Transition drawable - fade between two drawables, colors, whatevers!

activity.java

d = (TransitionDrawable) myLittleButton.getDrawable();
d.startTransition(DURATION);

qs_background_transition.xml

<?xml version="1.0" encoding="UTF-8"?>
<transition xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- The drawables used here can be solid colors, gradients, shapes, images, etc. -->
    <item android:drawable="@color/quicksettings_background" />
    <item android:drawable="@color/semitransparent_grey" />
</transition>