out_activity.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:tools="http://schemas.android.com/tools"
    xmlns:android="http://schemas.android.com/apk/res/android"
    tools:ignore="ResourceName">
    <alpha
        android:duration="300"
        android:fromAlpha="1"
        android:toAlpha="0"
        />
</set>