solr LowerCaseFilterFactory not working

问题:

For case-insensitive sort in solr, I have added the following in the config:

<fieldType class="org.apache.solr.schema.TextField" name="TextField" sortMissingLast="true" omitNorms="true">
  <analyzer>
    <tokenizer class="solr.KeywordTokenizerFactory"/>
    <filter class="solr.LowerCaseFilterFactory"/>
  </analyzer>
</fieldType>

and the field as follows:

<field indexed="true" multiValued="false" name="nm" stored="true" type="TextField" docValues ="true"/>

I have tried: solr case insensitive sort not working, but it is still not working.

I am new to solr, can anyone please tell me whats going wrong here.