In this blog, you will change the colours in this app from purple to blue as seen below. The colours are defined in the app/res/values/colors.xml file and how these colours are applied to the app are defined in the app/res/values/themes.xml file.

1. Open colors.xml and add the xml code for two colours blue and navy as follows.

2. Open themes.xml, change the purple colours in colorPrimary and colorPrimaryVariant to blue and navy, respectively.

3. Run the project and verify the colours on the main activity.