Telegram / TMessagesProj / src / main / res / anim / popup_out.xml

<?xml version="1.0" encoding="utf-8"?>

<set xmlns:android="http://schemas.android.com/apk/res/android">
    <alpha android:fromAlpha="1.0"
        android:toAlpha="0.0"
        android:duration="150"
        android:interpolator="@android:anim/accelerate_interpolator"/>
</set>