Answer

Create an xml file in the res/values directory called as colors.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="White">#FFF</color>
    <color name="Black">#000</color>
    <color name="Grey">#7F7F7F</color>
    <color name="DarkGrey">#4F4F4F</color>
    <color name="Green">#0F0</color>
    <color name="TransparentGrey">#7F000000</color>
</resources>   

You can define what ever colors you want as resources as it is shown above. Once defined, the Android compiler will automatically create resources identifiers in the R file that you can refer in your code as show below:

  public static final class color {
        public static final int Black=0x7f060001;
        public static final int DarkGrey=0x7f060003;
        public static final int Green=0x7f060004;
        public static final int Grey=0x7f060002;
        public static final int TransparentGrey=0x7f060005;
        public static final int White=0x7f060000;
    }

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