Magento 布局 XML 中的“更新”元素有什么作用？

Question

现在我正在探索 Magento 管理部分的内部结构，偶然发现了这段 XML：

文件：app/design/adminhtml/default/default/layout/catalog.xml，第 55 行左右

50            <block type="core/template" template="catalog/wysiwyg/js.phtml"/>
51        </reference>
52    </adminhtml_catalog_product_new>
53    
54    <adminhtml_catalog_product_edit>
55        <update handle="editor"/>
56        <reference name="content">
57            <block type="adminhtml/catalog_product_edit" name="product_edit"></block>
58        </reference>

<update /> 标签有什么作用？

Answer 1

<update> 基本上是在拉另一个句柄。

假设你有这个：

<layout>
   <foo>
      <reference name="header">
          <block type="cms/block" name="some_block" as="someBlock">
              <action method="setBlockId"><block_id>some_block</block_id></action>
          </block>
      </reference>
      <reference name="left">
          <block type="cms/block" name="some_totally_different_block" as="someTotallyDifferentBlock">
              <action method="setBlockId"><block_id>some_totally_different_block</block_id></action>
          </block>
      </reference>
   </foo>
   <bar>
      <update handle="foo" /> 
      <reference name="header">
          <block type="cms/block" name="some_other_block" as="someOtherBlock">
              <action method="setBlockId"><block_id>some_other_block</block_id></action>
          </block>
      </reference>
   </bar>
</layout>

bar 的生成 XML 将是：

<layout>
   <bar>
      <reference name="header">
          <!-- Start of part pulled in from foo -->
          <block type="cms/block" name="some_block" as="someBlock">
              <action method="setBlockId"><block_id>some_block</block_id></action>
          </block>
          <!-- End of part pulled in from foo -->
          <block type="cms/block" name="some_other_block" as="someOtherBlock">
              <action method="setBlockId"><block_id>some_other_block</block_id></action>
          </block>
      </reference>
      <!-- Start of part pulled in from foo -->
      <reference name="left">
          <block type="cms/block" name="some_totally_different_block" as="someTotallyDifferentBlock">
              <action method="setBlockId"><block_id>some_totally_different_block</block_id></action>
          </block>
      </reference>
      <!-- End of part pulled in from foo -->
   </bar>
</layout>

tl;dr:update 句柄基本上是“将此布局与我当前的布局合并”。

Answer 2

此句柄用于将现有布局句柄合并到当前布局。 在您的示例中，<update handle="editor"/> 将添加到 <adminhtml_catalog_product_edit> 以下内容：

<editor>
    <reference name="head">
        <action method="setCanLoadExtJs"><flag>1</flag></action>
        <action method="addJs"><script>mage/adminhtml/variables.js</script></action>
        <action method="addJs"><script>mage/adminhtml/wysiwyg/widget.js</script></action>
        <action method="addJs"><script>lib/flex.js</script></action>
        <action method="addJs"><script>lib/FABridge.js</script></action>
        <action method="addJs"><script>mage/adminhtml/flexuploader.js</script></action>
        <action method="addJs"><script>mage/adminhtml/browser.js</script></action>
        <action method="addJs"><script>prototype/window.js</script></action>
        <action method="addItem"><type>js_css</type><name>prototype/windows/themes/default.css</name></action>
        <action method="addItem"><type>js_css</type><name>prototype/windows/themes/magento.css</name></action>
    </reference>
</editor>

(“编辑器”句柄定义在app/design/adminhtml/default/default/layout/main.xml)