Update activity_main.xml

In the prior example, the custom KeyboardView style was not being used at all.

While you have added all the KeyboardView attributes properly (attrs.xml) allowing you to reference them in the xml as was shown, it's better to reference the style.

Doing so will allow you to change only those items that need to be changed for that instance, via xml. Without referencing the style, you have to manually specify everything (as you were doing).