<?xml version="1.0" encoding="utf-8"?>
<set 
	xmlns:android="http://schemas.android.com/apk/res/android"
	android:interpolator="@android:anim/accelerate_decelerate_interpolator">
	<!-- change opacity from 1 to 1/2 and back -->
	<alpha xmlns:android="http://schemas.android.com/apk/res/android"
		android:fromAlpha="1.0"
		android:toAlpha="0.5"
		android:startOffset="0"
		android:duration="400"
	 />
</set>