The gist demonstrates how to create a custom Tabris.js Android theme.

cordova_config.xml

<?xml version='1.0' encoding='utf-8'?>
<widget 
  xmlns="http://www.w3.org/ns/widgets"
  id="com.eclipsesource.sandbox.theme" 
  version="1.0.0">
  
  <name>Tabris.js Android Theming Sandbox</name>
    
  <hook type="after_platform_add" src="scripts/android/afterPlatformAdd.js" />
    
  <platform name="android">
    <preference name="Theme" value="com.eclipsesource.sandbox.theme.R.style.Theme_Sandbox" />
  </platform>

</widget>

cordova_resources_android_res_values_themes.xml

<?xml version="1.0" encoding="utf-8"?>
<resources xmlns:android="http://schemas.android.com/apk/res/android">

    <style name="Theme.Sandbox" parent="@style/Theme.Tabris.Light.DarkActionBar">
        <item name="colorPrimary">#3F51B5</item>
        <item name="colorPrimaryDark">#303F9F</item>
        <item name="colorAccent">#FF4081</item>
    </style>

</resources>

cordova_scripts_android_afterPlatformAdd.js

#!/usr/bin/env node

var fs = require('fs');
var path = require('path');

module.exports = function(context) {
  var androidPlatformDir = path.join(context.opts.projectRoot, "platforms/android");
  if (fs.existsSync(androidPlatformDir)) {
    var srcDir = path.join(context.opts.projectRoot, "resources/android/res");
    var targetDir = path.join(context.opts.projectRoot, "platforms/android/res");
    copyRecursiveSync(srcDir, targetDir);
  }
}

var copyRecursiveSync = function(src, dest) {
  var exists = fs.existsSync(src);
  var stats = exists && fs.statSync(src);
  var isDirectory = exists && stats.isDirectory();
  if (exists && isDirectory) {
    if (!fs.existsSync(dest)) {
      fs.mkdirSync(dest);
    }
    fs.readdirSync(src).forEach(function(childItemName) {
      copyRecursiveSync(path.join(src, childItemName), path.join(dest, childItemName));
    });
  } else {
    fs.linkSync(src, dest);
  }
};

package.json

{
  "title": "Tabris.js Android Theming Sandbox",
  "main": "src/app.js",
  "dependencies": {
    "tabris": "^1.0.0"
  }
}

src_app.js

var page = tabris.create("Page", {
  title: "Tabris.js Theming",
  topLevel: true
});

tabris.create("CheckBox", {
  text: "Custom Theme",
  layoutData: {left: 16, top: 16}
}).appendTo(page);

page.open();