naming_convention.xml

<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
    "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
    "https://checkstyle.org/dtds/configuration_1_3.dtd">

<module name = "Checker">
  <property name="charset" value="UTF-8"/>
  <property name="localeLanguage" value="en"/>

  <property name="severity" value="error"/>

  <property name="fileExtensions" value="java, xml, png, jpg, webp"/>

  <!-- Checks for file naming  -->
  <module name="RegexpOnFilename">
    <property name="folderPattern" value="[\\/]src[\\/]\w+[\\/]res[\\/]drawable"/>
    <property name="fileNamePattern" value="^((bg)|(ic)|(sel)|(img))_([a-z0-9]+[_\-]?)+(\.9)?\.((png)|(jpg)|(webp)|(xml))$"/>
    <property name="match" value="false"/>
    <message key="regexp.filename.mismatch" value="Drawables should begin with ''bg_''(background), ''ic_''(icon), ''sel_''(selector) or ''img_''."/>
  </module>

  <module name="RegexpOnFilename">
    <property name="folderPattern" value="[\\/]src[\\/]\w+[\\/]res[\\/]layout"/>
    <property name="fileNamePattern" value="^((activity)|(fragment)|(dialog)|(view)|(item)|(btn))_([a-z0-9]+[_\-]?)+\.xml$"/>
    <property name="match" value="false"/>
    <message key="regexp.filename.mismatch" value="Layouts should begin with ''activity_'', ''fragment_'', ''view_'', ''dialog_'', ''item_'' or ''btn_''."/>
  </module>

  <module name="RegexpOnFilename">
    <property name="folderPattern" value="[\\/]src[\\/]\w+[\\/]res[\\/]values"/>
    <property name="fileNamePattern" value="^((attr)|(color)|(dimen)|(string)|(style))[s]?(_[a-z0-9]+)*\.xml$"/>
    <property name="match" value="false"/>
    <message key="regexp.filename.mismatch" value="Values should begin with ''attrs_'', ''colors_'', ''dimens_'', ''strings_'' or ''styles_''."/>
  </module>

  <module name="RegexpOnFilename">
    <property name="folderPattern" value="[\\/]src[\\/]\w+[\\/]res[\\/]"/>
    <property name="fileNamePattern" value="^([a-z0-9]+[_]?)+(\.9)?$"/>
    <property name="match" value="false"/>
    <property name="ignoreFileNameExtensions" value="true"/>
    <message key="regexp.filename.mismatch" value="Resource files should use ''snake'' names (lower case, concatenated by underscore)."/>
  </module>

  <module name="RegexpOnFilename">
    <property name="folderPattern" value="[\\/]src[\\/]\w+[\\/]java[\\/]"/>
    <property name="fileNamePattern" value="^[I]?([A-Z][a-z0-9]+)+$"/>
    <property name="match" value="false"/>
    <property name="ignoreFileNameExtensions" value="true"/>
    <message key="regexp.filename.mismatch" value="Java files should use camel names."/>
  </module>

  <module name="RegexpOnFilename">
    <property name="folderPattern" value="[\\/]src[\\/]((androidTest)|(test))[\\/]java[\\/]"/>
    <property name="fileNamePattern" value="^((\w+Test)|(Base\w+))\.java$"/>
    <property name="match" value="false"/>
    <message key="regexp.filename.mismatch" value="All files in the ''src/androidTest/java'' or ''src/test/java'' folder should be named ''*Test.java'' or ''Base*.java''."/>
  </module>

</module>