Answer
In order to define a colors that can be used in your app, define it an a resource file.

e.g. the resource file can be named as color.xml in the res/values directory of your project as:

res/values/color.xml

  1. <?xml version="1.0" encoding="utf-8"?>
  2. <resources>
  3.     <color name="White">#FFF</color>
  4.     <color name="Black">#000</color>
  5.     <color name="Grey">#7F7F7F</color>
  6. </resources>