button01.setBackgroundColor(getResources().getColor(R.color.red));
color.xml
colors.xml <?xml version="1.0" encoding="UTF-8"?> <resources> <color name="red">#f00</color> <color name="green">#0f0</color> <color name="blue">#00f</color> <color name="black">#000</color> </resources>