How to properly remove padding (or margin?) around buttons in Android?

Question

Currently, I have the following bottom log in button.

When button is not being pressed

When button is being pressed

The XML loo

Answer 1

In styles.xml

In values/drawable:

my_drawable.xml

selector.xml

In values/drawable-v21:

my_drawable.xml

selector.xml

In layout:

Result on API 19:

Result on API 21:

Source code