
  

  Once done on the frontend in all product collections you will have designer attribute loaded automatically.

• 还有Create a file app/etc/modules/category_product_attributes.xml with the following:

  <?xml version="1.0"?>
  <config>
  <frontend>
  <product>
  <collection>
  <attributes>
  <attributeyouwant/>//This is your attribute
  </attributes>
  </collection>
  </product>
  </frontend>
  </config>
  

• 等等

最后发现所有组合都不起作用，除非清除magento cache 让 layout xml 生效。