In properly extending dimsuz's answer by providing a real code situation, see the following code snippet:
Drawable buttonDrawable = button.getBackground();
buttonDrawable = DrawableCompat.wrap(buttonDrawable);
//the color is a direct color int and not a color resource
DrawableCompat.setTint(buttonDrawable, Color.RED);
button.setBackground(buttonDrawable);
This solution is for the scenario where a drawable is used as the button's background. It works on pre-Lollipop devices as well.