Deactivate layout update with module deactivation in magento -

i'm programming magento module. i've been wondering, how deactivate layout updates of module, deactivating module. wan't deliver possibility recover changes done module if it's inactive.

here's config.xml:

<?xml version="1.0" encoding="utf-8"?> <config>      <modules>         <bss_tierpreis>             <version>0.0.5</version>         </bss_tierpreis>     </modules>      <global>          <models>             <tierpreis>                 <class>bss_tierpreis_model</class>             </tierpreis>         </models>          <blocks>             <tierpreis>                 <class>bss_tierpreis_block</class>             </tierpreis>         </blocks>      </global>      <frontend>         <layout>             <updates>                 <tierpreis>                     <file>tierpreis.xml</file>                 </tierpreis>             </updates>         </layout>     </frontend>  </config> 

tierpreis.xml:

<?xml version="1.0"?> <layout version="0.1.0">     <catalog_product_view>         <reference name="head">             <action method="addcss">                 <name>css/tierpreis.css</name>             </action>         </reference>         <reference name="content">              <reference name="alert.urls">                  <block type="tierpreis/getlist" name="tierpreis_getlist" template="tierpreis/list.phtml" />             </reference>         </reference>        </catalog_product_view> </layout> 

it's annoying css file loaded while module not active. there way avoid it?

you can use ifconfig parameter

<reference name="head">  <action method="settemplate" ifconfig="module/general/enabled">    <template>route/to/template</template>  </action> </reference> 

you need set 1 dropdown module enable/disable in yourmodule in admin panel , set value "0" => "no" save , add path in layout file ifconfig parameter.